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Troubleshooting
homebrew 4-1000A Amplifier |
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K5LAD |
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Created 2/09/2004:2 |
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Version 8/15/2008:2 |
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PROBLEM |
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CAUSE |
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CURE |
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1. The blower does not come on when the |
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A. Improperly connected AC line |
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A. Reconnect AC line
properly |
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BLOWER switch is
turned on. (Neon |
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B. The amplifier circuit breaker is |
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B. Re-engage the circuit breaker |
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light indicates
power through switch) |
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tripped |
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C. The blower is not plugged in |
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C. Plug in the blower plug |
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D. Power switch is not closing |
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D. Check it with an ohmmeter |
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2. The filament does not light when the |
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A. Circuit breaker blown |
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A. Re-engage circuit breaker |
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FIL. switch is engaged (Neon light |
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B. Varistor is defective |
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B. Check varistor - Cold resistance is |
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indicates power
through the switch |
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about 300 ohms -
Replace if bad |
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C. Filament transformer is bad |
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C. Cuss |
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D. 4-1000A tube is bad |
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D. Cry |
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3. No high voltage indication on voltmeter |
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A. Relay voltage from amplifier to |
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A. Plug it in |
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when H.V. switch
is thrown. (Neon light |
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power supply not
plugged in |
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on full bright
indicates 117v. AC to |
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B. One or both AC interlocks not |
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B. Place top panel firmly on the |
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socket on back
panel) |
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closed (Neon light
will not light if |
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amplifier and
secure the screws |
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an interlock is
open) |
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C. Power supply switch in off position |
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C. Place power supply switch in |
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(Neon light is H.V.
switch will light |
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REMOTE position |
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dimly with switch in
off position |
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indicating no load
on relay line) |
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(Neon light dim -
see #3-A above) |
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D. No voltage from power supply |
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D. See if the bleeder resistor is |
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dissipating any
heat. Make sure |
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power supply is
getting 234v. AC |
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as indicated on PS
voltmeter. |
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4. No voltage
indication on AC voltmeter |
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A. Internal PS relay not thrown |
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A. Place toggle switch in LOCAL |
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on the power supply |
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position to turn
the power supply on |
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B. Fuses blown |
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B. Replace inside fuses with 15 amp |
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cartridge fuses |
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NOTE: Cartridge fuses
have been |
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replaced with a front panel dual 15 |
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amp circuit
breaker. Breaker is |
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wired to both
cartridge fuses, now |
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blown open. They are still mounted |
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in the original
ceramic fuse holder. |
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C. Relays will not throw and no |
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C. One of the cartridge fuses has |
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voltage is
indicated on the meter. |
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fallen out of the
fuse holder. Since |
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the circuit breaker
is wired across |
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the fuses, one or
both sides of the |
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circuit breaker is
removed from the |
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circuit. |
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Operational Notes: |
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9/19/1994 |
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While tuning up on 10 Meters, sparks
and smoke was evident. The plate
parasitic choke, made of 3 - 150 ohm, 2 watt resistors |
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inside the coil was burned up ---
the resistors. The 3 resistors were
replaced with 3 - 390 ohm 2 watt resistors (because I had |
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3 of that same value) As of 2008, I haven't had any additional
problems. |
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Sep-94 |
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The
amplifier stopped transmitting output, although it seemed to be tuning
up. (Actually I was loading up the
tube plate) |
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Removing the left side panel I found
the heavy wire (#12) from the tank coil to the antenna loading variable cap
had unsoldered |
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itself. It was attached mechanically and then resoldered. |
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Also, one of the thin wires to the
antenna relay coil was dropping down between the armature and the relay
coil. This prevented |
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the armature from moving all the way
closed and possibly preventing the contacts from closing. I taped both coil lead so they |
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could not get in the way. |
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