White Screen After Exxos PSU Install

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Acill
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White Screen After Exxos PSU Install

Post by Acill »

I wired up my new Exxos PSU in 110 mode this evening and thought I did something wrong at first. After powering it up and checking the output voltages all was spot on. Nice 5V and 12V. Connecting it to the motherboard and powering up I just get a white screen on my STE with 1MB. On a hunch I hit the reset button and it comes up and boots fine. For whatever reason it just hangs on the white screen if I power it off and then on again. It will only start up once I hit the rest.

Ideas?
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stephen_usher
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Re: White Screen After Exxos PSU Install

Post by stephen_usher »

The capacitor in the reset circuit.

The old power supply would have had a slightly different Vcc voltage which would fill the capacitor at a slightly different rate.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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rubber_jonnie
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Re: White Screen After Exxos PSU Install

Post by rubber_jonnie »

Agree with @stephen_usher .

More info can be found here: https://www.exxosforum.co.uk/forum/viewt ... =17&t=2175
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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exxos
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Re: White Screen After Exxos PSU Install

Post by exxos »

Yes reset circuit has gone bad. It's listed in the PSU install FAQ and in the mandatory fixes pages.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Acill
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Joined: Sat Sep 12, 2020 7:35 pm

Re: White Screen After Exxos PSU Install

Post by Acill »

Thanks everyone! After reading that linked reset circuit post I see its exactly what is happening. I have done a recap on this board, but replacing C100 with a 47uF seems to have fixed this issue. It was a 10uF as that was what I saw there before. Thats quite a difference!

Looking over the other fixes I see listed, I may just order and do them all now. Other than this reset though things seem pretty great with the machine. The old PSU was working fine, and the crazy thing is it was from the UK but still operated fine here on 110V without issues, but was looking pretty bad and probably on its way out.
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exxos
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Re: White Screen After Exxos PSU Install

Post by exxos »

Glad you're sorted :thumbup:

Might be worth checking if your original PSU had a spec sticker on it. IIRC some versions of the PSU were actually dual voltage.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
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rubber_jonnie
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Re: White Screen After Exxos PSU Install

Post by rubber_jonnie »

Splendid.

:girldance: :girldance: :girldance:
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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stephen_usher
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Re: White Screen After Exxos PSU Install

Post by stephen_usher »

Excellent.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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