Episode 3 in my piers rocks floppies rock series:

floppies rock ep 3

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I look at another Commodore 2031LP disk drive in episode 3 of floppies rock. However, this 2031LP isn’t quite what it seems, containing 1541 internals. First I have to get it working as a 1541, before I can then mod it back to a 2031.

Timestamps: 00:00 Intro 01:48 Initial inspection 05:25 1541 testing 07:06 Speed adjustment 08:43 Inspecting the drive mechanisms 11:22 Tachometer testing 13:44 Explaining the 2031 mod 15:24 2031LP testing 17:25 2031 mod details 17:37 Main mod board 20:24 IEEE-488 connector cable 21:49 Replacement ROMs 24:04 Device number change 26:03 Wrap-up

Problem with existing drive:

  • The only problem I found with the existing drive was that the spindle motor tachometer had failed and so was driving the motor much too fast. When tested it high resistance across the winding (which should be of the region of 170 ohms). The tachometer was still generating an AC signal but at 280mV instead of the 2.8V of a working unit.

I intend to fix this in a future video - for this video I replaced the drive mechanism with a known good one from another 1541.

You can find the 2031 patched top (E000-FFFF) ROM for use with a 1541 bottom (C000-DFFF) ROM here: https://github.com/piersfinlayson/piers.rocks.video.support

You can find more information about the mod here: http://www.zimmers.net/anonftp/pub/cbm/documents/projects/ieee-488/vc1541-ieee.tar.gz

The service manual for the 2031 (both HP and LP) is here: http://www.zimmers.net/anonftp/pub/cbm/schematics/drives/old/2031/2031_Disk_Drive_Service_Manual.pdf

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