Really good additional information:

Thanks to Paul Burns, another RVer in Great Britain, he has collected a lot of excellent information on the Magnetek Power Converters which includes much of the information we had placed on these web pages.    Paul has offered to share his information via these pages which should be a big help to anyone attempting to repair their unit.  Some of these items did not transfer to the webpages too well.   For instance, there is a nice flowchart to help you, step by step, to find a solution to your problem.  The complete file, in .pdf format, is available for download by clicking here.  Thanks Paul.


6300 Series Owner/Operator Manual


When 120 VAC is connected to Power Center via commercial power or AC generator, the 120 VAC circuits are protected by the breakers contained in the AC PANELBOARD.  120 VAC circuits may be turned off by flipping breaker to indicate “OFF.” The circuits may be turned on or reset by flipping breaker to indicate “ON.”  12 V DC FROM POWER CONVERTER SECTION When 120 VAC is connected to the Power Center via commercial power or AC generator, and the circuit breaker controlling the POWER CONVERTER Section is “ON”, the POWER CONVERTER Section will convert the 120 VAC to 12 VDC and is instantly switched—via the Automatic Relay—into the 12 VDC RV circuits to operate the 12 volt lights and motors. A cooling fan will come on when certain temperatures are reached in the lower section. Equipment limited to operation from 12 volt battery power only—including 12 volt TVs, radios, stereos, unfiltered fluorescent lights—must be connected to the fused battery circuits of DC DISTRIBUTION PANEL or RV battery line.

DO NOT connect equipment requiring more than 3 amps to terminal “B”. AUTOMATIC-RESET THERMAL BREAKER A protective Thermal Breaker will “break” the 120 VAC power to POWER CONVERTER Section of Power Center if POWER CONVERTER becomes overheated—by operation above its maximum limit for an extended period of time or obstruction of ventilation to unit.  POWER CONVERTER Section will instantly switch 12-volt light and motors to battery.  In either case, the Thermal Breaker will reset itself after a period of time, and the lights and motors will again resume operation from POWER CONVERTER Section—only to shortly again “break”. When this occurs, take immediate steps to correct cause of overheating. A portion of RV 12-volt load—lights or motors or both—should be turned off to reduce total load. Also, inspect POWER CONVERTER Section to make certain ventilation is not obstructed.


When 120 VAC is NOT connected to Power Center via commercial power or RV generator, the POWER CONVERTER section—via its Automatic Relay—will switch RV battery into the circuit for power to operate 12 volt lights and motors.  When 120 VAC is again available, connect it to Power Center. The POWER CONVERTER Section—through its Automatic Relay—will be brought back into circuit.   When operating RV 12-volt equipment from RV battery, it is recommended that the amount of equipment in use be reduced—to conserve battery.  Gradual dimming of lights and slowing of motors indicates low battery voltage. If 12 volt equipment will not operate from RV battery, check wiring between 12 volt DC DISTRIBUTION PANEL in Power Center and battery.

If this line is fused and fuse is “blown,” inspect for overload or “short”. DO NOT install oversize fuse. Make certain battery is fully charged—see No. 5 below. 


The DC DISTRIBUTION PANEL is located behind hinged door of Power Center. This panel contains circuits with replaceable fuses for protection of RV 12-volt light and motor lines. If any line is loaded beyond the capacity of its fuse, the fuse will “blow”. A portion of the 12-volt load on the line—lights and/or motors—must be turned off to reduce total load on the line below the capacity of the fuse.

Replace fuse with same size fuse. DO NOT install larger fuse than indicated.  If this reduction of load on the line does not stop the “blowing” of the replaceable fuses, there may be a “short” along the 12-volt line or at a nonfused 12-volt motor on the line. Check the RV 12-volt line and equipment on the line. Locate the “short” and take the necessary steps to repair it.


If 12 volt lights and motors will NOT operate as indicated above, check to make certain 120 VAC power is properly attached to RV. Also, make certain the AC breakers in the AC PANELBOARD indicate “ON”. 


Units with Option C contain an automatic, solid-state Battery Charging Section. When 120 VAC power is connected to Power Center, the Charging Section will automatically “sense” the condition of RV battery. If it is below “full charge,” the Charging Section will start charging the battery.

If RV battery has been drawn down quite low, it will be charged at a relatively high amperage rate. If battery has not been severely drained, it will be charged at lower amperage rate. The rate of charge will decline as the battery reaches “full charge”. After battery reaches “full charge”, the Charging Section will drop back to “maintenance” level. It will not resume active charging until battery again falls below “full charge”. If your storage battery cannot be charged as described above, it is possible the battery is defective—see “Battery Maintenance” below.


WARNING—Before inspecting or servicing storage battery, read and follow battery manufacturer’s cautions and directions.  Your RV storage battery must be properly maintained so it can perform its functions as described in 3 & 5. The following suggestions—plus those of battery manufacturer—will help your storage battery:

The battery must be in good condition with water at proper level when first installed in RV.

When 120 VAC is connected to Power Center, check battery once a week.   As battery ages, it will usually need water added more often.  If 120 VAC is not connected to Power Center, it should be reconnected to Power Center once a month for 8-12 hours to “recharge” battery.

