If Minerva reports a memory fault due to a broken track, and the track is fixed, might there now be no video (TV says "No Signal") after the memory test, due to a different problem? Or is this evidence the track fix is bad?
If you want to read further, here's the story: My AH 128K QL started failing with white screen after pattern (first intermittently, then permanently) maybe after I accidentally left it on overnight.
I suspected a RAM fault so put in Minerva. Sure enough, the fault was in high memory (IC14) - I seem to have thrown away the actual test result, but in any case if I'd misread and changed the wrong IC I wouldn't expect things to get any worse.Minerva then boots (or used to) with limited memory.
As is customary I then made a pig's ear of IC14 removal, breaking tracks to pins 3 (/WE) and 16 (VSS) in both directions. I put a socket in, got a replacement HM4864P-2, and started repairing the tracks (pin 3 in both directions IC13-14-15, pin 16 only from the left IC13-14 as IC15/16/8 are also fed from the other side I believe).
With 3 fixed on the left but not the right, I get:
70827600
F082F680
00020000
i.e., IC8, as you would expect - as it is missing /WE. However once I fix 3 on the right I get... nothing, no video signal. Suspecting I have shorted something but can't find a short from adjacent pins or anything that may be touching that shouldn't.
So yes, the issue is whether I must have shorted or opened something and if so why there is any video at all before this last step? Does Minerva shut down video programmatically after the memory test (and another fault stops it going further) or is this just evidence my pin 3 fix is a mess? (Worth noting that the result is the same if there is no IC14 in the socket, so the higher bank test should be failing in that case. Instead, no signal.)
If the latter then I have a simpler problem (me). If the former then I have a more complex problem (also me).
