Studer A80 repair 140110

Jake Swanson came in today to repair an issue with the 16 track's counter. I've had some rough luck figuring out the issue.

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First, the autolocator took a dump after I returned from a vacation last summer. That's right, I've been using tape every day for half a year or more with no autolocator or counter function. It's no biggie, just listen as you rock ff /rvrs back and forth a bit to find the start, then use edit mode to really nail down where the first note hits.

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My friend Tony had a go looking at the interface power supply for the autolocator and found proper voltage readings. Perhaps the little keypad itself is faulty? He discovered the molex connector on board the Studer's transport counter cards was not making contact, developed a work around and the counter showed all zeros but no actual counting function.

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When I bought the 4 track 1/2" A80, I thought I would be able to figure out the counter problem by swapping cards from one machine to the other. All I managed to do was to cause smoke to billow out of the area of interest. Great. I've ruined the counter function on both machines. I learned some stuff along the way, but it caused more issues.

I recently found Jake Swanson and he came in a few weeks ago to try his luck figuring this counter issue out.

After Jake had a go repairing the basis board and checking voltage readings across the 2 other counter boards he discovered a grounding issue. With ground floating, voltage readings where twice what they should be. So, instead of 5.8 volts pos and neg, he was getting 10! He found the molex connector supplying the basis board was faulty at one pin (the ground), he re-tightened that sucker and viola, perfect voltage readings everywhere on all 3 counter related boards. Still no counter function.

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Jake texted a friend at ATR Magnetics who pointed us to the e-prom chip. This is a programmable chip that decodes and clocks the counter. Or something like that :/ Apparently these chips fade over time and lose the original programming. Jake is under the impression that we need a replacement to move forward.

Now, where to find an e-prom chip that fits these Studers?

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