If you store battery outside of RV, a battery charge should be connected to it a least once a month to recharge battery.

Do not allow battery to remain in discharge condition—it will become sulfated and not accept a proper “charge”.

Some situations which may indicate need for battery replacement are:

The loss of more water in one cell than others. Continuous loss of water in all cells—perhaps accompanied by overheating of battery, gassing and extreme bubbling.  A marked difference in the specific gravity reading between one cell and others.



Parallax Power Components L.L.C. warrants its products to be free from defects in material or workmanship under normal use and service and limits the remedies to repair or replacement.  This warranty extends for two years from the date of purchase and is valid only to the original owner and within the continental limits of the United States and Canada.

If a problem should occur with you Parallax Power Components L.L.C. converter within the first twenty-four months after purchase, please contact a dealer that handles warranty on your brand of RV. No user serviceable parts inside.

Parallax Power Components L.L.C.

112 E. Union St.

Goodland In 47948

Telephone: 1-800-443-4859

Parallax Power Components L.L.C.

Series 6300 A



MODELS 6325, 6332, 6336, 6345, and 6350 contains these standard features:

AC PANELBOARD—120 volts AC 30 amp—for AC branch circuit distribution and protection within the Recreational Vehicle (RV).

POWER CONVERTER—Provides 12 volt DC –up to load limit—to operate 12 volt lights and motors in RV when connected to 120 volt AC power source.

6325—designed for 25 amps maximum continuous load

6332—designed for 32 amps maximum continuous load

6336—designed for 36 amps maximum continuous load

6345—designed for 45 amps maximum continuous load

6350—designed for 50 amps maximum continuous load

Features Automatic Relay to switch between the converter and RV battery for 12 volt DC power for RV.

Battery Charging Section—Option C. Units with Option C contain an automatic, solid-state battery charging section.

DC DISTRIBUTION PANEL—Contains fused circuits for distributions of 12 volt DC within the RV.

The AC PANELBOARD and 12-volt DC DISTRIBUTION PANEL are found behind the hinged door of the Power Center.

Power Centers are suitable for vertical wall mounting and are to be wired per directions furnished with Power Center. For proper operation, owner must not obstruct ventilation openings in front panel of Power Center.

DO NOT DESTROY THIS GUIDE—For future reference, record

Date of RV Purchase_______________Series No.______________

Model No._______________________Option Code_____________

Disconnect shore power.

Battery must be connected.

Set volt meter to read 12 V DC.

Refer to the DC fuse block reference photo below for test points.

Apply meter probes to the test points indicated per steps 1 and 2 .

1. Measure battery voltage from terminals C. to terminal D.

2. Measure voltage from blue converter positive to terminal D.

3. Voltage measured at step 1 and at step 2 should be the same. If not, a problem with the

internal transfer relay(s) is indicated.

All information, drawings, flowcharts, and schematics are the property of Parallax Power Supply. All rights reserved. Refer installation and servicing to qualified

service personnel. Service information provided solely for use by Licensed Electricians and Certified RV Technicians. No endorsement of technical expertise, arising

from the use of the information supplied, is either expressed or implied.

6300/3200 Series Charging Circuit Service Information

1) DC circuit breaker and limit resistor should have continuity.

Limit resistor .3 ohm 50 watt Pt # 16506709

Limit resistor .3 ohm 30 watt Pt# 16506517

Limit resistor .15 ohm 50 watt Pt# 16506718

Circuit breaker Pt # 1-AB15Q

2) If above ok, proceed to next tests

3) Jumper yellow wire to aluminum heatsink.

4) If voltage at "C" rises charger PCB is defective.

Pt # 090-6300-001-44 (7 Wire Q Board)

Pt # 91500022 (5 Wire "CC" option Board)

Note** 91500022 5 wire "CC"" phase control board is obsolete.

May use 7 wire Q board, but do not use fan control wiring.

Pt # 090-3200-001-44 (4 Wire Board)

5) If voltage at "C" does not rise, SCR is defective.

Pt # 1-18526667

Pt # 1-18526725 (35 amp 220 volt SCR "CC" option)

Contact the following RV parts distributor concerning parts availability

or converter system replacement options.

Master-Techs Inc.


October 04, 2002

Application Notes: Proper identification of Parallax Power

Components PowerCenter system components.

Problem: Mismatching of DC Distribution Fuse Panels and lower section converter units due to improper servicing will lead to 12 volt system problems primarily indicated by:

1. Battery “overcharging” or “not charging at all”.

2. 15 - 20 VDC measured on the 12 VDC system. Lamp brightness may be high or lamps may fail prematurely.


1. Verify model number as listed on the model label. Location:

Inside upper door on left side of door panel.

2. Verify the number and color of the leads wired to the DC Distribution Fuse Panel. Location: Upper section right side.

3. If you have 3 leads, 1 ea. colored red, white, and blue, you have a 6300 Series linear lower section.

4. If you have only 2 leads, 1 ea. colored blue and white, you have a 7300 Series Electronic Switchmode lower section.

5. Verify that the model label, and the lower section are correct for the model series referenced on the model label.

6. Verify that the powercenter has the correct DC distribution fuse panel per service letter: AppNotes_DC FusePanels.pdf

If you have additional questions please call 1-800-443-4859 for RV Technical Service.

