sony receiver has gone dim on the right channel

[Derek]

Mid winter the right track started to simply almost disappear (I say almost as putting my ear right up to a speaker I could still tell what song was playing as some signal was still getting through.) If I got up and tapped the case it would come back on fully. This worked for about three months, then I'd have to get up more often and tap the case, then it was every three minutes. At which point I was starting to get really annoyed, so I took it apart. I sprayed contact cleaner in the balance and the volume knob and looked closely for a pin that the cold solder might have pulled away from. I found nothing wrong.

 

Sony STR-AV910 is the model #. It is from 1989.

 

I really like it as it has an actual EQ and not just bass/treble or those stupid jazz/rock/talk, etc. settings.

 

I hesitate to send it to a repair shop as once you ask them to fix it, you could end up with a bill 2/3 as much as buying a brand new unit. But since nothing available new has more than bass/treble, I would be willing to put a fair bit of $ into it. Plus the new ones mainly don't have any way to hook up my turntable which is a must for me to be able to use. The temporary replacement I borrowed is nice, but no record player hookup is possible.

 

On a related note, how does one utilize the speaker B button? I have hooked up speakers to it, turned A off, tried both on, nothing makes the speakers hooked up to the B button work. Doesn't matter what ohms or impedance I hook up either. I'd like to run just two speakers on the B button so that late at night I know that the neighbors won't be bothered by too much noise passing through the walls and into their mobile home/trailer as we are quite close together here and when there is no wind the tunes really carry through the still night air even at a really low volume.

 

Thanks for any constructive thoughts!

[Trinity]

It probably has a blown final transistor or STK package.

[Derek]

It probably has a blown final transistor or STK package.

Care to elaborate on what either of these things are or whether either are fixable or replaceable for a reasonable $ amount?

[Trinity]

http://www.made-in-china.com/showroom/chaida/product-detailTMrJZOFlCAYW/China-STK4192II-Series-of-STK.html

 

 

Fixable, Yes. But it will cost ~35-45 for a stk. Or about 5 bucks for a final transistor. If that's what it is.

 

Use google...

 

See this image,

[bust3dstr8]

Tapping on electronics to get them working is often a sign of bad joints. You checked the balance and volume, but the problem could be in

the right channel amp circuit. Look for bad joints, bulging caps, cracked/blown transisors, burnt resistors...etc

 

You will see lots of talk about changing caps in these forums. Electo caps are good for about 15 years before they start to degrade

and a lot of items we own are now well past that time period.

If they are run hot, like in a reciever they will degrade much faster.

 

You can try changing the caps in the right channel and see if that helps....it shouldn't cost too much for high temp audio grade parts.

If that helps you can justify recapping the power section, the other channel and the rest of the electro caps.

Edited April 7, 2012 by bust3dstr8