Floppy Drive read problems

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PhilC
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Floppy Drive read problems

Post by PhilC »

Evening All.

I had a bit of time today working with one if my non functional Mega STs.

With a floppy connected and disk in the drive it would come up with 2 bombs. Did the same with a gotek fitted as well.

Today I socketed the MFP and YM and replaced them with new.

So now the Mega with a disk in will boot to desktop but shows all disks as empty. I have tried formatting a new disk and it goes through the format process and fails at the end.

I'm going to socket the DMA and Shifter as well as I intend to keep this Mega as it's in a pretty good condition otherwise.

Other things I've changed, WD1772, upgraded to 4mb, recapped psu, swapped GLUE for known working.

Just wondering where you all think I should look next?
If it ain't broke, test it to Destruction.
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exxos
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Re: Floppy Drive read problems

Post by exxos »

Pull ups on the DMA data bus and 1772 buffer outputs... Both fixes done on the remake and documented in the tweaks and fixes section.
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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Re: Floppy Drive read problems

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exxos wrote: Sat Jan 19, 2019 7:56 pm Pull ups on the DMA data bus and 1772 buffer outputs... Both fixes done on the remake and documented in the tweaks and fixes section.
Cool, will try that tomorrow
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Re: Floppy Drive read problems

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well, surprisingly that fixed my other Mega, not the one I as expecting, LOL, as I did the patch to both.

The unfixed one still shows blank drives and doesn't boot to the UltraSatan but as I said, no the UltraSatan works great on the other Mega.

So one fixed fine, another to ork out hats going wrong. Will get everything else socketed and see how we go next.
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Re: Floppy Drive read problems

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Did you do both fixes?
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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Re: Floppy Drive read problems

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exxos wrote: Sun Jan 20, 2019 6:16 pm Did you do both fixes?
Yes I did both of them
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Re: Floppy Drive read problems

Post by exxos »

Also bare in mind IMP DMAs need a diode in series with the 5v if your swapping those about. IMP are pretty evil.
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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Re: Floppy Drive read problems

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exxos wrote: Sun Jan 20, 2019 6:44 pm Also bare in mind IMP DMAs need a diode in series with the 5v if your swapping those about. IMP are pretty evil.
Fortunately no IMP on this board and the spare DMAs I have too are mostly not IMP. Got to be something daft as everything else works fine.
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Re: Floppy Drive read problems

Post by PhilC »

And yes, It was the DMA. Socketed it and swapped it for another and we are back in business with the Floppy and Ultrasatan :cheer: :cheer:
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Re: Floppy Drive read problems

Post by exxos »

Forgottenmyname wrote: Tue Jan 29, 2019 9:49 pm And yes, It was the DMA. Socketed it and swapped it for another and we are back in business with the Floppy and Ultrasatan :cheer: :cheer:
:bravo:

You little DMA killer you...
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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