Service bulletins are to replace 2 each 22 Ω/3.25 watt and 2 each 33Ω/3.25 watt. As well as rewire the convience AC plug. And replace the power supply pass transistors. I've done all three mods many many times.
CR-2020 Repair Advice
- Thread starter sajjad amer
- Start date
Those two were not part of the service bulletin.
And personally I would not have used 5 watt resistors for the service bulletin. There is very limited space where the 22Ω & 33Ω ( service bulletin) reside and the 22 Ω's are suppose to be fusible as well.
http://sportsbil.com/yamaha/cr-2020-servbull1.pdf
http://sportsbil.com/yamaha/cr-2020-servbull2.pdf
http://sportsbil.com/yamaha/cr-2020-servbull3.pdf
Last edited:
These are the exact Recommended SB resistor replacement Ohmites.
https://www.mouser.com/ProductDetail/Ohmite/93J22RE?qs=sGAEpiMZZMtbXrIkmrvidIY3c6LmoosbW8%2bArvubKUE=
https://www.mouser.com/ProductDetail/Ohmite/93J33RE?qs=sGAEpiMZZMtbXrIkmrvidNoLDMO5CJt8WrVD/BNh/hc=
https://www.mouser.com/ProductDetail/Ohmite/93J22RE?qs=sGAEpiMZZMtbXrIkmrvidIY3c6LmoosbW8%2bArvubKUE=
https://www.mouser.com/ProductDetail/Ohmite/93J33RE?qs=sGAEpiMZZMtbXrIkmrvidNoLDMO5CJt8WrVD/BNh/hc=
Last edited:
Goldie99
Super Member
Sorry avionic - I most certainly didn't mean to question your experience in any way, quite the opposite - I was simply confused by the earlier reference to 22R max 1/2W (post #3), I took that to refer to what was needed for FR801 & FR802, not what was being replaced.... and subsequently 'lost the plot'.... good job there's a Dr. in the house 
sajjad amer
Active Member
I have finally got the protection circuit board recapped. Good news is relay is clicking, but still there is no sound. The relay is clicking immediately when I flick the switch, it is not clicking like it should. I have checked capacitors twice, they are in right polarity. Where have I gone wrong can you please guide me? Thanks
Look over your solder connections for solder bridging. The relay driver transistor may be shorted E-C.(TR702)
Last edited:
sajjad amer
Active Member
spot on, cleared the solder bridge and now back to square 1, lights are back on, signal quality meter has gone back to zero, but no relay click and no sound.
sajjad amer
Active Member
Coupler switch is set to on, speaker selector switch is set to A and wires are plugged into A.
Need to check the output of each amplifier for the presents of DC voltage.
sajjad amer
Active Member
I have checked and readings are as follows
Speaker selector switch to A-- and measuring voltages on speaker A terminals L+R = 0 volts
However
When I put the probes on speaker B or C it reads -28 mV
And
When I select speaker selector switch to B or C the reading goes back to zero
Can't use the speaker terminals if the relay is not clicking. Have to measure the output on each amplifier board before the protect relay.
sajjad amer
Active Member
Do I need to measure it at orange and blue wire ?
sajjad amer
Active Member
Left Board measures 6.66mV and Right Board is 8.81mv
Thats a good sign. .So that means the problem is in the protect circuit or the protect circuits power supply. Not enough DC at the output to trigger the protect circuit.
sajjad amer
Active Member
@avionic you are the man. In the following thread you mentioned capacitor was installed incorrectly and I had the same issue.
http://audiokarma.org/forums/index.php?threads/yamaha-cr-2020-help.663359/page-2
Now when I switch on the receiver relay clicks after 10 or so seconds (quite long time). BUT still no sound.
I removed each and every transistor off the relay board and checked with transistor checker, they all check fine. I have also Re soldered the whole board.
I get no reading neither between TP1 and 0 nor 0 and E on both amplifier boards.
http://audiokarma.org/forums/index.php?threads/yamaha-cr-2020-help.663359/page-2
Now when I switch on the receiver relay clicks after 10 or so seconds (quite long time). BUT still no sound.
I removed each and every transistor off the relay board and checked with transistor checker, they all check fine. I have also Re soldered the whole board.
I get no reading neither between TP1 and 0 nor 0 and E on both amplifier boards.
What position is the coupler switch on the rear panel in ? Speaker select switch in the proper position?
Mute switch disabled ?
Last edited:
