Yamaha R-900 problem

[opossumcrush]

My Yamaha R-900 has a problem. I'll turn it on, I don't heard the relay click. It will play for about 5 seconds and then stop. All the lights are still on. Anybody have any idea what the problem might be?

 

[avionic]

Check and make sure your speaker wires are not shorting together.Otherwise you probably have a bad output module .

 

[PacificStereo]

Very possibly the V-amp.

Avionic, I am not where my manuals are, but I recall the R-900 as having have those output boards, not modules. The 700 had STK outputs, but not the 900.

Am I hallucinating?

BTW, if the 900 IS as I remember, never, ever try to troubleshoot one by running the amp without the output boards installed. It's instant death.

 

[Cogsinister]

I had trouble with my LXI receiver doing just that......i noticed the STK V-Amp had no heatsink and was geting very hot.....i rummaged round and found a heatsink that would fit......fitted it, and the amp will run all day long with no cut-outs......

 

[PacificStereo]

Yeah, a lot of people believed Sanyo when they said, "Not need heat sink."

Now that I reread this, I'm confused about something else too. If the unit doesn't come out of protection, how can it play for five seconds?

 

[merrylander]

AFAIK the 900 does have STK outputs, just higher power than the 700. It is the 1000 and 2000 that have the Sanken power amp boards.

 

[Jon_Logan]

Doesn't this one require (or benefit from) installing the 100uF caps into the shunt legs of the NFB loop?.


Hated the IGOxxxxxx STK V-Amps. *poof* $50. hard to stock enough.

 

[opossumcrush]

My mistake, it does come out of protection. and then shuts off a few seconds later. It will set for about 15 mins, and do the same thing. No touching speaker wires, I'm using pin connectors. I've tried two different sets of speakers.

 

[avionic]

Sounds like you have a device that is not thermally stable..Could be one of the power packs or a number other things.Like a power regulator for the module.May need some freeze mist to locate the offending component.

 

[Jon_Logan]

I believe the offending part will the the V amp. Those things don't require any support circuitry to be bad to show a problem. They fail all by themselves.

 

[aileenamegan]

Might be also helpful to clean or replace the relay. Could cause these problems.

If it is right from the start, even if it's in a cold state, then it shouldn't be a thermal prob.

 

[Jon_Logan]

If it is right from the start, even if it's in a cold state, then it shouldn't be a thermal prob.

Some things fail after a change in temp.

 

[aileenamegan]

Some things fail after a change in temp.

Thats right. I thought of parts getting warm and then failing...

 

[PacificStereo]

Thanks, Merrylander. It's been a while since I had one of those apart. Stuff can get jumbled in the old brain after 20 years (WHOOSH! "What was that?" "That was your life, mate.")!

Possum, it's almost certainly the V-amp. I would start by changing that, and if it does not already have a couple of 50-100 uF caps soldered to the bottom of the board, there's a DC mod that needs to be done to it, as well. We can help, once you get to that stage.

 

[merrylander]

I have an R-1000 sitting here waiting for me to figure out why one amp won't adjust idle current, PITA.