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Yamaha CR 800 - crackle/fade in right channel

Side note: the side where I'm showing voltage between the TP3 and TP5 points is the side with the 2 new transistors on the heatsink. Could they be causing the issue? I installed them the same way the prior transistors were installed, I just added some new thermal paste on those areas when I installed.
 
NTE248 and NTE247. After posting last night I also tried swapping those transistors from the left side to the right side, to see if the voltage would follow. It didn't; the voltage stayed on the left side.
 
I'm officially stumped, and research is not giving me any new ideas. Is it time to quit on this one, or does anyone have any other suggestions? I hate to lose this receiver.
 
I suppose it it could.. What voltage are you reading on the output transistor collectors. They should be equal voltage one being positive voltage and the other a negative voltage. ie. + and - 35vdc ??
 
avionic said:
I suppose it it could.. What voltage are you reading on the output transistor collectors. They should be equal voltage one being positive voltage and the other a negative voltage. ie. + and - 35vdc ??
Click to expand...

I'll give that a shot; not sure how to test the voltage off the collector though?
 
Gr8One1998 said:
not sure how to test the voltage off the collector though?
Click to expand...
Connect your black test lead to the chassis ground. With the red lead, probe the output transistors case (collector) for DC volts .Be very careful not to short the case of the transistor to the heatsink or you will be replacing more fuses.
 
Got it. The transistors on the left side are showing 45/46V. The transistors on the right side, one is showing 2.6, the other is showing 0.
 
After looking at the board closely again, it looks like one of my fusiable resistors (FR701) has some discoloration on it, indicating possible frying. It's toward the bottom of the board on the left side, the same side with the 35V measurement between TP3 and TP5. Does that shed any more light? I'm kind of grasping at straws here, if you can tell.
 
Gr8One1998 said:
After looking at the board closely again, it looks like one of my fusiable resistors (FR701) has some discoloration on it, indicating possible frying
Click to expand...
Gr8One1998 said:
Got it. The transistors on the left side are showing 45/46V. The transistors on the right side, one is showing 2.6, the other is showing 0.
Click to expand...
I was going to say. Check your fuses again. Then check FR701 out of circuit.
 
The fuses are all still good; I pulled FR701 out and it's showing OL when I try to measure resistance. Definitely looks fried in the center compared to the same FR on the other side of the board.
 
So...I put in a new fusible resistor, turned it on and it worked! Was having some scratchiness in both channels, but poked and prodded some of the transistors and got the scratchiness to go away. Everything seemed to be going great, and then well, a resistor caught on fire... (see pic).
 

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