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vintage computers, tubes, the MOnSter6502, cross-sectioned electronic parts. coauthor of https://t.co/lquWXu6v7m. ⚠ please read https://t.co/PrGDtiV6c5

Jan 18, 2022, 15 tweets

finally got one of these cool MFM hard drive emulator boards! it can pretend to be a hard drive or it can analyze one.

plugged into one of my ST-412 drives.

it works!

maybe I should use it to analyze the drive in this HP9133. yeah there's a hard drive inside it.

the drive uses HPIB to connect to the host computer, so it has a controller board built in.

told ya there's a hard drive inside. it even has a bezel.

it's an ST-419.

looks familiar. very much like the ST-412.

interesting, it detects the controller format.

archived! the drive is also running a lot quieter. i'm running it upside down like @WysWyg_Protogen suggested for my ST-412s. once the lubrication warms up, it can flow back down into the bearings.

more info on the MFM emulator: pdp8online.com/mfm/

the HP 9133 uses a weird early Sony floppy drive. they tend to get gummed up so I'll need to take it apart to check the grease. if you don't do this, the disk won't eject, and if you yank on it, it'll tear out the upper read/write head.

sure enough it was a bit sticky. I added some grease and freed it up.

well, the controller isn't happy. I think there were some bad sectors at the beginning of the drive, so that's probably why

the diagnostic test jumper was on. it's set to a floppy drive test, and there's no disk in the drive, which is probably why it failed.

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