Atari Mega ST 2 White Screen

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mattsoft
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Atari Mega ST 2 White Screen

Post by mattsoft » Thu Jul 11, 2019 6:52 am

Hi all -

Tonight we were playing some games on my Mega ST 2 and I noticed some horizontal lines on the screen. At first I though it was the monitor, but then I hit the reset button and the ST never came back. Instead, I just get a white screen -- no floppy access. The keyboard LED does light up though. I have not started troubleshooting yet, but plan to open her up soon and first check voltages on the PSU, then make sure all socketed chips are well-seated. After that, is there anything obvious? I don't have spare chips (GLUE, Shifter, etc...) to start chip swapping, but I'm hoping there is maybe something I could check with a logic probe.

Thanks!
-matt

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exxos
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Re: Atari Mega ST 2 White Screen

Post by exxos » Thu Jul 11, 2019 8:00 am

Could be the reset switch has broke if it was working before you pressed it ?
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

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mattsoft
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Re: Atari Mega ST 2 White Screen

Post by mattsoft » Thu Jul 11, 2019 4:47 pm

exxos wrote:
Thu Jul 11, 2019 8:00 am
Could be the reset switch has broke if it was working before you pressed it ?
Yeah, that could be possible. When I press the reset button, nothing seemingly happens.

UPDATE: this morning, approx. 12 hours after last use, I powered on and everything works fine now.

:shock:

Maybe having the ST run for 3 hours straight it was overheating? I still need to open it up and check for loose chips. Maybe something is expanding with heat and not seated properly.

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exxos
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Re: Atari Mega ST 2 White Screen

Post by exxos » Thu Jul 11, 2019 4:53 pm

If the PSU hasn't been recapped then that could be a issue.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

mattsoft
Posts: 4
Joined: Thu Jul 11, 2019 6:48 am

Re: Atari Mega ST 2 White Screen

Post by mattsoft » Fri Jul 12, 2019 4:19 pm

exxos wrote:
Thu Jul 11, 2019 4:53 pm
If the PSU hasn't been recapped then that could be a issue.
It has not been recapped. I'll let it run some more and see if I can reproduce. If it acts up again, I'll measure PSU voltage and go from there. Thanks!

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