Floppy drives not working correctly on Model 4

Diecrusher · April 28, 2016

I am restoring my Model 4 and have installed 1 Teac 55B 5.25" floppy drive and 3 3.5" drives.

1) The Teac drive was working fine and reads disks with no problem but is now refusing to finish formatting disks by throwing up verify errors. I replaced with another Teac drive and I am getting the same errors so this seems strange that both drives would be bad. I am fearful that perhaps both drives have worked themselves out of alignment and am not sure what to do. Any ideas? I have an oscilloscope but don't have an alignment disk so I am not sure of my options. I put my old original texas peripherals drive back in and it works fine with no issues.

2) The 5.25" drive I know takes both +5v and +12v for power. I have separate new +5v and +12v switching power supplies that I would like to place in the Model 4 so I can run this drive without the stock power supply. When I hook the 5.25" drive to the stock supply I seem to get CRT glitches when accessing the disk hence my reason for by-passing the stock supply. Is there a way to feed +5v and +12v to the drive from separate power supplies? I know it is not as simple as hooking both of the power supply's neutrals together.

3) I have tried hooking up 1 of the 3.5" drives (jumpered to dsk0) to the Model 4's external floppy port and it is not being recognized. Cables are oriented correctly. My Lotharek HxC connected to that external port works fine. I have tried different 3.5" drives and 5.25" drives and get the same problem with the same cable that I used with the HxC and cannot get any floppy drive recognized. I've tried cables with all of the pins intact and a cable with pins 12,14 and 32 pulled as stated in the R.S. manual and still can't get the drive recognized. Termination issue? I am about ready to give up here, put the stock 2 drives back in and forget about it.

Any help would be appreciated.

Edited April 28, 2016 by Diecrusher

Caterpiggle · June 14, 2017

Can you tell me what is the command for load directory list ? What is the exactly command for load & save programs ? For directory , I thought of DIR, CAT, CATALOG , all failed due wrong command. Yes, for Model 4.