Hmmm which one is the driver. Is that the 12ax7 right by the power tubes? And thanks i will check the connector and report back. I know HT bites, thats why Im going to drain the caps EVERY single time unless of course I have to leave the power on to check any components. If that is the driver, then yes, i changed out all seven.
This amp has a lot of relays in the signal path. SK101, SK102, SK103. If it is possible to get to these with the amp on "TAKE care" try tapping each of them and see if the fault appears. They are on page 10 at the bottom. a dirty contact or bad connection can cause this! You could try switching the relays on and off and see if the fault changes. You need to work from output to input through the signal path.
I have to sign off now, hopefully someone will pick this up with you. I will try and catch you later.
Regards
M. Gregg
I have to sign off now, hopefully someone will pick this up with you. I will try and catch you later.
Regards
M. Gregg
What makes you say you have a vacuum leak? The photos of the tubes look OK... Maybe you are referring to the slightly reduced getter in one of the tubes? What makes you suspect there is an issue with a resistor?
You need to take a logical approach to fault finding. A false assumption can lead to expensive parts purchases that may not be required.
What test equipment do you own? A multi-meter is almost a must for fault finding. Some kind of signal source would be helpful too, even if it is just an ipod or similar.
Cheers,
Chris
You need to take a logical approach to fault finding. A false assumption can lead to expensive parts purchases that may not be required.
What test equipment do you own? A multi-meter is almost a must for fault finding. Some kind of signal source would be helpful too, even if it is just an ipod or similar.
Cheers,
Chris
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Hi guys;
sorry I did not chime in before.
Amps that have tubes on PCB often have problems with broken solder joints.
When tubes heat up they get bigger; when cool down they get smaller. A little bit, but it causes mechanical tensions between pins and PCB that damages solder joints when they are switched on/off, on/off periodically during long time. They may look good, but actually they may be loose.
sorry I did not chime in before.
Amps that have tubes on PCB often have problems with broken solder joints.
When tubes heat up they get bigger; when cool down they get smaller. A little bit, but it causes mechanical tensions between pins and PCB that damages solder joints when they are switched on/off, on/off periodically during long time. They may look good, but actually they may be loose.
Chrish, the second tube has a line all the way around the top, and the greyish color is diminished. The tube does not look normal, but IDK. I am simply looking for places to start, not parts to buy without checking them first, believe me the last thing that I want to do is waste money on a lost cause...... : )
Wave, are you suggesting that I reheat the solder joints where the tube sockets meet the board? Or do you think that the tube sockets themselves need cleaning or replacing?
Wave, are you suggesting that I reheat the solder joints where the tube sockets meet the board? Or do you think that the tube sockets themselves need cleaning or replacing?
May be. It happens quite often. But may be something else, like high power resistor that gets hot when you switch on your amp.
So fellas, I checked all the solder joints around the relays, reheat and soldered all the joints around the tube sockets, cleaned and lubed all of the pots/switches and NADA. Still the same crackling noises.
I did however notice, that when I turned the dials, the only one to make any hum was the reverb dial and it hummed pretty loudly, but no crackling, and as I noted earlier, when I play for 10-15 minutes, it sounds like the reverb starts to fade in and out, as well as the sound diminishes. Do you guys think that I should start checking things in the reverb section? Could that be causing the crackling during warm-up?
I did however notice, that when I turned the dials, the only one to make any hum was the reverb dial and it hummed pretty loudly, but no crackling, and as I noted earlier, when I play for 10-15 minutes, it sounds like the reverb starts to fade in and out, as well as the sound diminishes. Do you guys think that I should start checking things in the reverb section? Could that be causing the crackling during warm-up?
Rotus,
The reverb is on page 12 of the PDF file I posted. It just contains the driver circuit for the reverb spring line. The conections to it are on page 10 it says "to reverb page 4". You could just disconnect the send and return and try the amp to see if there is still the problem! The output signal for the output section is from C139 on page 10. The reverb is bypassed by R151 so you should still get a signal and if it still has the problem its not the driver section of the reverb. The reverb level pot would be out of circuit.
Regards
M. Gregg
The reverb is on page 12 of the PDF file I posted. It just contains the driver circuit for the reverb spring line. The conections to it are on page 10 it says "to reverb page 4". You could just disconnect the send and return and try the amp to see if there is still the problem! The output signal for the output section is from C139 on page 10. The reverb is bypassed by R151 so you should still get a signal and if it still has the problem its not the driver section of the reverb. The reverb level pot would be out of circuit.
Regards
M. Gregg
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Soooo M. when the amp was turned on, I was poking around and found that the connector from the power section (the one that you originally told me about) was in fact loose on both ends. I pulled out the fixed input jacks and resoldered the wires to the PCB. I thought this was going to solve it. It solved the problem of the loose connector, but the amp is still doing its little sizzle thing. Also, I disconnected the reverb and same issues. Now I am really lost.
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