The Naked Atari 800

[rubber_jonnie]

Thanks @rubber_jonnie. I have a big crack in the top case of the 800, so I take the case off as little as possible.

I should probably get round to stabilising the crack when I fit the Pokeymax.

Sounds like a plan, but unfortunately to fit your PokeyMax you're going to have to pull the case off, so definitely a good time to work on that crack.

[rubber_jonnie]

OK a little more clock shenanigans tonight.

I lifted pin 16 of the GTIA which is where the colourburst clock comes into it. No colourburst clock and everything is monochrome, all good.

I then gave the clock module an ATTiny that had the PAL master clock and PAL colourburst clock programmed on clocks 0 and 1 of the Si5351 board and hooked clock 1 up pin 16 of the GTIA.

Well it all worked a treat so the clock module is now doing double duty as the master clock at 3.546894 Mhz and the colourburst clock at 4.433618 Mhz You can see all the hook up points here:

IMG20260129190608.jpg (285.77 KiB) Viewed 720 times

GTIA hookup on pin 16 is here, the other end of the green cliplead:

IMG20260129190756.jpg (245.16 KiB) Viewed 720 times

Colour looks great:

IMG20260129190621.jpg (194.98 KiB) Viewed 720 times

Clocks measure just right:

IMG20260129190614.jpg (237.99 KiB) Viewed 720 times

And the whole ensemble looks spot on

.

IMG20260129190632.jpg (394.84 KiB) Viewed 720 times

It's all standalone and powered direct from the Atari 800.

I have to say this project has worked out far better than I could ever have hoped for. As a test I'm going to see if this setup will work in one of my 2600's doing the job of the same crystals.

I'm fairly sure it would work in most scenarios where you can't find a crystal.

[stephen_usher]

[rubber_jonnie]

Well, the Naked Atari 800 is no longer Naked!!!


It's wearing underwear

IMG20260130140547.jpg (380.13 KiB) Viewed 701 times

Currently just running the master clock with the Si5351 but I have a plan to add the colourburst clock now that I know where it's supposed to connect to on the CPU board.

I should be able to simply lift a single resistor on the CPU board to disconnect the on board colourburst clock and then solder in a wire to the trace that connects to pin 16 of the GTIA and take both clocks from the Si5351.

[rubber_jonnie]

I've got a Pokeymax that I was thinking of putting in to my 800 but haven't looked how hard it is or where the pokey actually is.

I just got this:

IMG20260201173709.jpg (221.24 KiB) Viewed 675 times

I was struggling to get another PokeyMax so I thought I'd give AcidStereo a try. It will likely be going into my own 800.

[PhilC]

@rubber_jonnie I shall be watching, ready for fitting mine then.

[rubber_jonnie]

@rubber_jonnie I shall be watching, ready for fitting mine then.

It looks to all intents and purposes very like the PokeyMax, soo I suspect it will be a similar experience. Not sure if my good 800 (Not the one on this thread) has a socketed Pokey, I can't recall.

Either way I think it'll work out just fine. I'll run a separate thread on it when I get round to it.

[ijor]

It looks to all intents and purposes very like the PokeyMax

I don't have any personal experience with that board, but seems it is not exactly the same. This one requires the original Pokey to be installed. That's why it has a pass through socket. Pokeymax, does not.

[rubber_jonnie]

It looks to all intents and purposes very like the PokeyMax

I don't have any personal experience with that board, but seems it is not exactly the same. This one requires the original Pokey to be installed. That's why it has a pass through socket. Pokeymax, does not.

True but does retain the original Pokey just for SIO and keyboard functions and does include 2 Pokey/4 Covox in the FPGA, so the end result is really quite similar to PokeyMax, just done in a slightly different manner.

Unfortunately I've struggled to find PokeyMax of late (I already have 2, one in an XL the other in an XE) and prices have gone up, so I'll happily try the alternative that is available. It's frustrating as PokeyMax is a known quantity to me, but what can you do?

[ijor]

Unfortunately I've struggled to find PokeyMax of late (I already have 2, one in an XL the other in an XE) and prices have gone up, so I'll happily try the alternative that is available. It's frustrating as PokeyMax is a known quantity to me, but what can you do?

Mark (PokeyMax developer) is just going to release the first batch of PokeyMax's last version. I understand he already ordered the boards from the manufacturer, but he might still have a few unsold ones, if you are interested:

https://forums.atariage.com/topic/38658 ... er-thread/