Troubleshooting homebrew 4-1000A  Amplifier K5LAD
Created 2/09/2004:2 Version 8/15/2008:2
1. The blower does not come on when the   A. Improperly connected AC line A.  Reconnect AC line properly
    BLOWER switch is turned on.  (Neon   B. The amplifier circuit breaker is B. Re-engage the circuit breaker
    light indicates power through switch)       tripped  
    C. The blower is not plugged in C. Plug in the blower plug
    D. Power switch is not closing   D. Check it with an ohmmeter
2.  The filament does not light when the   A. Circuit breaker blown   A. Re-engage circuit breaker
     FIL. switch is engaged (Neon light   B. Varistor is defective B. Check varistor - Cold resistance is
     indicates power through the switch         about 300 ohms - Replace if bad
    C. Filament transformer is bad C. Cuss
    D. 4-1000A tube is bad   D. Cry
3.  No high voltage indication on voltmeter   A. Relay voltage from amplifier to   A. Plug it in
     when H.V. switch is thrown. (Neon light       power supply not plugged in  
     on full bright indicates 117v. AC to   B. One or both AC interlocks not B. Place top panel firmly on the
     socket on back panel)       closed (Neon light will not light if     amplifier and secure the screws
        an interlock is open)  
    C. Power supply switch in off position C. Place power supply switch in
       (Neon light is H.V. switch will light     REMOTE position
       dimly with switch in off position  
       indicating no load on relay line)  
       (Neon light dim - see #3-A above)  
    D. No voltage from power supply D. See if the bleeder resistor is
          dissipating any heat.  Make sure
         power supply is getting 234v. AC
           as indicated on PS voltmeter.
4. No voltage indication on AC voltmeter   A. Internal PS relay not thrown   A. Place toggle switch in LOCAL
    on the power supply         position to turn the power supply on
    B. Fuses blown B. Replace inside fuses with 15 amp
         cartridge fuses
      NOTE:  Cartridge fuses have been
          replaced with a front panel dual 15
          amp circuit breaker.  Breaker is
          wired to both cartridge fuses, now
          blown open.  They are still mounted
          in the original ceramic fuse holder.
    C. Relays will not throw and no C. One of the cartridge fuses has
        voltage is indicated on the meter.     fallen out of the fuse holder.  Since
          the circuit breaker is wired across
          the fuses, one or both sides of the
          circuit breaker is removed from the
Operational Notes:
While tuning up on 10 Meters, sparks and smoke was evident.  The plate parasitic choke, made of 3 - 150 ohm, 2 watt resistors
inside the coil was burned up --- the resistors.  The 3 resistors were replaced with 3 - 390 ohm 2 watt resistors (because I had
3 of that same value)  As of 2008, I haven't had any additional problems.
The amplifier stopped transmitting output, although it seemed to be tuning up.  (Actually I was loading up the tube plate)
Removing the left side panel I found the heavy wire (#12) from the tank coil to the antenna loading variable cap had unsoldered
itself.  It was attached mechanically and then resoldered.
Also, one of the thin wires to the antenna relay coil was dropping down between the armature and the relay coil.  This prevented
the armature from moving all the way closed and possibly preventing the contacts from closing.  I taped both coil lead so they
could not get in the way.