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Post by wolfie on Nov 9, 2015 19:59:58 GMT -7
My Ghia head has never given me any trouble until tonight. Last time I used it everything was fine. Turned it on tonight there was no sound at all. So after checking it out it looks like the rectifier tube is not lighting up. Power tubes seem to be working or at least they are glowing. Any help would be appreciated.
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Post by Paul (TRANE) on Nov 9, 2015 20:06:28 GMT -7
TROUBLESHOOTING
WARNING: Make sure you unplug the amp when changing fuses, and do not touch the metal pins of the tube sockets with your fingers.
NOTE: Do not assume that new tubes are good tubes. Many new production tubes are bad out of the box. Try to have tubes you know to be good for these troubleshooting procedures.
Part 1:
Remove ALL tubes from the amp.
Install new fuses.
Turn amp power on, and standby on.
Turn off and check fuses.
If the fuses are ok, your power transformer is OK.
Move on to part 2.
Part 2:
Install rectifier tube.
Turn amp power on, and standby on.
Observe rectifier for signs of arcing.
Turn off and check fuses.
If the fuses are OK, and the tube does not arc/spark your rectifier is OK.
Move on to part 3.
If a fuse is blown or your rectifier is arcing replace the rectifier and fuse with equivalent replacements and repeat part 2 of troubleshooting procedure.
Part 3:
Install power tubes.
Turn amp power on, and standby on.
Observe rectifier and power tubes for arcing or red plating for about 30 to 45s.
Arcing will most likely occur immediately, but red plating may take a few seconds.
Turn off and check fuses.
If the fuses are ok, and none of the tubes are arcing or red plating the output tubes are OK.
Move on to part 4.
If a fuse is blown or your output tubes are arcing or red plating or your rectifier is arcing, replace output tubes, rectifier, and fuse with equivalent replacements and repeat part 3 of troubleshooting procedure.
Part 4:
Install preamp tubes.
Turn amp power on, and standby on.
Test amp for sound or noise.
Remove each preamp tube one at a time and replace with a known good tube.
If amp works again or noise goes away, mark or discard problem tube and continuing rocking and/or rolling.
If there is still no sound or the problem did not go away, contact repairs@drzamps.com for further instructions.
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Post by Paul (TRANE) on Nov 9, 2015 20:07:34 GMT -7
What I just posted was the trouble shooting section of the Dr. Z Web page. Hope that helps.
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Post by wolfie on Nov 9, 2015 20:38:08 GMT -7
Ok I tried another rectifier tube and its working. Hopefully just a bad tube.
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Post by Paul (TRANE) on Nov 10, 2015 6:53:32 GMT -7
Tubes are the leading cause of issues with tube amps. They just do not make tubes like they used to.
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Post by southmusic70 on Nov 10, 2015 8:04:23 GMT -7
And in my experience it's more than likely the rectifier tube that goes first.
Anybody else?
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Post by Eric from Cheekago on Nov 10, 2015 8:08:37 GMT -7
Ok I tried another rectifier tube and its working. Hopefully just a bad tube. Do yourself a favor and buy a NOS rectifier from a reputable source. A NOS rec will last substantially longer than new production. I buy all my tubes from Mike at KCANOS, fwiw. KCANOS |
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Post by Paul (TRANE) on Nov 10, 2015 11:02:18 GMT -7
Ok I tried another rectifier tube and its working. Hopefully just a bad tube. Do yourself a favor and buy a NOS rectifier from a reputable source. A NOS rec will last substantially longer than new production. I buy all my tubes from Mike at KCANOS, fwiw. KCANOSAgreed. Mike at KCA is the best. Cannot go wrong with NOS. |
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