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1541 troubles

PostPosted: Mon Sep 24, 2018 8:09 pm
by rdedr
This is a bit of a longshot, but hope someone can help me with the reparation of a Commodore 1541 disk drive and perhaps a 1541-II drive. Below I'm explaining what is wrong and what I've tried to date.
The 1541 is having troubles with reading and formatting floppies. Tested a bunch, but none of them came back with a directory (load"$",8). It didn't even say loading, just stopped with searching.

My next step was to get the head cleaned and greasing the rails with some WD40 based on some Youtube videos. Unfortunately this didn't help. Getting a bit desperate and not having spares to swap chips or the board I procured a $20 1541 diag cartridge with several test programs on it. That was an useful investment, should be standard in toolkit of every 1541 owner.

After a lot of testing and inconsistencies between floppies, a trend emerged. The disk skipped track 18 which is where the directory resides. It also had trouble reading tracks beyond 25 and skipped the higher tracks randomly at times or just stopped without errors. With this knowledge I managed to load some files from floppies by just reading the first file which worked. This proved that at least some of the drive still worked and e.g. the head was not damaged badly and a good number of floppies are likely still ok.

Next step was trying to work with alignment and speed adjustments. The Youtube videos are very helpful on this topic, however any way I changed the alignment or the speed the results were the same or worse when going into extreme settings. Of course I tried several different floppies, commercial and my own ones. Also tried formatting which always fails somewhere halfway.

Having heard of the head mechanism worn out or bend may cause issues with reading the higher tracks beyond 18 I tried some careful pushing/bending while reading, formatting but also to no avail.
By now I have spent about 4 weekends and many hours without being able to fix this. Perhaps someone has more ideas or tips to try without swapping chips or the board.

Or maybe better, someone who is able to repair these drives and get them back in a working state. Happy to drop them off and pick up anywhere in Northland or Auckland region.
Sending them overseas to Europe will cost about NZ$80 each drive one way. Basically not really worth it. Ordering replacement chip(s) or entire board is an expensive shot in the dark, as it is still not clear what is wrong.

Secondary option I'm considering if repair is not feasible is someone in my region who is fine to have me reading my floppies on their C64/1541 and transferring them to my Ultimate II SD drive. Something I should have done years ago, but kept on postponing. A few important floppies with my own work have been backed up to harddisk years ago though so not everything is lost.