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Yamaha CR 800 - crackle/fade in right channel

Well it looks like R740. According to the shitty, free, SM downloads. 10 Ω 1/4 watt.
Need to clean off all that smoke soot. And test TR714 driver out of circuit.
 
Well, I think I may have fixed it. Tested TR714 (and it's PNP partner on the other side of the capacitor), and both were fried. Replaced those, and replaced 3 burned out resistors, and it seems to be working! I'm gonna put it through it's paces for a couple of hours tomorrow to make sure nothing else bursts into flames, but things are looking up!!

Thanks for all your help avionic; you definitely made a HUGE difference to this project!!
 
Well the good news is nothing has blown/burned up! Unfortunately I'm back to a variation of my original problem; crackly/staticy sound and fading sound. It's a little different than before - originally it was a problem with the right channel, now it's somewhat both.

- Both channels have the issue when outputting through the speakers, and also now when I play around with the volume, the sound cuts in and out when I move the knob
- On the left channel, the issue is present in the speakers AND headphones, but on the right channel, it's only present in the speakers (sounds perfect in headphones)
- I've tried different speakers, and speaker wire, and that doesn't solve the problem
- If I move the TR713 and TR715 transistors on the left side with a wooden stick, it does affect the sound coming out of the left channel, so I plan to re-test those and either replace or re-solder them. That doesn't explain the issues on the right side though
- If I press on the protector relay with the wooden stick, that also affects the sound on both channels

Any thoughts beyond checking those 2 transistors?
 
Gr8One1998 said:
On the left channel, the issue is present in the speakers AND headphones, but on the right channel, it's only present in the speakers (sounds perfect in headphones)
Click to expand...
I'd be looking at the speaker select switch as well as the headphone jack - Again dirty switch contacts or cold solder connections.
 
Spray some deoxit on your headphone plug and slide it in and out of the headphone jack a dozen times or so. See if it cleans up the jack contacts.
 
Re-soldered the relay connections, and notice a bad solder point on one of the transistors, so I fixed that. Right channel seems to be good now, but the left is still giving me a problem. Not getting the same issue with the sound cutting in and out when adjusting volume. The left channel issue is present on both the A and B speaker terminals. The interesting thing is that, when the headphones are in and the speaker selector is OFF, the sound is perfect on both channels in the headphones. If I move the speaker selector to turn the speakers on as well, the issue in the left channel starts to impact the headphones as well as the speaker.
 
Deoxit D5. After a bit more use, it seems to have helped somewhat, but is still a bit static-y. I'll try taking the switch apart and cleaning it really well next.
 
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