ADM-3A question

After hanging vertically for 36 hrs in a hot upstairs room, more goop seeped out from under the keyboard. It now works again. Whew. While running on the bench for burn-in testing, a cursor problem suddenly appeared... it would only move every other keystroke. With the technical description and schematic at hand, it wasn't hard to track down a 74LS193 up/down counter with a blown (floating) LSB output. Confirmed by manually toggling that bit and the cursor would move back and forth one position. Meanwhile I removed the bad chip and put in a DIP socket. Naturally my TTL collection didn't have an 'LS193 so I'm waiting on that. So I have a 24 line, 1 column terminal :) The monitor was occasionally intermittent (no display at all, no HV, +15 and drive signals OK). It seemed to change with movement of the wiring harness its PCB and it seemed to be fixed - but then the VERTICAL deflection collapsed and tweaking the height adjustment caused increasing loss. The 100 ohm pot to the base of the vertical output transistor had picked that moment to go open. Changed that out and readjusted everything - so far so good after another hour of run time. This ADM-3A could have been unpowered (and in a storage area without climate control) for a very long time. I wonder if that contributed to the failures I'm seeing... hope there aren't any more until I get to use it for a while on my PDP-8/A (or 11/23+). --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus