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Pioneer SX-590 DC Offset

J

JRJOP

New Member
Hi all, I have recently acquired a SX-590 receiver which I would like to restore and put back to use. The unit lights up and the VU meters move etc but I have a very high DC offset of around 28.2VDC.

I have checked through the boards for dry solder joints etc. I have also replaced the suspect resistors at R401, R403 & R347. I also read that transistor Q402 could cause issues and I have replaced this also.

Where should I be checking next as the very high DC offset is still present? Could it possibly be the Darlington STK-0029 modules?

Thank you
 
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Goodness that is high. Welcome to AK.

It might be helpful to have a pic of the layout, I will attach what I found online. It might help some people point out an easy answer for some tests. I don't know very much about testing STKs, but I know they can be tested. Have you used the search box above and queried "Testing an STK-0029". I think testing your STKs with a meter would be a great thing to do, if I recall it's not too tough to do. If you are lucky and they are fine you likely have another semi that is pulling the STKs output to the extreme.

CaptureSX590.JPG
 
Warren-Oates said:
Goodness that is high. Welcome to AK.

It might be helpful to have a pic of the layout, I will attach what I found online. It might help some people point out an easy answer for some tests. I don't know very much about testing STKs, but I know they can be tested. Have you used the search box above and queried "Testing an STK-0029". I think testing your STKs with a meter would be a great thing to do, if I recall it's not too tough to do. If you are lucky and they are fine you likely have another semi that is pulling the STKs output to the extreme.

View attachment 2984210
Click to expand...
Thank you for your reply.

I’ve just swapped out R717 & R718 and the DC Offset has dropped to just under 100mv so I think that was the cause of the issue
 
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