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Bottlehead Forum Welcome! Need support, you got it. Or share you ideas and experiences. |
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Bottlehead Forum Welcome! Need support, you got it. Or share you ideas and experiences. |
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In Reply to: seeking sharp troubleshooter (foreplay + paramour Q's) posted by yd on September 20, 2000 at 19:24:37:
"...Foreplay... Signal surges up again if I adjust the sweet whispers or just tap on the case..."My guess: short circuit or bad tubes. It could also be something very straightforward. If after swapping tubes and things didn't improve much (meaning that tubes are probably working fine), use a multimeter and follow through my voltage/resistance verification test in my web page (see Loose Page). Reheat solder joints if necessary.
"Paramour. One of the amps no longer makes any music, just a nasty humm/buzz even when fed no signal. The 2A3 and the 12AT7 are both about half as bright as their counterparts on the working amp, but I think that this may be a red herring as they were dimmer before when working..."My guess: If you didn't blow any fuse and they are only half as bright and 2A3's plate doesn't glow red then chances are you might have an open or shorts somewhere. If, after swapping tubes things didn't improve then yes, follow through all the usual diagnostic procedures such as resistance/voltage check and also reheat solder joints if necessary. Also desolder parafeed choke, output coupling cap(aka parafeed cap) and output transformers for resistance readings. FOr both transformers you should see resistance reading of somewhere between 30~200ohms, and no resistance reading for caps (only a minute swing if you have an analog meter set to Rx100 or Rx1K).
Also check the transformer winding part for 6.3V AC and 2.5V AC readings. Check B+ part for something like 280V AC *2.
Check 12AT7's plate for a voltage reading (should be something like 100V DC or more). Check 2A3's plate for voltage (250V DC or similar. If you do not see any of these readings obviously your power supply side is bad. Proceed from there...
Reheat all solder joints if necessary.Good luck!
Quest ;^>
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- Let me guess... - Quest 00:38:11 09/21/00 (0)
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