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Trouble with Marantz 2226b

Q1-Q4 on the amp board are 2SA750. Replace them. While you have that board out, replace Q705-708 MV-13 diodes each with one pair of 1N4148 or 1N914 diodes in series, comb it for cracked solder joints, and apply new thermal compound to the output transistors. If the problem persists after those things are done, we will have to troubleshoot it further.
 
tarior said:
Q1-Q4 on the amp board are 2SA750. Replace them. While you have that board out, replace Q705-708 MV-13 diodes each with one pair of 1N4148 or 1N914 diodes in series, comb it for cracked solder joints, and apply new thermal compound to the output transistors. If the problem persists after those things are done, we will have to troubleshoot it further.
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I see! Just did a bit more testing with the amp. Pushing in the mono-switch stops all other noise. Don't know why I hadn't noticed that before. Of course, now all inputs are in mono, so it's not a final solution. I've cleaned all the switches several times with deoxit now, including the mono-switch. Could this information pinpoint the problem anymore? When the mono-switch is off/out, switches before it in the circuit, like the input-selector, still makes noise
 
Thanks for bearing with me! And sorry for all the back and forth! Before I go about opening the switch: this could be the issue? Could a bad connection in a switch cause switches before it in the circuit to make pops?
 
I've never seen a switch do that, but there's a first time for everything I guess.
 
old thread new thought. i'd use deoxit d100 on the tape monitor switch. it's an ultra common problem with these. usually when guys start fishing and pulling stuff and soldering beyond a reflow it's rare less than an experienced tech gets it all the way home, you don't need to redo the guts usually. it's always oxidized switches with these. this is why d100 is a must. it's pure deoxit. too harsh for potentiometers but great for switches, jacks, and batteries. once applied it works forever. with deoxit d5 on the potentiometers, you've got to reapply about every 2-5 years.
 
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