| Troubleshooting homebrew 4-1000A� Amplifier | K5LAD | |||||
| Created 2/09/2004:2 | Version 8/15/2008:2 | |||||
| PROBLEM | CAUSE | CURE | ||||
| 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 | ||||||
| ��� circuit. | ||||||
| � | ||||||
| Operational Notes: | ||||||
| 9/19/1994 | ||||||
| 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. | ||||||
| Sep-94 | ||||||
| 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. | ||||||