Hello.
I am experiencing issue with my Atari 520 STF (520 ko). While playing a game the screen suddenly froze. And no way to boot again. In place I have a light blue screen.
I immediately thought of a memory issue. But after checking continuity with great care, i can not find any short. I also change all the ships for new ones but nothing changed. All the ships are powered with 5v.
My Atari does not boot...
The photo below shows the screen I have when starting the machine with the Exxos test cartridge.
Would you have any idea ?
Unless it's a video problem?
Thank you for your help.
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520 STF - Blue screen - Ram issue ?
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doc
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520 STF - Blue screen - Ram issue ?
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stephen_usher
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Re: 520 STF - Blue screen - Ram issue ?
The first thing I would try is to reseat the Shifter chip.
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.
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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kodak80
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Re: 520 STF - Blue screen - Ram issue ?
I fixed a board (STFM 512kb) on the weekend with a similar screen output, blue blocks with a white boarder and it was due to a faulty LS244 chip. I love that my TL866II programmer can test Logic chips. RAM chips turned out to be fine. Once the board booted, I also found a faulty LS373 chip and faulty DMA chip, neither of these last 2 faulty chips stopped the board booting.
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rubber_jonnie
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Re: 520 STF - Blue screen - Ram issue ?
I'd clean the MMU and Glue IC pins and sockets as well as the Shifter.
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...
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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doc
- Posts: 39
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Re: 520 STF - Blue screen - Ram issue ?
Thank you for theses clues
So I changed the shifter with one functioning on another 520 ST -> Nothing changed
I removed the 2 LS373 without replacing them -> Nothing changed
I changed the 2 LS373 with 2 LS274 (in case I only had that) -> Nothing changed
I piggy plugged a LS244 on one ship -> Nothing changed
I piggy plugged a LS244 on the second chip -> Something changed !!!! Same mess with many colors ;)
Look at the pictures
And after a reset
Any more ideas ? Do you think I should unsolder the suspected LS244 to firmly replace it ?
I own a TL866II PLUS but I cannot find how to test SN74LS chips... How do you proceed ?
So I changed the shifter with one functioning on another 520 ST -> Nothing changed
I removed the 2 LS373 without replacing them -> Nothing changed
I changed the 2 LS373 with 2 LS274 (in case I only had that) -> Nothing changed
I piggy plugged a LS244 on one ship -> Nothing changed
I piggy plugged a LS244 on the second chip -> Something changed !!!! Same mess with many colors ;)
Look at the pictures
And after a reset
Any more ideas ? Do you think I should unsolder the suspected LS244 to firmly replace it ?
I own a TL866II PLUS but I cannot find how to test SN74LS chips... How do you proceed ?
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DoG
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Re: 520 STF - Blue screen - Ram issue ?
In menu -> [Device] -> [Logic IC test] -> Choose [74244]doc wrote: 14 Apr 2022 17:49 ...I own a TL866II PLUS but I cannot find how to test SN74LS chips... How do you proceed ?...
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Steve
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Re: 520 STF - Blue screen - Ram issue ?
You should always reseat and clean all removable chips before resorting to soldering or replacing chips. You could cause a problem on top of your original problem.
Have you cleaned and reseated every chip yet?
Have you cleaned and reseated every chip yet?
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