exxos's Atari, Amiga & retro forum

Just arrived and working through the RAM:


Much better selection of tests than my other RAM tester, and good coverage of a wide range of RAM IC's.

Cool little gizmo. Imagine it's a bit easier than trying to diagnose which one out of a bank of 16 chips has gone bad :lol:

exxos wrote: 13 Mar 2026 14:14 Cool little gizmo. Imagine it's a bit easier than trying to diagnose which one out of a bank of 16 chips has gone bad :lol:

100%.

I'd figured out some bad RAM using a thermal camera, it was cold, but it turned out there was another dead one hanging around that wasn't cold.

I now have about 10 dead 2114s, some of which were dead in my OSI610, some of which came with the Atom replica. Luckily I have some good spares.

Good job I got rid of all that ram then :p

I ended up fitting a noisekiller and yaarrb which got rid of a lot of the older components. Never thought of them actually not working as the Atom booted each time.

PhilC wrote: 13 Mar 2026 14:31 Good job I got rid of all that ram then :p

Well to be fair out of what you sent me only 3 were dead, I think that's good odds for 30-40+ year old RAM.

PhilC wrote: 13 Mar 2026 14:31 I ended up fitting a noisekiller and yaarrb which got rid of a lot of the older components. Never thought of them actually not working as the Atom booted each time.

Yeah, I sort of had that with the OSI 600D but it does a RAM test on boot and if the numbers don't quite add up then you can figure out where the bad RAM is.

The Noisekiller and Yaarrb seem interesting though not sure if they run on a replica...

Well, in a flashback to the 80's the Atom decided to die this morning...

It ran first thing but now the keyboard is dead...

Since it is booting to the Atom prompt it suggests the CPU is running the code from the ROM, so that just leaves the 7445 and the 8225 as possible culprits. Which is annoying... Epecially since the 7445 tests just fine.

I'll try a different ROM in case the one in there is bad and it's freezing up, but I have a feeling the lovely 8225 that came in Tandy packaging has died on me :(

This is the fun of building replicas :)

EDIT - I tried a different CPU, different ROMs too, but still no keyboard action, so it looks like a bad 8255 :(

Well, I've managed to order a couple of 8255's for the princely sum of £7, so fingers crossed they'll fix this keyboard problem.

rubber_jonnie wrote: 17 Mar 2026 09:15 Well, I've managed to order a couple of 8255's for the princely sum of £7, so fingers crossed they'll fix this keyboard problem.

Good luck. I might look at getting spares too as it's one that I don't keep in stock.

PhilC wrote: 17 Mar 2026 10:28

rubber_jonnie wrote: 17 Mar 2026 09:15 Well, I've managed to order a couple of 8255's for the princely sum of £7, so fingers crossed they'll fix this keyboard problem.

Good luck. I might look at getting spares too as it's one that I don't keep in stock.

Yeah, bit of an oddity I don't know of much else that uses it TBH. I'm a bit short of a few things. like 6502's, Z80's and some of the associated support IC's like 6522's.

I do need to restock for sure.

rubber_jonnie wrote: 17 Mar 2026 09:15 Well, I've managed to order a couple of 8255's for the princely sum of £7, so fingers crossed they'll fix this keyboard problem.

:crossed1: :crossed2: