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PL-540 Auto Return

Posted: 28 Oct 2019 01:02
by waxburger
Hello everyone!
After years of lurking and learning I think I might have something to contribute to the community. I couldn't cue up a track on my (original owner) PL-540 in the middle of an LP without the auto-return kicking in, lifting the arm and returning it to the rest.
Here's what I found when I went inside; look at the exploded diagrams on P.24 & P.25 in the service manual. On P24 find PU plate 'B'. See that little arm sticking down on the right? Now on P25 right at the top find the "Lever Unit PXT-250", what was happening in mine was the lever unit had become just loose enough at the pivot-point to lift the tone-arm end high enough to engage that little arm on plate B. I used some 2 sided tape to stick a couple of small brass crown nuts on the lever unit as a counter balance to hold down that end of the lever. Once that was done the adjustment screwhad to be reset but now my 540 works great, except for a strobe issue. It seems my strobe is only half flashing. I've looked at the schematic in the manual and read the related bits in sections 6.3-6.5, and I'm guessing the transistor Q3 has failed? I'm hoping one of you technicians out there might offer some insight on this. ... ervice.pdf

Re: PL-540 Auto Return

Posted: 16 Nov 2019 02:56
by waxburger
Update- Well there was nothing wrong with Q3. All 3 of the electrolytic caps on the power supply pcb were bad, replaced them with new Vishay/Spragues and all is well.