Marty Redd

Parallax Power Components L.L.C.

112 E. Union St. Goodland, In. 47948

Torque Spec 14-inch lbs. Maximum for all

DC branch load terminals.

Torque Spec 14-inch lbs. Maximum for all

DC branch load terminals.

Application Notes: DC Distribution Fuse Panels

Do not exceed torque specs on the DC Distribution Fuse Panel!

Damage to terminals or load wiring may be the result of improper torque.

This panel must only be used with 7300 Series Electronic Power Converters!

Note position of (2) 30-amp “reversed battery” protection fuses.

This panel must only be used with the 3200/6300 Series Linear Converters!

Note: No 30-amp “reversed battery” protection fuses on this panel.

Torque Spec

35 inch lbs.

30 amp “reversed

battery” protect fuses

DC load branch


DC load branch


Torque Spec

35 inch lbs.

Pt # 30091000000

Pt # 30506922

.3 OHM 50 WATT RESISTOR [BR-1-16506709] - $7.61 : MC Camping Supplies, Your Complete Camping Source

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Home :: Repair Parts :: Converter Parts :: Parallax :: .3 OHM 50



Product 2/30


Product Description

A resistor is an electrical component which provides some resistance to the flow of electricity. This resistance determines how much current will flow for a given voltage applied across the resistor. The result of resistance is the production of heat.  Incandescent light bulbs are specialized resistors, which gets so hot that they glow, produce light. Resistance is measured in ohms.

Used for 6300 CC option or Q series converters only.

This product was added to our catalog on Monday 02 February, 2009.

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.3 OHM 50 WATT RESISTOR [BR-1-16506709] - $7.61 : MC Camping Supplies, Your Complete Camping Source

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Parallax 110VDC DPDT Relay Parallax 6300 Series 140F Fan



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Copyright 2003-2006 MC Camping Supplies. Powered by Zen Cart

112 E. Union St., Goodland, IN 47948

Linear Series Troubleshooting Flowchart

Model Series 3200 and 6300

Converter DC Output Test

Shut off converter 120 VAC power at the breaker in the AC breaker panel.

Refer to the nameplate for circuit identification.

Disconnect battery (+) wire from the DC fuse block. USE



Remove all fuses from the DC fuse block.

Connect a DC voltmeter between the blue (+) wire from converter and the white (-) from the converter.

Turn 120 VAC power on at the AC breaker panel. Voltage should read 12.3 VDC – 13.3 VDC at 115 – 125 VAC input voltage.

Is the DC output voltage correct? No Yes

Converter is functioning properly.

Converter is defective.

Note: If using a digital voltmeter a small pre-load may be needed across the meter leads. Use a 1 K-ohm resistor or a small test light for this pre-load. If no pre-load is used with digital meters the output voltage may read 1-2 volts higher than normal.

Analog voltmeters will not require this pre-load.

Battery Charger Test

Shut off converter 120 VAC power at the breaker in the AC breaker panel.

Refer to the nameplate for circuit identification.

Verify that the battery is fully charged.

Reconnect the battery (+) wire to the battery input terminal on the DC fuse block. Refer to the wiring label for terminal identification.

Connect a DC voltmeter across battery (+) and (-) terminals at the DC fuse block. Note the battery voltage.

Turn the converter AC power back on and check for an increase in battery voltage, usually 0.5 volt or more.

Does the voltage increase when AC is applied to the converter?

No Yes

Charger is functional.

Charger is defective.

Note: If DC voltage increases when fuses are

reinstalled, refer to flowchart LinearSeriesBatOvrChg.


Linear Series Troubleshooting Flowchart

3200/6300 Battery Overcharging

Step 1.

Measure DC voltage across blue (positive) to white (negative) at DC fuse panel or DC output leads. Voltage should measure 12.0 - 14.1volts DC.

Step 2.

Note-This step requires a “true RMS” voltmeter.

Set meter to read AC Volts. Verify AC “ripple” voltage between 6 and 8 volts measured across “unfiltered” blue (positive) to white (negative) at DC fuse panel or DC output leads.

Is “ripple present?

No Yes

Step 4. ***See Note ***

Measure charger DC output voltage across “C” (positive) to “D” (negative) at internal DC fuse panel, or between red (positive) to white (negative) DC output leads.

Is DC voltage 13.5 – 14.1 volts?

No Yes

Charger is functioning correctly.

Step 5.

Remove all DC load fuses from DC distribution panel connected to “unfiltered” blue (positive) wire. Recheck for AC “ripple”. Is “ripple” present?

Yes No

Verify system components if troubleshooting a 6300 series linear converter per AppNotes_DCFusePanels.

Step 6.

Plug DC load fuses in one at a time. Check for “ripple” after each fuse is installed. If a circuit removes the “ripple” when its fuse is installed, move that load circuit to a load terminal connected to the charger output. “Ripple” should still be present after all “unfiltered” load circuits fuses are reinstalled.

Retest for charger output voltage of 13.5-14.1 volts

DC. Is voltage correct?

Yes No

Step 3.

