Need help with my CR-820

SaltWaterJim

New Member
The relay will not click on when I power it up. I opened it up and found a transistor that has blown it's top. There was also a resistor that looks like it has over heated and most likly dead. Take a look at my pic, you can see both problems.

Here is where I need your help. Where can I find replacement parts for these two and most of all if I do replace these parts will it fix the issue or are there other problems to look for? Or maybe I should not waste my time and sell it for parts?
 

Attachments

  • Picture 8.jpg
    Picture 8.jpg
    82.3 KB · Views: 48
Your problem doesn't look like a simple 'replace the bad pat with a new part' problem. Something is amiss with the voltages in that circuit. It requires a schematic, troubleshooting, & appropriate equipment (multimeter, soldering iron, dim bulb or variac, etc).

It the unit is in overall good shape then, please don't part it out! At least sell it as a whole parts unit. It's a good receiver. Some good folks should be here in a moment with other good advice...maybe this will turn into a play by play repair thread (if your up to the task).
 
The relay will not click on when I power it up. I opened it up and found a transistor that has blown it's top. There was also a resistor that looks like it has over heated and most likly dead. Take a look at my pic, you can see both problems.

Here is where I need your help. Where can I find replacement parts for these two and most of all if I do replace these parts will it fix the issue or are there other problems to look for? Or maybe I should not waste my time and sell it for parts?

I hate it when that happens. Several small caps in your photo looks like its toast as well. That cloth sleaved component in the back ground don't look very healthy either.
 
Last edited:
I'm thinking just replacing those couple parts probably won't do the trick. Do you know how to read a schematic or service manual ? Parts are available through various sources. Do you have a multimeter ? Do you know how to use a meter?
 
I have a fluke meter and soldering station. I can read schematics too. I have found some schematics on the net but they are not very good quality, hard to read.

I really would not know where to start on this thing other than replacing the parts that I can see are bad. I'm will to try some things and this is an extra receiver I have around.
 
I looked at that but didn't write it down. When I get home tonight I'll have a look and post back. Thanks for your help!
 
I know how to test diodes and looked up testing transistors. Can they be tested in the circuit?

Sometimes. Most times to accurately check they need to be isolated from the circuit.

Here is a list of possible casualties besides the obvious one.
TR715,719,721,723 and 725

D703,705 and 711

R771,773,775 and 777

FR701

All those small electrolytic caps with the shrunken plastic sleeves are and automatic replacement.
Red dots --- caps with shrunken sleeves.
 

Attachments

  • Picture 8.jpg
    Picture 8.jpg
    54.1 KB · Views: 23
Last edited:
Back
Top Bottom