exxos's Atari, Amiga & retro forum

Let's hope it's a case of plugging the new ICs in and then off you go. What were the faulty ones? I seem to go through 74157s and 257s at the mo

PhilC wrote: 21 Aug 2024 15:30 Let's hope it's a case of plugging the new ICs in and then off you go. What were the faulty ones? I seem to go through 74157s and 257s at the mo

So far it's been: 74LS273, 74LS00, 74LS10, 74LS20, 74LS04, 74LS32 and 74LS139.

Given that there are only 14 LS IC's it's not a good look...

Well the last of my replacement IC's arrived today and the result is a fully working Plus 1 :)

*HELP reveals all the ROM extensions and it works great with my ELKSD Plus1:


The Joystick port works just fine.

Looks great retrobrited too :)


And here are the culprits:


Out of 14 74LS ICs on the board, 7 are dead or partially dead. Seems like going swimming is not a good thing for a Plus 1 to do.

Happy to have it fixed and working :)

:cheer: :cheer: :cheer:

Yay! TTL carnage.

stephen_usher wrote: 24 Aug 2024 12:31 Yay! TTL carnage.

I'd go with apocalypse, but carnage works too...

One final thing. I upgraded the Plus 1 ROM from here: Plus 1 Enhanced ROM

Was a bit of a fiddle, I was told I should burn 4 copies across a 27C256, however I didn't twig that the ROM did not end on a boundary so I ended up with 3 copies slightly off from where they should have been.

Once I realised and erased the EPROM, I built a new image with each copy padded so that they would start at the correct location, and it works just fine now:


I'll keep the original safe just in case, though I have backed it up regardless.

I've attached the ROM image in case anybody else needs it.