We spent some time trying to resolve this at Manchester ABUG this past weekend. My initial guess that it was the reset capacitor appeared to be correct and the machine was joyously reassembled after some apparently successful initial testing. Sadly, this proved not to be true - and after some serious head-scratching, it was determined that fitting the backplane (with the metalwork, all screwed in) prevents a clean power-up (but ctrl-reset always rendered an active machine!). Further debugging showed that even just pressing relatively gently on the middle of the board would prevent the startup happening at power-up (but ctrl-reset continued to always work).
Very sadly, this is how we left the machine. My best theory is that the reset pin connection to the MEMC upgrade board may not be making good connection, though I carefully cleaned the MEMC socket and the upgrade board plug, it had no effect. There was some evidence of past strain on the MEMC socket, and my next action (if at home, not on the hoof at an ABUG meeting) would have been to probe said reset signal on the Simtec board and then replace the MEMC socket on the motherboard.
Ultimately, it's still a great machine - an 8MB Alpha - and just needs that extra manual "kick" on power-up to fire it in to life - hence why it was decided to leave it as-is for now.
Very sadly, this is how we left the machine. My best theory is that the reset pin connection to the MEMC upgrade board may not be making good connection, though I carefully cleaned the MEMC socket and the upgrade board plug, it had no effect. There was some evidence of past strain on the MEMC socket, and my next action (if at home, not on the hoof at an ABUG meeting) would have been to probe said reset signal on the Simtec board and then replace the MEMC socket on the motherboard.
Ultimately, it's still a great machine - an 8MB Alpha - and just needs that extra manual "kick" on power-up to fire it in to life - hence why it was decided to leave it as-is for now.
Statistics: Posted by IanJeffray — Tue Jan 30, 2024 1:31 am