Yamaha CR-2020 Help!

OK. The backside of that E-cap board looks pretty bad. Need to remove those two 22Ω resistors. and verify that all the traces have continuity. From one point to the next point. Also need to look over the backside of the other power supply board. Checking for solder bridges , missing or cracked traces and bad solder connections.
Those two " pass "transistors with the little heatsinks will get replaced in one of the service bulletins. But check the solder connections for the ones installed.They run hot and like to unsolder themselves.

Look these bulletins over when you get a chance.

http://akdatabase.com/AKview/albums/userpics/10004/Yamaha CR-2020 Service Bulletin 3.pdf
http://akdatabase.com/AKview/albums/userpics/10004/Yamaha CR-2020 Service Bulletin 1.pdf
http://akdatabase.com/AKview/albums/userpics/10004/Yamaha CR-2020 Service Bulletin 2.pdf
 
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Hm those bulletins seem to point in the right direction. Alright I removed the resistors but found there are no traces left! They were just soldered straight onto the burnt resistors.
 

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Hm those bulletins seem to point in the right direction. Alright I removed the resistors but found there are no traces left! They were just soldered straight onto the burnt resistors.

Oy vey... Why doesn't that surprise me..:rolleyes:

If theres alot of "carbon" between traces it needs to be scraped away. Carbon is a conductor.
 
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I did check out those bulletins and the same two resistors burnt out on mine so I will order the resistors you provided a link for. What would you recommend to replace the regulator transistors?
 
I was just looking at that thread! :D Would I have to get two transistors? What do you recommend I do about the missing traces?
 
I was just looking at that thread! :D Would I have to get two transistors? What do you recommend I do about the missing traces?

Yes, 2 ea.

Probably the easiest way to deal with the missing traces is to use a formed solid wire jumper ," clippings from capacitors or resistors work great", from the component to the next closest solderable point on the trace or carefully scrape the green masking from the intact portion of the trace,"closest to the component" then " tin " it with some solder. Then bent the component lead over ( if its long enough) to solder it to the tinned area.Its not going to look pretty. But it will be functional as long as there are no solder bridges or contact with any other adjoining traces.
 
Alright I will try that. I also found one of the transistors that needs replacement has all three traces lifted :sigh:. But I ordered the parts and will respond in a couple of days with the results! Fingers crossed!:D Thank you SO MUCH for your help! Couldn't have done it without you! Your the man of the year!:D
 
Well I replaced both transistors, resistors, and the three smaller caps and she still smokes.:tears: However I did notice the smoke is from the solder being heated and melting and not from a component.
 
Well I replaced both transistors, resistors, and the three smaller caps and she still smokes.:tears: However I did notice the smoke is from the solder being heated and melting and not from a component.
Probably all that carbon from the cooked circuit board. The carbon could be creating and alternate path for the current to flow.
 
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It smokes exactly like it did before so it still has the same problem. The picture might be hard to tell but is a 33 ohm resistor
 

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That 1000µf/50v cap is installed backwards.
 

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Alright its been awhile and I got around to getting a new cap and installing it correctly. Still has the same problem. However I have a chance to get a free cr-1020 from a friend. He says it powers on fine and the relay clicks but one channel isn't working. So is it possible to replace the power supply in a 2020 for one from a 1020?
 
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