Acorn Atom Replica build

[rubber_jonnie]

And the volume problem is solved :)

IMG20260320103515.jpg

I bought some small amps ages ago when I was adding sound to my TRS80-Model 1 and I have spares, so this one went into the Atom and volume is just fine and can even be turned off if required.

I will be doing a similar mod to one of my BBC model B's soon so I have volume and muting control there too.

[PhilC]

@rubber_jonnie you shouldn't need to do that with the Beeb. There is a pot that does volume control already. So you could just change that to a more friendly variety?

[rubber_jonnie]

@rubber_jonnie you shouldn't need to do that with the Beeb. There is a pot that does volume control already. So you could just change that to a more friendly variety?

Yeah, I may just add an external pot, it will be a bit easier for sure.

[rubber_jonnie]

Well, I have placed an order for Yarrb-M2 and AtoMMCv4 with @roland over at Stardot, so looking forward to those arriving and getting them tested.

It's fantastic what can be done for these old machines today :)

[HigashiJun]

It's fantastic what can be done for these old machines today :)

For sure !

[rubber_jonnie]

Good news, according to the tracking the Yarrb-M2 & AtoMMCv4 are in the post and expected Tuesday.

Of course the post being the post, I'll take it with a pinch of salt, but at least they're on the way :)

[rubber_jonnie]

Well, Yarrb M2 and AtoMMC v4 arrived today:

IMG20260331142257.jpg

But a busy day meant I've only just got them installed and working. Here is Yarrb M2 installed:

IMG20260331211723.jpg

And it requires the removal of all the RAM to the left of the CPU plus IC's 5 and 6 and a bit of logic in IC44 is modded, and a couple of bodge wires added:

IMG20260331211747.jpg

Yarrb has a 'Test' ROM built in selected by a jumper and that ran perfectly:

IMG20260331211659.jpg

And the AtoMMC V4 plugs in to a header on top just behind the keyboard:

IMG20260331212303.jpg

And the machine sees the ROM for it and tries to run *MENU on boot:

IMG20260331213637.jpg

However I haven't got an SD card sorted for it yet, hence why it errors.

It's odd, but the keyboard doesn't work with the AtoMMC removed, but thats fine since it works with it plugged in. I thought I'd killed another 8255, but thankfully just the keyboard not working without AtoMMC.

[rubber_jonnie]

And now with an SD card things are looking good!!!

IMG20260401102945.jpg

IMG20260401102952.jpg

One question @PhilC I thought it was supposed to be green, but I just get B&W, also it says NTSC on my display when the Atom powers up. Crystals are correct and as per the BoM...

[HigashiJun]

Nice progress !

[rubber_jonnie]

Nice progress !

Thanks :)