Verify battery bank condition by load test or specific gravity check. Replace defective batteries.

Repair charger components or replace converter.

Return to Step 3.

112 E. Union St. Goodland, In. 47948

***Note: If using a digital voltmeter a small pre-load may be needed across the meter leads.

Use a 1 Kohm resistor or a small test light for this pre-load. If no pre-load is used with digital meters the output voltage may read 1-2 volts higher than normal.

Analog voltmeters will not require this preload.



Repairing Magnatek RV Power Converter

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Repairing the Magnatek Power Converter

Note: This unit was in my Sierra 30 foot trailer

When spring came and I prepared to get my RV all un-winterized and ready to take out, I discovered that my

trailer battery was nearly dead. Since it was new from just the year before, I thought I wasn’t getting very

good mileage on batteries but I thought I would do some other checking before indicting the battery as

defective. First, doing some various voltage checks, I found that I had good 12 volts DC to my interior lights

and to the voltage monitor on the control panel. Hmmmmm….. that’s odd. That voltage was coming from the

power converter 12 volt supply (although not from the converter's battery charging section).

Checking the cigarette lighter socket, it only showed 5 volts and I determined that this was coming directly

from the battery which was, by then, in a near discharged condition. Although the trailer had been plugged in

all winter, the battery had not received any charge since the battery charge feature in the power converter

had failed in my Magnatek Power Converter, and I didn’t know when that had happened. The battery was

OK, the Magnatek higher current 12 volt section was OK but the battery charger section of the converter was

not OK.

Checking at the Magnatek panel in the bathroom, I found no voltage between point C (which was the

positive side from the battery) and point D (which was the negative side from the battery). Now I knew where

I had to concentrate my attention. NOTE: Points C and D are actually labeled as such on the unit.

At this point I spent several hours combing the Internet in search of a schematic for the Magnatek

converter….. totally without success. I read jillions of messages from RVers, several asking for the same

thing I sought. I wanted any kind of information, particularly a schematic, for this unit. I even contacted some

of these people to ask if they had been successful in the search. Nope…..nada…..nothing....... no such luck.

I found a telephone number for the factory which built the unit and even tried to call for info. Human help

was available for warranty work but my unit was several years out of warranty. I was out of luck.

I needed that schematic and since it was unavailable, it looked like I would have to generate one myself. If

you’ve ever tried to do this it is akin to somewhere between trying to write down a cake recipe from only

having the completed cake in front of you and unscrambling an egg. Not much fun, especially if the parts

have non-standard markings or no markings at all........ like my converter.

I was ultimately successful and the schematic I have included is close enough, if not an exact rendering, of

what is found in the Magnatek power converter. I hope it helps others as it helped me. Now, with schematic

in hand, I returned to the project of repairing my converter.

PIC #1: The circuit schematic is actually in two parts. The first part, shown above, is the main power supply

part of the converter. Thanks to a reader named Baldy in California, you'll be able to see the pictures better

than they originally were displayed. Baldy took my original pictures, which were upside down and sideways,

and corrected them for me. Thanks Baldy..

Repairing Magnatek RV Power Converter

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PIC #2: The schematic above is the battery charger part of the power converter. It will charge the RV

battery but then automatically taper down to a trickle charge so as not to destroy your expensive battery.

PIC #3: I included this picture but I'm not absolutely sure of its total accuracy. I drew this out several times

and I think this was the final version. Don't hold me to it, however, and if there is a discrepancy between the

schematic and the underside of the PC board, you should believe the schematic first.

UPDATE NOTE: Since publishing this original article someone sent me the actual schematics on a Magnatek RV power supply. Click here to go to copies of those two new pages.

CAUTION: When you decide to work on your power converter, be sure you unplug your trailer’s

power cable from the 117 volt AC mains. Once that is done you can remove the screws holding the

panel/cover onto the converter. This will expose the transformer, diodes, solenoid, fan and battery charge

board. This solenoid is energized whenever the trailer is plugged into external AC power and it allows the

converter to send charging voltage to the trailer battery. Magnatek chose to use a solenoid to activate a

switch to perform this function rather than use a relay. Why? I don’t know.

The following are steps required to remove all connections so you can pull the whole power converter out to

work on it:

1. Remove the 4 hex-head screws which hold the front board.

2. Remove the 2 hex-head screws holding the other board.

3. Remove the 12 volt wiring to the 12 v. distribution board – the white and red wires have screws, the blue

(12v) wire is attached with a screw and nut.

4. Open the cover to the 117v AC circuit breakers.

(You did disconnect the 117v AC didn't you?)

5. Remove the white wire which goes to the left side vertical screw strip.

6. Remove the black wire coming from the far right-hand circuit breaker.

7. Carefully feed the 2 AC and 3 DC wires from the top box so they are inside the bottom power supply box.

Now you can remove the power converter pieces.

8. With the power converter box on the workbench, remove 2 hex-head screws holding the nylon posts

Repairing Magnatek RV Power Converter

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which are holding the battery charger circuit board.

9. NOTE: With the power converter box on the workbench, the top cover can be removed with 4 hex-head

screws. This allows full access to the inside components.

