No right channel on old Yamaha CR820 receiver - what to check?

LeeH · 10-30-2009, 03:55 PM

I picked up a Yamaha CR 820 receiver that's in super cosmetic condition. The right channel output is almost non existent. The results are the same with different sources (tuner or CD on Aux.) and when using headphones or speakers.

If the volume is turned up then the right channel responds only to the peak (ie loudest) part of the signal. Otherwise, it's silent.

I've hit all the moving parts with contact cleaner with no change. None of the capacitors are swollen or leaking. Anything else to check before I take it back to Goodwill?

aj748 · 10-31-2009, 05:36 AM

Lee,

Nice 50W/ch amp - I had a similar integrated amp I bought in 1981 and it worked well over the years. Is the same channel missing if you use the FM as well as CD/tape/phono? The problem could be in the preamp or power amp stage - some receivers have known weak areas, especially after 20 years - check on line to see if you find anything.

Its best to get a service manual to troubleshoot these. Some manuals are available on-line as pdfs thru various sites and contain component layouts, circuit diagrams, tips, parts lists, etc.

Some receivers have their components and circuit boards laid out in a mirror-fashion which makes it easier to troubleshoot (checking similar points side to side for signal and or voltage until you find the difference). This receiver still has a lot of discrete parts vs. the present day "all in one chip" designs. Previous owner probably received a "courtesy estimate" from a shop that scared him/her off and made it more economical just to buy another receiver. With the right skills and patience, these are fixable! Good luck!

Andy

herr_oberst · 10-31-2009, 09:23 AM

check the circuit board connections to the speaker leads. The slightest crack can render them useless, and it just takes a second to solder it back to working.

After that, can't help

LeeH · 11-01-2009, 07:19 AM

I really have no training in this stuff, but have found my share of obvious prolems when it comes to electronics... loose wire, bad solder points, etc. In this case I have found a bad spot on the circuit board on the amplifier side. I'm going try to put in a jumper to see if that solves the problem. I'f not I'm taking it back. To my untrained eye it appears as if someone has worked on this unit before - maybe cleaning up some solder points. We'll see how it goes.

coolngroovy · 11-01-2009, 01:53 PM

Mine done the same thing...turned out to be a faulty balance pot.

LeeH · 11-01-2009, 03:11 PM

I jumped the bad spot on the circuit board. Got right channel, but something else was wrong as it would come on loud, start squealing then cut off. I'm wondering if the bad circuit was the result of something else being wrong that caused it to overheat. Oh well. Anyway you look at it, it's beyond my skill level and going back to Goodwill.

Think this could have been caused by the two quarters that were floating around inside?

legion · 11-01-2009, 03:30 PM

Well, it's too old for tin whiskers (they still used lead in the solder when that was made). That's my general-purpose explanation for modern electronic failure.

Whisker (metallurgy) - Wikipedia, the free encyclopedia