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Tandon TM-100 2A maximum track question

clh333

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I have several Tandon TM-100 2A (360k, DSDD) drives I have acquired as part of systems or from eBay. After cleaning the castings, heads and rails I usually hook them up to a SuperCard Pro and check rotational speed and variance and step them out to maximum track. Most times they report they can step to track 43 or so.

Two I have tested recently reported (via the SCP software dialog) that they stepped out to track 44 and then the count immediately jumped to 80, briefly. The maximum track reported by the SCP was 79 in both cases.

I did some research on these drives and found an article that suggested the clamp on the stepper motor spindle might be loose, but after tightening the same problem exhibited. Has anyone seen this occur or have an idea why it may be happening? I posted this on the CBMSTUFF forum; they don't think the problem was with the SCP.

If I never attempt to go beyond track 39 or 40 would it be likely to make a difference? In other words, can I ignore this?

Thanks for your replies.

-CH-
 

Chuck(G)

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Much beyond 42 and you're in dangerous territory. Note that some drives will jam the carriage and require you to manually free the carriage. As there's no detection mechanism for the maximum track, you're on your own as to where the head really is.
 

SomeGuy

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What I would suggest is to do a simple alignment test. Just use any good quality factory-original floppy disk (like a mouse or video driver disk) and see if it reads and decodes %100. If it can reliably read the disk, then there probably isn't any problem. Although you might want to repeat that test ocasionally.

Also, just a double-check, you are sure these are the 360k TM100-2A (48tpi) model? They should be labeled on the bottom. Tandon did also make a similar looking 96TPI track and 100TPI drive.

Are you just testing these drives to see if they work? For software archival, I would not recommend a belt-driven drive.
 

Chuck(G)

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Also, just a double-check, you are sure these are the 360k TM100-2A (48tpi) model? They should be labeled on the bottom. Tandon did also make a similar looking 96TPI track and 100TPI drive.

96 tpi = TM100-4
100 tpi = TM100-4M

Note also, that the pinout for the 4M is "Micropolis" pinout, which swaps around a couple pins.
 

clh333

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Thank you for your replies.

The drives are all Tandon TM-100 2A. Two are from a recently acquired IBM PC XT (another thread); one of these - the B drive - is one of the suspects. Another of the culprits came from eBay: I bought a pair of drives, one was suspect.

I don't plan to use these for archiving; I have TEACs and Panasonics for that purpose. If I could I wouldn't use them at all, Tandons having the reputation that they do, but because they are full-height and fit some apertures, e.g. early Kaypro and IBM PCs, and are the only means of storage therein, I either make them serve or cannibalize them.

I'm not a drive mechanic by any means but I plan to learn: I bit the bullet and bought an alignment disk from Accurite. So far the extent of archiving has (mostly) been to copy files to HD. I've got a lot of different drives but no "gold standard", no baseline. The objective is to be able to read on a given machine what another drive masters elsewhere.

Thanks again,

-CH-
 
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