The next step is to remove the board containing several electronic parts including resistors, silicon controlled

rectifier, zener diode and a capacitor. This board, on my unit, stood vertically and was attached to the righthand

wall of the supply. NOTE: Do NOT attempt to pop the board off the nylon posts where it is mounted. It

will not come off and attempting to pop it loose will result in a cracked board, which is made of rather fragile

phenolic material. Breaking that board can separate traces on the printed circuit board and you will have

additional problems. The board can be removed but only after the whole box, holding the supply, is

removed. (A word to the wise….. I hope.............. ask me how I know this...... No......... never mind.)

It is now that you must use your electronic trouble-shooting skills to determine which component or

components might be causing your problems. That is rather difficult for me to tell you what might be causing

your converter to fail but, hopefully, this information and the schematic provided will allow you to find it.

My problem turned out to be the large rectangular resistor mounted with a pop rivet to the back panel of the

box. The value was obscured on mine but an ohmmeter check showed the value to be more than a megohm

which was much, much too high. I would guess that its true value should have been less than an ohm but at

a high power rating, perhaps 50 – 100 watts. It was here that I had to do some guessing. Since this resistor

is located in the line providing charging current to the trailer battery, my guess is that its function is to drop

the load a bit when first connected to a battery which is totally discharged. A fully discharged battery would

place a tremendous temporary current load on the power supply components and this resistor helps to

protect things during that initial surge.

After the repair was complete, I did some checking on the converter to see just how much current was

provided to a battery for charging and to see whether the higher current stayed up at the high level or if it

tapered off to a trickle charge as this type of circuit should do. With a 0-3 amp meter in series with the

battery charging line, and using no extra resistance in the line (the big white rectangular resistor was shorted

to make zero ohms or there-abouts), I placed the charging circuit across a pair of 6 volt/7.7 AHr lead-acid

batteries which I had on hand. The ammeter started at just above 2 amps charging, then tapered down to

around 1.25 amps.

Then I tried it across a 12v/7 AHr lead-acid battery with was already charged. The current started a just

below an amp and within a minute, dropped to about 200 milliampres or .2 amps. I say "about" because the

ammeter constantly wiggled the equivalence of .1 amp. I suspected that this might be caused by the

noticeable AC ripple in the DC line. After all, there is no filtering on the rectified DC coming off the full-wave


I located a 2 ohm, 50 watt resistor in my junk-box to replace the defective one which had originally caused

my problem. Placing the charger wires across another charged 12v/7 AHr battery it started the charge

current at less than an amp. It also tapered down, within a couple of minutes, to about .2.amps…… a shaky

.2 amps. The resistor did not even run warm but it had very little current through it.

I finally found a .25 ohm/5 watt resistor and placed it in the place of the original defective white rectangular

unit pop riveted to the back wall of the converter. I feared that the power rating on this resistor might be too

low but I have used this one for several months and it is holding up well.

I reassembled my converter by going in reverse with the steps taken earlier to disassemble the unit.

Everything went back together as easily as it had come apart and I was a happy camper (so to speak). I

hope, if you are having problems as I was, that you can use some of this information and have as much

Repairing Magnatek RV Power Converter

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success as I did.

One additional piece of information – the fan which you hear while the trailer is plugged into an external 117

v AC source, is actually running on 117 v AC rather than 12v DC and is thermostatically controlled. A

temperature sensor is attached to the aluminum heat sink which holds the power diodes. When they are

doing their job and supplying 12 volt power to your trailer (not particularly to the battery) those diodes will run

hot and make the heat sink also quite hot. The sensor turns on the fan which blows across the heat sink as

well as our now familiar power resistor. If you don’t hear the fan then the power converter is not having to do

much work and the fan gets to rest.

One other benefit on my converter is, I was able to clean up all the dust and "grunge" around the fan and it

has become much quieter. I still hear it but nothing like it was previously.

Just as a final encouragement for you to try to repair your own converter, when I looked up the replacement

converter in a trailer accessories catalog, the replacement unit was between $200 and $300. That was

enough inducement for me to attempt my own repairs.

Jim Pickett – K5LAD

Written June 29, 2002 ---- Updated 07/23/09

Updated Additional Information

I received an email from Pete Sweeny with the following information and I thought it was very worthwhile to

add here:

Good evening,

I found your article most helpful. I recognized the resistor as what is commonly called an

ignition resistor or ballast resistor. They were used in many Chrysler products before electronic

ignition systems came into use. I found that a Sorenson brand part number GCR7 will work, it

is available at Advanced Auto parts for $3.88. It has no potting material around the resistance

wire thus it will run cooler as well as a raised place where the unit fastens to the cabinet, this

will also allow for better air flow.

Thanks Pete

I received another email from Tom Holley in Canada. He writes:

After learning it was the same resistor as in the old Dodges, the same ones that we ALWAYS

had a spare of in the glove compartment, I checked that first. I jumpered it with my ammeter

when I had the battery out and all the lights in my camper would work. They have not done

that since I bought it used! No wonder my battery would not charge while plugged in! I then

removed it and ohmed it... open circuit. The new one cost me $8.99 at the Canadian Tire

store part # 18-4506 ( for us Canadians )

I just wanted to thank you for saving me the cost of a converter!

