Yamaha CR-1020 Won't Come Out of Protection

[HypnoToad]

I have a pristine CR-1020 that was working fine last time I used it, that was 2 years ago, I have since moved back to Australia and got it out to day to put in in a bedroom system.

I have two different proper step down transformers that work with everything I have tried on them, 1 x 1500 watt and 1 x 500 watt, I thought the 500 watt would be plenty, plugged it in lights come on but no click. Tried it with the 1500 watt same thing.

All the buttons seem to work as the leds come on and off for FM etc.

I got it to click in once but turned it off before I connected speakers etc and it wouldn't click in again. Is it possible something came loose inside in transit, or just rough handling although the shipping people seemed first class.

What's the place to start on checking it out?

I just removed the chassis and noticed the relay on the front left was not aligned properly, the plastic cover was not on properly either. I removed the cover and aligned the contacts. Not sure if this happened when I was sliding out the chassis but I tried it and the relay clicks in now, but a couple of times it clicked in and out, I just sprayed it with contact cleaner and will try it again after lunch. I will also check the idling current of the main circuit board. I checked the idling current and both channels were in spec, 9mv's I set them both to 10mv's for the sake of it.

Any help would be appreciated.

 

[M@tt]

Have you measured the voltages on the various pins for power take off i.e. Lighting, aux power, etc? My 2020 was having problems with power to the relay 25v. I think it is several cracked traces on the 25v transistors.

 

[HypnoToad]

Have you measured the voltages on the various pins for power take off i.e. Lighting, aux power, etc? My 2020 was having problems with power to the relay 25v. I think it is several cracked traces on the 25v transistors.

Thanks for your input, I will check those, and I notice a few of the electrolytic's on the PCB with the relay have their plastic shrouds stretched, the tops don't "seem" to be bulging but maybe they have overheated, I'll replace them all and see what happens.

 

[bobca]

I used my CR-1020 effectively with power conversion transformers while living in China for several years. I had no issues then. Age has finally caught up to the receiver, as it always does. I am refurbishing the power section presently, & I need to work on an issue with my pre-amp board, as the right chanell is not putting forward a signal to the amp. Fun project, but involved, as so many have mentioned.

 

[mbz]

The pupose of the protection circuitry/relay is to protect the spkrs from high levels of dc voltage, normally
anthing greater than about 800mV-1200mV should be viewed with concern.

The relay won't activate if
- too high dc on spkr line
- fault in protection circuit
This could be anything from tired caps, toasted/tired resistors, bad solder joints and... and...

First step is to find the cause in your case.

Down load the service manual from hifi engine

Measure the dc voltage at the brown and then the yellow wires to the power supply board.
This will be the board with the relay mounted, there will be markings on the screen print
where the wires connect, LI, RI (left/right in)

Happy that you replace any suspect caps.

 

[mbz]

anthing greater than about 800mV-1200mV should be viewed with concern.

Ooops, should have said "would trigger the protection circuitry".

As for dc offset, some manufactures quote 0-100mV as being within spec.
I'm sure we would all be strivibg for 0-20mV

 

[avionic]

I'm sure we would all be strivibg for 0-20mV

Or less..