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Pioneer RX-570

I have an RX-570 here that keeps popping the outputs and have no clue where the SM Transistors are to defeat the BLOW Line in it. According to another post I read, Q7401 and Q7406 are the SMTs in question, but they're not on the amp boards, are invisible or I'm going blind. The entire amp module is brand new, so you can imagine I was pretty suprised (enraged really) when I fired it back up and it killed the thing. I had a 100w light bulb in there to keep it from self destructing as well, but it didn't help.

I want to rule the entire amp module out, since it was new and still got toasted. I replaced the outputs and the 220ohm resistors are all still good on it. But now really have no clue where to start looking externally for whatever is kicking the "protection circuit" (term used very loosley) on. Every other one I've ever messed with had open resistors or shot outputs and that repair alone fixed them up, but this things deciding to be a nightmare. If you have any ideas or info I thank you a ton in advance.

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RDC
Reply to
RDC
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There are really some of those piles of crap still out there?

Reply to
dkuhajda

It seems that a factory mod (approx $250) is required. "Better off in the dustbin".

See

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Reply to
Ross Herbert

The surface-mounts are there - they are just hard to find. A nagnifying glass helps to find the board markings. These units can be blown by a bad cassette motor or any power supply voltage being low. When you find 7401 and 7406, short the E-B junctions.

Mark Z.

Reply to
Mark D. Zacharias

Yep, and you wouldn't believe how attached to them some people are. I can understand the attachment to a piece of electronic equipment, but not to a crappy one. Some people figure because it cost close to $1000 when they got it 12 years ago that it must still be worth that much. Those two things combined make for a "hard to steer down the right path" type of person. So they'd rather have it fixed than listen to reason and put that money toward a nice receiver.

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RDC
Reply to
RDC

Thanks Mark, I was hoping you'd see this since it was an older post of yours that had the info. Are you saying these are on the Front amp board? or are they located elsewhere? I've been all over both amp boards and there are no Q74xx at all on these, Q71xx and Q72xx on the Rear/Reg/Protect Board, and then Q75xx and Q76xx on the Front Board.

Thanks again.

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RDC
Reply to
RDC

They're there, just almost impossible to find. One in on the front amp board, one on the rear amp ass'y. I'm not quite sure how to steer you to them. I have a couple similar modules laying around at work, but I'm not sure if any of them are from a 570.

E-mail my work e-mail direct at:

snipped-for-privacy@labolgcbs.net

and reverse the domain name.

Maybe I can take a pic and e-mail it to you.

Mark Z.

Reply to
Mark D. Zacharias

Email sent, I attached pics of the boards I'm dealing with also.

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RDC
Reply to
RDC

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