Icky made me do it - TRS-80 CoCo

[rubber_jonnie]

Well wow. I ordered the 14529 yesterday and it's just arrived through the door!!! Very impressed with the speed of delivery indeed.

And, for all of you waiting to hear the result, it's now fixed :) Makes me wonder, that IC was already socketed, so did they know from the off that it was unreliable? Was the socket for an easy no sound fix? Or had it already been reworked for a dead one prior? Given the warranty seal from the factory was unbroken, I'd suspect it was that way from the off, just in case.

Probably never know, but will be the first place I look if the sound fails again.

I hadn't even begun to look at the RAM upgrade stuff!!!

[stephen_usher]

Yay!

[rubber_jonnie]

Yay!

Yay! indeed. I never expected the IC to arrive the day after I ordered it :)

I also hooked the 'scope to TP 14 and the output pin of the cassette port, as I can't hear the cassette sound over audio anymore. It works just fine, I see the signal at both points :)

[rubber_jonnie]

OK, so it turns out Tandy were quite smart with the variant of Coco 1 that I have.

The RAM upgrade just requires 4 jumpers to be changed, 8 RAM chips (416's basically the same as a 4116) to be swapped, and the removal of 8 capacitors (C70 to C77).

First off, the jumpers change the socket behaviour and remove the -5v from pin 1, the 12v from pin 8 and move 5v from pin 9 to pin 8.

The caps are on what was pin 9, which used to be +5v, however it is now A7, meaning A7 is connected to GND via the caps, so the caps have to go leaving A7 unfettered.

Then it's just a case of dropping in 8 new 4164 RAM ICs and Robert is your relative, 64KB, of which about 31 KB is free for BASIC.

Next up I need to get the CocoSDC working. Not that it doesn't, it works with the Dragon 32 just fine, just doesn't work with the Coco.

For now.

[rubber_jonnie]

Have to say, the combination of the TRS-80 Coco and the Plustron 5" B&W TV really does give off a Fallout vibe:

IMG20240229093246.jpg

[stephen_usher]

:lol:

You need some Nuka Cola bottle caps and bottles.

[rubber_jonnie]

:lol:

You need some Nuka Cola bottle caps and bottles.

I do!!!

[rubber_jonnie]

My TSR-80 cart arrived this morning, the contacts are best described as awful:

IMG20240229105330.jpg

IMG20240229105318.jpg

Looking much better after a clean with a fibreglass pencil, IPA and contact cleaner.

[PhilC]

I’m f you’ve got the PC version of fallout 3 or 4, I think the 3D models are easily accessible, should help with getting the labels made :lol:

[rubber_jonnie]

I’m f you’ve got the PC version of fallout 3 or 4, I think the 3D models are easily accessible, should help with getting the labels made :lol:

LOL

Maybe I should make a PIP Boy as well :)