exxos's Atari, Amiga & retro forum

I'm Geordi,

My first computer was an IBM PC-Compatible 386, I'm really fond of my Commodores, but my XEGS is probably of more interest to you.

I bought a Commodore 64 in high school (late 90s), and I've been collecting vintage ever since. My C64 died with its power supply, and that led me to purchase a VIC20 (for the power supply). I repaired the 64 by simply socketing the ram and replacing a damaged memory IC, and that inspired me to continue fixing old computers. I picked up a broken 386 tower at a garage sale for $1 and repaired its old Texas Instruments BIOS with built-in battery.

After the Commodore 64, I bought a Commodore CDTV - It wasn't even vintage at the time, being only 10 years old, but the architecture it is based on goes back the 1985. I really love my CDTV and I'm resistant to modding it (it's still stock). I got lucky and found an A500 with 1084S locally, and I've been upgrading that slowly. Along the way, I've acquired quite a few accessories and have had to make repairs to a short list of things since.

A few years back, I traded a red-ring-of-death Xbox360 for a complete XEGS set (Keyboard, light gun, power supply, bughunt). The XEGS is dead (no video), but I've finally built the confidence to attempt a repair. I've got the sockets, memory, and a FREDDIE replacement. I think I'm ready to repair it. Hopefully, simply replacing the memory & FREDDIE will take care of it. If not, I've got you guys, right?

And I know I've already mentioned my CDTV, but it's really awesome and its time has finally come. Captain Future has successfully patched the CDTV OS - I'm very excited about this. https://cdtvland.com/2021/12/20/free-cd ... e-out-now/

Take care!

:welcomewave:

Welcome to the forum!

:swave:

:welcomewave:

Does the XEGS boot into ram test mode? Most of the issues with the 8 bit Ataris are related to bad ram.

:welcomewave:

Good luck with the XEGS, I had a dead one about 25 years ago and regret getting rid of it, as these days I'd probably be able to fix it.

I suspect you may be right with the RAM and or Freddie diagnosis, just be careful desoldering as the boards are really fragile.

PhilC wrote: 22 Dec 2021 08:34 :welcomewave:

Does the XEGS boot into ram test mode? Most of the issues with the 8 bit Ataris are related to bad ram.

No video whatsoever, unfortunately. Ram is definitely suspect, but the lack of video (according to some googling I did) indicates either the FREDDIE, the MMU, or the 6502 - with the FREDDIE being the most likely culprit. I've tested the power supply, and it seems fine. But, I went ahead and ordered a USB->Atari.power.din cable so I can use a modern power supply.

The FREDDIE replacement is not an original FREDDIE (I couldn't find those), it's a tiny PCB from Poland with a bunch of tiny ICs on it. I got it from an eBay seller connected to www.galtron.pl. Has anyone here used this replacement board before?

rubber_jonnie wrote: 22 Dec 2021 09:21 [...] just be careful desoldering as the boards are really fragile.

Thank you.

Is Atari solder as intractable as Commodore's? I use a heat gun to warm stubborn PCBs, usually only to around 115C peak. That's not too warm for this board is it?

Geordi wrote: 22 Dec 2021 14:36

rubber_jonnie wrote: 22 Dec 2021 09:21 [...] just be careful desoldering as the boards are really fragile.

Thank you.

Is Atari solder as intractable as Commodore's? I use a heat gun to warm stubborn PCBs, usually only to around 115C peak. That's not too warm for this board is it?

Honestly I rarely use a heat gun on any of my Ataris as I have a proper desolder gun, so I'm not the best person to advise, though the work I've done on my 800XL and 65XE have shown me no real problems with solder.

If you are going to do so, then you really need to monitor the board very closely to make sure it isn't getting too hot and burning.

rubber_jonnie wrote: 22 Dec 2021 14:45 Honestly I rarely use a heat gun on any of my Ataris as I have a proper desolder gun, so I'm not the best person to advise, though the work I've done on my 800XL and 65XE have shown me no real problems with solder.

If you are going to do so, then you really need to monitor the board very closely to make sure it isn't getting too hot and burning.

Okay!

I only use the heat gun on really difficult boards. And then, I use an infrared monitor and turn the heat off as soon as the component gets up to temp (then use the soldering iron the rest of the way).

Thank you.

Geordi wrote: 22 Dec 2021 14:50

rubber_jonnie wrote: 22 Dec 2021 14:45 Honestly I rarely use a heat gun on any of my Ataris as I have a proper desolder gun, so I'm not the best person to advise, though the work I've done on my 800XL and 65XE have shown me no real problems with solder.

If you are going to do so, then you really need to monitor the board very closely to make sure it isn't getting too hot and burning.

Okay!

I only use the heat gun on really difficult boards. And then, I use an infrared monitor and turn the heat off as soon as the component gets up to temp (then use the soldering iron the rest of the way).

Thank you.

Sounds like you're on the right track there :)

One quick Q, have you checked power is good? The old Atari PSUs from that era are not great. I'm sure you probably have but always worth asking.

If you have a decent bench PSU it may be worth using that for consistency when you're troubleshooting.

Oh, and one other thing! Make sure you document all your work here :)

Good luck!!