That is one gigantic floppy drive!!

Topics related to older 6502-based hardware and systems including (but not limited to) the MOS Technology KIM-1, Synertek SYM-1, and Rockwell AIM-65.
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Dr Jefyll
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Re: That is one gigantic floppy drive!!

Post by Dr Jefyll »

Tor wrote:
The guy I got my drive(s) from told me that in the end only an original Shugart power supply would do - he had tried various other options without success.
It sounds to me as if he should have tried harder, or sought advice from a person more competent than himself. It's hard to believe an original Shugart power supply is the only solution.
tingo wrote:
Some 8-inch floppy drives use a 24 V DC motor; PSU'e for that are easy to find.
Right. And some of those 8 inch drives have motors that run straight off 115VAC mains power, and thus require no power supply.

-- Jeff
In 1988 my 65C02 got six new registers and 44 new full-speed instructions!
https://laughtonelectronics.com/Arcana/ ... mmary.html
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BigEd
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Re: That is one gigantic floppy drive!!

Post by BigEd »

Hey, some of us live in the land of 240V! (230 volts -6%, +10%)
Tor
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Re: That is one gigantic floppy drive!!

Post by Tor »

Jeff,

Certainly it would be possible to find a PSU that did the job - I don't think the guy meant it literally when he said that "only" the Shugart PSU did the job. It's just that it worked, no issues. I believe the problem with the (24V) PSUs he tried was that although they were spec'ed to provide enough current, they couldn't handle the initial surge. Of course it's possible to find 3party PSUs that can do that, just as I managed to find a 5V PSU which can provide 200A.
It's just that the general PSUs he tried weren't up to it.
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cbmeeks
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Re: That is one gigantic floppy drive!!

Post by cbmeeks »

tingo wrote:
OP: you could always try to get OUP-M (https://github.com/option8/OUP-M) running on your 6502 with that 8-inch drive.
Some 8-inch floppy drives use a 24 V DC motor; PSU'e for that are easy to find.
That looks interesting. I will check that out! Thanks.
Tor wrote:
Do you have a power supply for yours? Because these things need a beefy supply. The guy I got my drive(s) from told me that in the end only an original Shugart power supply would do - he had tried various other options without success.
No, not at the moment. I haven't researched the PSU requirements but I'm assuming a modern ATX PSU could be retrofitted to it. Unless it needs some odd voltages. Or maybe even -5V which I think most modern PSU's don't contain anymore. I'm sure something could be found/made.
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Dr Jefyll
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Re: That is one gigantic floppy drive!!

Post by Dr Jefyll »

Tor wrote:
Jeff,

Certainly it would be possible to find a PSU that did the job - I don't think the guy meant it literally when he said that "only" the Shugart PSU did the job. It's just that it worked, no issues. I believe the problem with the (24V) PSUs he tried was that although they were spec'ed to provide enough current, they couldn't handle the initial surge. Of course it's possible to find 3party PSUs that can do that, just as I managed to find a 5V PSU which can provide 200A.
It's just that the general PSUs he tried weren't up to it.
Hi, Tor. I didn't mean to sound critical, and I apologize. But it seems clear that something is wrong somewhere if the PSU's were spec'ed to provide enough current but couldn't handle the initial surge. Surely the spec (for the drive, I mean) would -- or ought to -- indicate maximum current demand (including the initial surge). So, maybe there's a documentation problem regarding the drive.

-- Jeff
In 1988 my 65C02 got six new registers and 44 new full-speed instructions!
https://laughtonelectronics.com/Arcana/ ... mmary.html
Tor
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Re: That is one gigantic floppy drive!!

Post by Tor »

Yeah, the thing is - according to the specs (I have the OEM manual), the requirements are modest. And the maximum current *is* specified. That was what frustrated the guy that gave me the drive - he tried various PSUs that *should* be OK and it just didn't work. And he should know what he was doing - he used those drives when he worked at a minicomputer manufacturer, as a tech.
The only possibility I can see is that the 'maximum current' figure in the docs isn't anywhere near the actual initial surge (or some other transient surge).
whartung
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Re: That is one gigantic floppy drive!!

Post by whartung »

Could be a short or some mechanical jamming that's putting extra load on the system with the motor being stuck.
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