Repairing Magnatek RV Power Converter

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Thanks Tom

Also I had found some other information which I've shared with several others who have have

written me. I've copied this same part of a message to their answers several times, so it might

be best just to reproduce it here for anyone else. The person had asked me about replacing

the fan and I sent him back the following information:

Hi Dennis --

I replaced my fan with a 117v AC muffin fan which was about 4" square, as I recall. These fans

should be available in electronics supply stores, hamfests, or even computer stores. The one I

used was from the surplus market somewhere and was one I had kicking around. If you go

this route, be sure you get a 117v AC unit as a lot of the fans you'll find surplus are 12 volt

DC. The Magnatek fan only runs when you're plugged into city electrical mains.

As far as other parts for the unit --- "official Magnatek parts" I once had a catalog I got from an

RV store. I tried to find it today but, alas, no luck. I dug back through some older messages

and will copy what I sent to another RVer about this book:

Sounds like you found a pretty good deal and I think that might be wise. I might recommend

that you find a book (actually a catalog) called "2004 RV Parts & Accessories." It's an 8 1/2 x

11 inch book that's just over 3/4" thick. I got mine from one of the RV dealers in Tulsa and it

was a freebie. I don't know if you've got some of those around you but it might be worth a call

to a dealer or two. It's one of those books which is published for "the world" but has this

dealer's name, logo, address, and phone numbers on the cover. They say that many of the

items in the catalog are stocked but if you find something which they don't have, they can order

it for you......... kinda like the old Sears and Roebuck catalogs. In this catalog I found, not only

brand new items (including power converters) but also some (note SOME) parts to repair

existing equipment. For instance, on page 116 I'm seeing replacement parts for Magnetek

Converters like: door latches, limit resistors, the PC board, fan motor, and relay. The prices

are surprisingly economical.

Perhaps if you can locate a store with one of these books you could find a direct replacement

for your fan. The truth is, the muffin fan I put into my unit is a LOT quieter than the old original


69272 hits since October 12, 2002

I received another email from Mark Tabbert who wrote:

I have a friend who needs help with his converter and I think I found the right place. He insists

that it is the fan or lack there of that is causing his converter to overheat. It does not trip the

thermal breaker but the fan never comes on either he says. I was wondering if you could me

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with the testing required to check the fan and the switch or heat sensor that controls when it is

on and off?

Thank you in advance,


My answer to him might be helpful to others who have had the same problems and question:

Hi Mark --

I'm certainly no expert on Magnatek converters........ I'm just someone who was desperate

because mine was broken and I couldn't find any information on the Internet about it.

Necessity is the mother of invention, at least it was for me..

.......If I were testing my converter to see if the temperature switch was working, I'd set it up on

the bench and blow a heat gun (or my wife's hair dryer) on it. If the converter was plugged in

to 110 volts AC and the fan didn't come on (with that heat on it), I'd know that either the fan

was defective or the temperature sensor was bad. Actually when I store my trailer at home, I

keep it hooked to the AC mains all the time. When I go inside on these really hot days, my fan

is usually running. Not because the converter is generating lots of 12 volt DC power, but

because the excessive temperature closes the temperature sensor switch in my trailer. If the

fan doesn't come on when you blow hot air on it, disconnect it from the AC mains and

try the heat source again. Once it has been heated up, measure across the temp sensor switch

with a continuity meter - or a VOM (Volt Ohm meter) set to low ohms. You should see either a

short across the switch meaning that it has closed or at least a low resistance (only a few

ohms at most). If that test fails, the sensor is bad and must be replaced (try an automotive

supply store). If the switch closes with heat, then it's good and the problem is probably a fan

which needs to be replaced.

The fan is a 110v AC fan and not a 12v DC fan like they sell at computer stores. Don't put a

12v DC fan in there --- it would run REALLY FAST but not for very long before you would let all

the smoke out of it. Be sure any testing you do with that meter and any

replacement of any of the parts is done AFTER TURNING OFF THE POWER -

the 110 v AC!!!!!!!

BTW - If you must replace the temperature sensor, they'll want to know what temperature it

should close (be sure you get NO or normally open). You might look on the switch itself and

see if you can find a stamped number for the temperature for it. If not, like I said, my switch is

closing in a closed trailer on a hot day which is probably around 110-120 degrees so I'd start

somewhere around there.

I hope this has been some help for you and your friend. Good luck and 73, Jim - K5LAD

BTW - Yes, he needs that fan or it WILL overheat...... badly overheat. He will need to get this

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Then I quickly added another message:

BTW Mark --

I saw something just as I sent you the previous answer. If you must replace the thermal

sensor switch, don't use the term you used in your message here. The switch in the converter

is NOT a "thermal breaker" but is a thermal sensor switch. The difference is, a thermal breaker

is NC or normally closed and when it reaches a defined temperature, it OPENS and breaks the

circuit. The switch in the Magnetek converter is a NO or normally open switch and it closes

when the designed temperature is reached -- when the converter is running and gets plenty hot

and the fan is to start up to cool things back down.

Again, I hope this helps.

