Dying Pioneer SX-949

[edbar76]

My trusty Pioneer SX-949 is starting to have issues... It will play fine for a while (random times) then I'll get a crashing sound, then the protection shuts the amps down. Nothing. Does this possibly sound like the power supply caps need replacing? If so, can anyone suggest a source? Maybe something is the amp section? Just wondering if anyone else has experienced a similar issue.
Thanks! --Ed (I have a 'backup' 949A which needs a good cleaning..maybe time to break that one out!)

 

[edbar777]

Yep, I replied to my own post. Well almost one year later, my backup SX-949 died. This one blows the power fuse, so I'm guessing something in the power supply board. Out of the two dead ones, this problem may be easier to figure out (I hope !!) Anyone have suggestions on where to start? Bad electrolytics? For now, I'm running two separate 2ch amps off of a Sony SQD-2070 decoder.
Thanks
--Ed

 

[JonUrban]

I know we have 949 owners here. Can anyone help edbar out?

 

[KeithD]

Well Ed, don't know if you solved your problem, or if you are even a member here any more, I do have some experience repairing the QX-949. Your problem (in both cases) is very likely the 2SA726 transistors on the power amp boards. There are two on each of the four channels. They very often go bad and will throw the receiver into protection. Second possible culprit is the 2SC1451 transistor. There is one of those in each of the four channels on the power amp boards. When these go bad they can damage other parts of the power amp circuit and parts of the power supply board. They should always be replaced in any repair/refurb of the 949.