5.25 Tandon weird issue
I picked up some used 5.25 drives and one is a Tandon that I think is a TM50-1 drive. There's several Tandon labels on the drive and none have a model number. It has the look and feel of the TM50 drives including needing a U19 jumper for DS0/1 select.

It of course it needed the lead screw and head rails cleaned and lubed upon arrival.

Testing the drive after cleaning and replacing a 4.7 uf cap (busted by heavy handling) and SCP shows that it is a low density 48 tpi drive. Max. track utilities test is 43 or 44 tracks, erase function erases 0-39 tracks correctly using the full stroke of the head, media test is a bust since I'm using a known damaged diskette (used for 1st testing a drive), but it attempts to test 0-39 tracks if I take the time to tell it to ignore all the errors. Drive speed is 300 -301 RPM. So far all seems okay or within reason? However, if I try to make a copy the drive the SCP seems to be double stepping the head and it crashes into end stop at about track 22 as indicated on the SCP software.

Utilities moves the head correctly, but copy goes nuts and double steps the head. What am I missing?


The SuperCard Pro software doesn't "show" what type of drive is connected. That is physically not possible. It is the user's responsibility to set the drive type using the pull-down menu.

What do you have the disk type set to? The disk type and the how you have the drive set in the pull-down menu (48 TPI vs. 96 TPI) determines how the head is stepped.
Bad wording on my part for saying "shows" vs. "set" for 48 TPI.

In reality it wasn't set for 48 TPI! Going back fresh and after a good night's sleep and problem was solved by changing the setting to 48 TPI. I guess it was a combination me of being a newbie with the software, and also seeing what wasn't true, had me seeing 48 TPI was selected. When clearly 96 TPI was dimmed and check marked. As they say, you can't fix stupid. Or operator error. Angel
Glad you got it resolved! Smile

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