Jim - K5LAD

I received, yet another email from a reader who was having a problem with his Magnetek

converter. It didn't seem to be providing the 12 volt DC power to the inside lights, motors, etc.

when the battery was removed. This is the answer I sent him and, perhaps it might help

someone else with the same or a similar problem. (Sept. 20, 2007)

Hi Rodney --

It's no bother and I'm glad to help you if I can but I'm no rocket scientist on these units. I just

happened to have a need to fix my own unit and couldn't find any info on the Internet so I had

to do what I did.

If you're not real accustomed to looking at schematics, you might sit down with a friend who is

more up on that, but study the ones showing the power supply parts and don't worry too much

about the charging section. Maybe I should say study the bigger parts and don't worry about

the smaller pieces in the unit.

When the converter is plugged into the AC from your home (or wherever) there's a relay which

picks (pulls in) and supplies the 12 volts to rest of the trailer. If the battery is installed, that

battery will be across that 12 volt line in parallel. If it's not there, the power goes from power

components (transformer, diodes, etc.) THROUGH the relay marked RY1 in the better

schematic prints, and on to the area with the battery, then on to the rest of the trailer. It will

get to those connections up somewhere near where your big battery is stored. Again, even if

the battery's not there, the voltage still goes on to the remainder of the trailer.

If I understand your problem correctly, you're not seeing 12 volts DC to the internal things in

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the trailer which run on 12 volts (lights, heater motor, etc.) I'd check the relay first to make

sure it's pulling in. You can do that without opening anything up just by standing by the

converter inside the trailer and having someone plug your trailer into the AC. As soon as it

sees the AC (there are no switches you need to throw) you should hear the relay snap in. It's

not small and should be pretty noticeable. As I recall, it sounds like it could crack pecan shells.

If you're not hearing the relay, that's going to be your problem.

If you're hearing the relay, there are several places to look but it requires you to disconnect the

converter from all the wiring and place it on the workbench for further checking.

CAUTION: Be very sure you have unplugged your trailer from the AC mains before you ever

try to disconnect anything and remove the converter.

You'll need to see if the power supply is actually generating 12 volts. There a circuit breaker

on the input (primary) side of the transformer but if your fan is running, that's not the problem.

If you cannot measure 12 to 14 volts at the input connection to the relay then the problem is

either the transformer, a loose or broken wire, or one of the four diodes (marked D1-D4 in the

schematic). An AC voltmeter can verify that you are seeing 12-15 volts AC out of the

transformer secondary.

If all that checks out: relay pulling in, 12 volts DC to the input to the relay contact but no 12

volts DC out of the relay, the contacts are probably bad (dirty or burned up). Cleaning dirty

contacts may get you back in business but burned contacts will general require replacement of

the relay.

If you're getting 12 volts DC OUT of the relay side but nothing to the trailer, measure the

voltage with a DC voltmeter at the battery terminals with the battery removed or disconnected.

If you're getting 12 volts DC there but no lights, etc., your problem is in the wiring from that

point on to wherever they are connected and that may be anywhere, depending on your

trailer's construction.

If, however, you got 12 volts DC out of the relay but nothing at the battery terminals, your

problem is the wiring from the converter up to the battery. That's usually an easier one to locate

since it will be a fairly large piece of cable.

I'm afraid that's about the best help I can give you in troubleshooting your problem, assuming

that I've understood it correctly. If I misunderstood your problem, shoot it to me again and I'll

try again.

Good luck on your "project." It's not much fun but it should give you a real feeling of

satisfaction, once you've located and fixed the problem.

73, Jim - K5LAD

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Here is yet another email from someone who ran across my web page and used the

information available to repair his Magnetek converter. He went one step further and is sharing

the additional information he found which should help others.

On 23 May 2008 at 18:34, Ken Avery wrote:

Hi Jim;

I recently had an issue with my Magnetek and found your article on the web. First, Thank you,

article was very helpful. I also had a problem with charging and you article cut me to the

chase right away. My resistor, however, still had numbers, after a couple web searches and emails,

I arrived at the answer, numbers were, HEI PC50-.15 P10. Translation is as follows,

Huntington Electronic Inc., 50 watt, .15 ohms, +/- 10%. From manufacture, $10.00 each,

minimum 5 piece order, plus shipping.

Resolution; Newark Electronics, SKU: 28K6344, 50 watt, .15 ohm, +/-1%. $4.83+shipping.

Charging the battery like a charm.

Unit is on a Layton 24 foot fifth wheel, 35 amp Power Converter, Series 6300A, Model 6332

option QB.

Thanks once again Jim for posting you article on the web, hope this info can help someone

else as well. Cheers and happy camping.

Ken Avery

Thanks Ken - Jim

I received this note today with some helpful information attached:

Thank you for info and for circuit diagram even more. My resistor R1 had value on it. It is 0.3

Ohm 50 Watt. CB1 was my problem (Circuit breaker) and value is 12 Volt 10 Amps.

Bought in Napa Autoparts store. My unit was in Okanagan Camper and now is working

okay. Original problem was battery not being charged. Everything else worked just fine.


