Yamaha CR 220

J

Jodyb

Active Member
Just wondering if anyone has had this same issue with there cr220 Amp.
I'm reading 25 volts DC on both right and left speaker connections. I did a good visual inspection of the caps. Nothing obvious leaking or swelling.
Any suggestions would be appreciated.

Cheers Jody
 
Register to hide this ad
Looks like there is three or four fuses inside.. Check them with a multimeter..
 
A few pictures
 

Attachments

  • 16358133851021072899623656685329.jpg
    16358133851021072899623656685329.jpg
    125.8 KB · Views: 25
  • 16358134101502979704233305600504.jpg
    16358134101502979704233305600504.jpg
    129.5 KB · Views: 30
Unplug the unit..Then pop out those 3 fuses and ohms check them with your meter.
 
After checking the fuses. Need to check a couple power supply voltages.

upload_2021-11-1_19-46-17.png

C805 and C806 the two large gray 4700µf electrolytic capacitors..

Black test lead to the neg. side of C805 and red test lead to the pos. side of C805..( + 25 vdc ) Move the red test lead to the neg. side of C806. ( -25 vdc )..
 
I pulled off the bottom plate measured the voltages on 805 first it is closest to the faceplate and the voltage is +25.43 negative on negative positive on positive. Then positive on negative of 806 and its -25.40.
 
Good.. Now find TR713 and measure the emitter,base and collector voltages.
 
Thanks for taking the time and being so patient I have voltage only on one side of the transistor. Positive on the transistor and ground to the amp body. I'm not sure what one is the collector and emitter. The voltage I'm seeing is on the left side only of the transistor looking at the flat side (numbers) of the transistor its showing 20.15 dc.
 
Left to Right ECB
2sa659.jpg
 
Ground your neg meter test probe to one of the negative speaker binding posts.

upload_2021-11-1_22-4-47.png

Emitter -- - 22.4 vdc
Collector -- - 23.7 vdc
Base --- - 23.2 vdc
 
TR802 emitter +28 vdc
upload_2021-11-1_22-16-28.png

2SC1175 ---> same pin out as TR713

Left to right ECB
 
Avionic thanks again for the help.
So the measurements on TR713 e is 20.1vdc and both both C and B are 0.7 dc voltage and gradually decreases. I removed the 1000uf 35 volt capacitor and tested it reading 0.800uf.
Values on TR802 at the on E 29.05 C is 41.55 and B is 29.6.
 
Jodyb said:
TR713 e is 20.1vdc and both both C and B are 0.7 dc voltage and gradually decreases. I removed the 1000uf 35 volt capacitor and tested it reading 0.800uf.
Click to expand...
Check D805 and D806 ...

upload_2021-11-2_21-55-51.png
 
So I removed the capacitor and it measures good had to change the scale on my meter. (1200uf)
I also checked voltage on both 805 and 806 both came back at 19.92 volts AC I'm assuming it is supposed to be AC.
I went back to TR713 and still only have voltage to E 20.1 volts DC and no voltage to the C or B. I also checked voltage to the 1000uf 35V cap and it is not receiving any power from 713.
I'm think that TR713 is dead and just wondering what a good replacement would be. It's currently a A659 transistor. Could you recommend one?
 
Jodyb said:
I also checked voltage on both 805 and 806 both came back at 19.92 volts AC I'm assuming it is supposed to be AC.
Click to expand...
One end is AC the other end is DC.. By checking diodes. I meant , diode check with your multimeter. Diode check function on the multimeter.
Jodyb said:
went back to TR713 and still only have voltage to E 20.1 volts DC and no voltage to the C or B. I also checked voltage to the 1000uf 35V cap and it is not receiving any power from 713
Click to expand...
The capacitor and the transistor get there DC voltage from D805/806.
 
You must log in or register to reply here.
Back
Top Bottom