exxos's Atari, Amiga & retro forum

Hi Folks! I'm having some troubles with my 1040STe.

I picked this machine up a couple years ago from the UK. I replaced the PSU with a 110v psu so I wouldn't have to use a step up transformer to power it.

Problem is this: Once first powered on everything generally works fine. After about 15 to 25 minutes I start getting lock ups. The unit will just freeze or I will typically get 3 bombs. If I power it off for quite a while it will continue to work again.

So far I have tried 2 different PSUs in it. Including a Picopsu mod. Both exhibit the same behavior. So I don't think it's PSU related.

The machine has 4 megabytes ram and only mod to it has been that I replaced the floppy drive with a Gotek floppy emulator. Running the latest HxC firmware. No external HD or other mass media. I use a PS/2 to Atari mouse interface so that I can use a regular PS/2 mouse. TOS 1.62

I have pulled and reseated several IC's on the board, though I haven't done them all yet. It appears to me that something is overheating, however with the occasional 3 bombs I am not sure.

I have also ran the machine without the top of the case on it and the lockups still occur.

Could this be signs of a bad cpu? Perhaps some other component is heating up and causing the fault?

I have owned several STe machines over the years and haven't seen this kind of behavior before.


Thanks!

You need to recap your PSU.. pico's a lot of them are worse than a failing Atari PSU.

exxos wrote: 14 May 2018 10:20 You need to recap your PSU.. pico's a lot of them are worse than a failing Atari PSU.

Definitely do the above first. Or try a different genuine Atari PSU if you have one available. As exxos says, Picos are not ideal.

Also, have you tried a different set of SIMMS? or Cleaned the contacts on the SIMMS with IPA?

By removing the top of the case, do you mean plastic case or steel shroud? or both? Airflow in ST/STF/STFM & STEs relies on the hot air rising, and this causes a flow through the system, but it's not great, so any component that is overheating is likely to suffer with the casework on.

rubber_jonnie wrote: 14 May 2018 11:30

exxos wrote: 14 May 2018 10:20 You need to recap your PSU.. pico's a lot of them are worse than a failing Atari PSU.

Definitely do the above first. Or try a different genuine Atari PSU if you have one available. As exxos says, Picos are not ideal.

Also, have you tried a different set of SIMMS? or Cleaned the contacts on the SIMMS with IPA?

By removing the top of the case, do you mean plastic case or steel shroud? or both? Airflow in ST/STF/STFM & STEs relies on the hot air rising, and this causes a flow through the system, but it's not great, so any component that is overheating is likely to suffer with the casework on.

Actually my Atari psu has been recapped. I forgot to mention that.

And by top off, I do mean both the plastic and the metal RF shield both off.

Did you recap with one of my kits or some other brands of caps ? Checked for bad joints all over the board ? new switch ?

I would run this program and leave it on for a few hours and see what happens..https://www.exxosforum.co.uk/forum/viewt ... ?f=25&t=28

I'd try hunting for an unusually hot IC, wrong resistance on a bus (adress or data) ... the alternative might be hairline cracks somewhere ...

(I have a MegaSTE where it seems the DMA bus goes wonky after 10-15 minutes .. so maybe something similar. There I'm thinking of adding resistance to the pullups)

/Troed

Took the plastic case top off my STe, removed the RF shield and left the keyboard outside the case for maximum ventilation.
Airconditioning was running and the ambient room temp was about 74f/23c.

Ran a few demos and didn't see any crashing.



Ran YAART overnight. Completed 48 passes with zero errors before the machine bombed out with 11 bombs.

I would suggest trying the HC type CPU and see if that helps..

As troed said also, you may need to change the SIL resistors.. what values are on the address and databus on your machine ? (they are located around the CPU & blitter ). All the red ones like on this image.. https://www.exxosforum.co.uk/forum/viewt ... =783#p5568

exxos wrote: 15 May 2018 16:15 I would suggest trying the HC type CPU and see if that helps..

As troed said also, you may need to change the SIL resistors.. what values are on the address and databus on your machine ? (they are located around the CPU & blitter ). All the red ones like on this image.. https://www.exxosforum.co.uk/forum/viewt ... =783#p5568

I will look into this info and report back.

Couple pics of the area around the cpu and blitter.