OK Al, Good to hear another success story. - Jim

Here's another from Chuck from February, 2009. He was able to find some additional

part numbers and repair his converter:

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Hi Jim,

Thought I'd send you an update and let you know how my repair went. I did basis

troubleshooting with the unit still in the 5th wheel. As suspected, I had the ~12-13 volts on

one side of the power resistor and nothing on the other side. Suspected it open. Jumpered it

briefly with a wire and confirmed that everything not working was now working. At my age,

LOL, laying on the floor too long hurts.

I removed the bottom unit per your instructions. A piece of cake, thank you. I removed the top

metal plate and unsoldered one end of the resistor. Confirmed--open resistor. I couldn't find the

part you recommended, but searched the auto part stores for a comparable ignition resistor

that was readily available. I found a 1.6 ohm 10 watt ignition resistor made by NIEHOFF part #

FF109. Used commonly in many Chrysler cars. Concerned about the ohmage, I found a .3

ohm 10 watt power resistor at a local electrnonics distributer. I soldered the 2 together in

parallel and with my poor meter read about .4-.5 ohms. I figured the combined wattage to be

about 20 watts. Installed them in the unit and all looked good. Checked the fan circuit and the

thermister and all looked good. Re-installed in the 5th wheel and has been running for 3 days

now with no problems. Current seems right and the resistors are barely warm and the batteries

are now charged fully.

Once again, Thank you so much for your and everyones help. Saved me about $250 . My cost

for both resistors was about $8. Thank you again.


That's super, Chuck. Magnetek loses another handful of money due to users doing their own repairs.

Thanks for writing. -- Jim

This is from John from January, 2009 on the same topic as above. He was able to find

some additional part numbers and repair his converter:


Your article was very helpful. I was working on the Magnetek series 6300A m/n 6345 which is

in my 95 Four Winds 5000 rv and found the same problem you described. Your directions sent

me to the same resistor that failed on your unit. After a little research I found a direct

replacement resistor from Master Techs, Inc. Their part number is 16506718 @ a cost of 10.00.

The phone number is 800-848-0558. Thanks very much for taking the time to post your



Hi John --

Thanks for writing and I'm glad the article helped you. I get messages weekly from folks who try to find

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repair info for these converters (on the 'net) and there just doesn't seem to be much out there.

I prepared the original article several years ago when I couldn't find anything. I figured if I had the

problem then others might also. I makes me happy that it's been useful for others. Hope you and yours

have a very Happy New Year and get to spend many happy hours in your RV.

73, Jim - K5LAD

Wonderful news update: (June 5, 2009)

Thanks to a reader named Chad Helmer, he's informed me that the

manufacturer now provides the information on the Magnetek converters

which we've long needed. Perhaps they realized, from all the hits on this

website, that there was a major need to help and serve their customers.

For whatever reason, we're all the beneficiaries. The manufacturer,

Parallax, has provided this information at:

In addition, Chad discovered a website which advertises the actual resistor

which is often the problem and needs replacement when the converter

refuses to charge the battery. It's at:


The price, at this time, is $7.61.

Thanks a MILLION, Chad. You've helped a lot of


Just a note: If you have been working on your Magnetek power converter, hopefully after

finding something helpful on these pages, and you discover some additional information which

might help other readers and converter owners, please drop me a note with the information. If

you don't mind, I'd like to add your info to this page to help others who come by later. It's like

the old story about the note found beside a lonely water pump. It offered a bottle full of water

for the passerby. It cautioned them not to drink that water but to prime the pump and wet the

leather piston seal in the pump with the water in the bottle. It then cautioned the user to be

sure to leave a bottle full of water for the next soul who came by with a thirst.

What Magnetek information I found seems to have helped numerous folks and what you've

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found could help even more. Let's share. Thanks! - Jim - K5LAD

More good information (July 23, 2009)

Good information arrived from reader Garret Hansen in Canada. He found his resistor was

also defective and his Magnetek power converter was not working. He wrote:

Thanks for the writeup. That was some very helpful information. I live in Canada and

searched the part number on the Canadian Tire site left in the one post on your site but

was unable to find it. I will let you know if I am able to source a replacement part locally in

Alberta and you can post it to help others from Alberta find the part.

Thanks, Garret

Then he sent a follow-up message:


I actually was able to find a supplier in Red Deer. Gord at that ordered a

50 watt 0.15 Ohm resistor today for me and should be in in two


The link to Parallax was good in that it has some good pictures in it but when I emailed them

about purchasing just the resistor it sounded like they wanted to sell me a replacement

upgrade kit as you can see from the response I received below.

MagneTek that will likely not be available from anyone locally. You can try J & J Sales in

Langly, B.C. at (604) 534-6336. If unavailable from J&J, I think your best option would be to

install a 7345RU upgrade kit. Information is attached. J&J would also carry the upgrade kit.

Marty Redd

RV Technical Support and Training

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Parallax Power Supply - A Division of Connecticut-Electric, Inc.

It looks like the company is willing to sell a parts kit which includes several items. If that would

fill the need for readers on this webpage, the order number is listed above and the

ParallaxPower link is listed above. Garret only needed and wanted the resistor to complete his

repair so he continued to search available sources.

......the part number is MC14730 made by Multicomp.


dp/28K6344 cost me $5.66 CDN.

Thanks Garret

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