Restoration Help Yamaha CR-820

sajjad amer

Active Member
I bought CR820 from ebay. It powered up, relay clicked but there was no sound at all to start with.

I Replaced most of capacitors which looked swollen, De-oxidised the fuses, contacts on controls, opened up and cleaned relay. Checked all 4 transistors on side , they are fine, cleaned and re-seated them.

After all this work when I switch it on, its dead. I have checked that there is 240v at primary but I can not measure any voltage at secondary, or should I say I do not know how to.

There are 2 red + black wire and 2 orange + blue wire. I have measured AC Voltage between red & Black, Orange & Blue but it just reads zero. All these wires are wound to a metal contact on board not soldered. Should I remove the wires before measuring?

Can anyone please guide me how to proceed next? Should I just purchase a new transformer?
 
Check both speaker A and B -- make sure you have the correct speaker button selected.
 
Update so far, I managed to restore power it was a broken wire on main power board. Relay clicks intermittently. 7/10 times it does not click, if i keep pressing the power button I do hear a click. But again no sound at speaker terminals. I have measured voltages at orange coloured coils, one coil measures 0 volt and other 19 v. I have removed 4 transistors on side and checked, all 4 check perfect.
I have double checked and correct channel is selected. Please help how to investigate it next , thank you
 
Does your FM meter and LED's appear to be functioning correctly ? While trying to tune in a station ?
 
Need to see if your pre-amplier circuits are getting the correct supply power.
 
Measure the collector voltage of TR609 and TR610. We are looking for the same 30 vdc (ballpark) at both collectors.
 
Relay clicks intermittently. 7/10 times it does not click,
Are all of your incandescent lamps illuminate ? Did you replace C804 ? (33µf/16vdc) Probably a violet colored cap with reddish print...
 
None of the lamps glow, I am waiting delivery of new lamps. I did not replace the 33uf 16v cap as I did not have it in stock at time of recap.
 
Back
Top Bottom