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Identify old 5.25 FDD

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First post, by Remonter

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Hello everyone!
I have old 5.25 FDD without markings. Manufactured in 1990. This FDD looks ok, but not working. I think this drive is DS/DD, because i have only HD diskettes and they not works with this drive. Or heads just need to be adjusted. At first i want to know what i have). The board very similar on Qumetrak 142 with shape and component placement.

IMG_20210506_184224.jpg
IMG_20210506_184239.jpg
frontpanel.jpg
backside.jpg
Last edited by Remonter on 2021-05-16, 15:19. Edited 1 time in total.

Reply 1 of 7, by Miphee

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Interesting burned mess at the power connector. Looks like a handmade conversion to replace a different (perhaps proprietary) connector.

Reply 2 of 7, by Remonter

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I dont think so. It looks like have been repaired with connector what they have)

Reply 3 of 7, by Am386DX-40

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Upload a picture that shows it from behind

Reply 4 of 7, by snufkin

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Can't help with IDing the drive, but what are you using the drive with? It looks like the jumper is set to DS0, when I think the standard for PCs is DS1?

Reply 5 of 7, by Remonter

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Am386DX-40 wrote on 2021-05-14, 20:29:

Upload a picture that shows it from behind

Done. Added photo to the first post

Reply 6 of 7, by Remonter

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I`ve checked disk rotation speed with oscilloscope. Drive has 300 rpm. Then i I have used Teledisk from Daves Old Computers site to test drive. Drive has 40 tracks. So, i know its DS DD drive. I saw some data on last tracks at 250 kbps. Now i am trying to find good DD 360 diskette to make head alignment with it.
What mean "RMS" jumper? When i removing this jumper heads move to center of disk.

Reply 7 of 7, by snufkin

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Remonter wrote on 2021-05-18, 12:00:

What mean "RMS" jumper? When i removing this jumper heads move to center of disk.

I'd hazard a guess that it's the supply to the RM1 resistor pack, probably selects if the termination resistors are connected or not. So only fitted on the last drive in a chain. Bus signal levels might do odd things without it (like stepping the head to the middle). Maybe. I'm guessing most on the RMS->RM1 names being similar and the location. I think normally jumpers labelled MS would be to do with whether the motor started on the drive select or motor run signals.