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1 (A13) Busy, square waves 2 (A14) Busy, square waves 3 (A15) Busy, square waves 4 (P2) Low 5 (R1) Low 6 (R2) Low 7 (P1) Low 8 (/MREQ) Busy narrow square waves 9 (/RD) Busy, narrow square waves 10 (GRND) 0v 11 (?) High 12 (?) Low 13 (/RE-CPM) High 14 (->/CAS) Busy, narrow square waves 15 (NA15) Sin...

I'm home now. I've programmed a GAL with the 3 ROM & 64K RAM JEB file from Andy's site, fitted it and the ROM select line is still constantly high. The address lines are active as is the _RD line but no ROM select. What's the logic used to generate the ROM select for ROM A? Maybe I'm missing so...

I'm home now. I've programmed a GAL with the 3 ROM & 64K RAM JEB file from Andy's site, fitted it and the ROM select line is still constantly high. The address lines are active as is the _RD line but no ROM select. What's the logic used to generate the ROM select for ROM A? Maybe I'm missing som...

Thanks. There are .eqn and .jed files on Any Key's web site for all the GALs as well, not that I know what to do with them. :-) P.S. The files in your ZIP file look to be for a two ROM MTX500. I'm going to have to get the settings for a three ROM MTX512 now as I've upgraded the memory and change LK6...

Excellent! The GALs have arrived a couple of days early.

Yeah, maybe.

Thanks. I did try ordering one from Retroleum a couple of days ago and got the automated e-mails confirming the order but nothing afterwards. When I previously bought some memory from there it was quite quick. I may cancel and order one from Mutant Catapillar Games. He's definitely reliable. P.S. I'...

I take it that the test ROM contents can go on an EEPROM and go into the ROM A socket?

I've made the motherboard mods for the EEPROMs, written the data to the EEPROMs and fitted them... No difference. The GAL arrives on Monday. I can spend the weekend getting the PAL board operational again. I've got the transistors for Q1 and Q5, which were close to where the crocodile clip bounced, ...

Well, I've started the mods (removed sockets and cut tracks) for the use of three eeproms now, as described on primrosebank. I've ordered some more sockets as two of them fell apart when I de-soldered them. I should have everything except the GAL by the weekend, then I'll have to wait for that to ar...