Yamaha CR-2020 no sound

super j

Active Member
I came home yesterday with some beer and the intent to spend the evening spinning some tunes. No sound output from my receiver. To top that off, I brought out my back up amp, a Yamaha AX-550, and found that it no longer works. A very disappointing friday evening.

As for the CR-2020 there is no sound output and I do not hear the relay turning on. I've been reading a few threads looking at possible problems. Any suggestions are appreciated.

I did remember that I picked up a technics SA-111 for $5 at goodwill a few months ago. I haven't tested it yet, so hopefully I'll have this as a back up.
 
Does the tuner meter appear to work while trying to tune in and FM station ?
 
On the rear panel. Decoupler/coupler switch. Decouple pre-amp from the power amplifiers. See if you get a power on " click" now.
 
Yes to technical ability and tools. I just don't have much experience troubleshooting audio equipment. The lamps light up. Tuner meters move when adjusting tuning. No relay clicking when I toggle the coupler switch.
 
Super...Download a copy of the service manual.

Locate R741 and R742 on the power supply/relay board. Measure the DC volts at both ends of each resistor. Ideally there should be zero volts (dc offset) . A few millivolts most likely. Problem if more than 1 volt .
 
Do you know if the service bulletins have been done on this unit ?
 
Also . Measure the collector voltage on the output transistors ( the metal outer casing is the collector on a TO-3 transistor.) Should be roughly + and - 49vdc. rail voltage.

Be careful not to short the metal transistor case to the heatsink( chassis ground ) <------- bad juju..
 
Thanks for your help. I have errands to run so I'll have to get back to it later. I'm pretty sure the service bulletins have not been done except for number 2 . I soldered the jumper wire in while I had it open for something.
 
Yeah, for R741,2 avionic is checking for any significant Vdc in which case the relay will not be operated so as to protect the speakers, so no sound.
Measure between resistor and GND, then repeat for other end of resistor.
 
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