This one is on the bench with external keyboard hooked up. The RTC area and ROM sockets have been reworked (by me). It's got 3.11 ROMs.
I had got it to the stage of seemingly working fine. The Desktop comes up the RTC keeps time etc. However, fitting a RAM expansion on SK16 seemed to have killed it (no display, keyboard not working). Out with the POSTbox - nothing. Checked that power is getting to everywhere, checked the ROM address walk with reset held in - that's OK. Took off the RAM expansion (which is a very tight fit), still nothing. Start doing all the continuity checks for the ROMs to ARM - all OK. Then it starts working again!
So it's some intermittent break - but I've no idea how to go about finding it. Fitting a RAM expansion (works fine on another A3000) kills it again Image may be NSFW.
Clik here to view.
Removing the RAM expansion doesn't revive it.
It's now in the dead state, so, what should I check ? Address walk with reset held in - that's still OK (although there's nothing on the data lines). ROMCS is active. I've checked continuity between MEMC & VIDC clock & control lines, all looks OK, as does RAM CAS, RAS and bank select. Any diagnostic suggestions (except for poking it until it works again) gratefully received.
I had got it to the stage of seemingly working fine. The Desktop comes up the RTC keeps time etc. However, fitting a RAM expansion on SK16 seemed to have killed it (no display, keyboard not working). Out with the POSTbox - nothing. Checked that power is getting to everywhere, checked the ROM address walk with reset held in - that's OK. Took off the RAM expansion (which is a very tight fit), still nothing. Start doing all the continuity checks for the ROMs to ARM - all OK. Then it starts working again!
So it's some intermittent break - but I've no idea how to go about finding it. Fitting a RAM expansion (works fine on another A3000) kills it again Image may be NSFW.
Clik here to view.
Removing the RAM expansion doesn't revive it.
It's now in the dead state, so, what should I check ? Address walk with reset held in - that's still OK (although there's nothing on the data lines). ROMCS is active. I've checked continuity between MEMC & VIDC clock & control lines, all looks OK, as does RAM CAS, RAS and bank select. Any diagnostic suggestions (except for poking it until it works again) gratefully received.
Statistics: Posted by cjed — Tue Mar 18, 2025 12:19 pm
