Sync tone bleeding into headphones

OK - MPC 3000 LE, working fine. Packed it up, drove 6 hours to my brother's house, plugged in headphones and there's a constant tone like the start of a tape sync signal. I plug the headphone cable in and out a couple times and sometimes I get a modulated tone happening. I check the main outputs and if the headphone tone is constant, the main outs are OK, when the headphone output is modulated, I head a modulated noise in the main outs as well. Individual outs all seem to be good.

This unit has never been recapped (but it's now on the list of machines to do), it has the SCSI PCMCIA reader in place of the floppy drive, and it has the Mansell Labs OS.

Since I don't think I had this problem before (don't remember if I ever used headphone outputs with this MPC before) I'm guessing a component failure, but without the service docs, it's a bit difficult tracing where everything is coming from.

Any hints?

viewtopic.php?f=17&t=109567

There are several links to all of them. so if one doesn't work out, then try thr next link.

Thanks for the link. The megaupload has the 3000 parts list and exploded view diagrams, but no actual schematics. I might be able to use schematics from the other machines to get a general idea (maybe).

Once I get home and have access to my complete set of tools I'll post what I find out.

In the meantime, the search for actual 3000 schematics continues.