Posted By
rossi
on 2023-08-10
12:36:18
|  Re: 1551 diagnostic / 1551test.prg / repair possible?
(sorry for the third try)
Hi together,
since this is my first post to this forum, I would like to take the time to introduce myself first, please apologize therefore if this post is a little bit more lengthy and not straight into the topic. I'm in my early 50s and live in Germany, Bavaria to be a little bit more specific. I nowadays work in the rail industry, being responsible for onboard WIFI services. As a kid I used to own a C16 expanded to 64k (done with the help go my uncle, due to my - still - bad soldering skills as a software guy) with a 1551 drive. Unfortunately I had to sell those when I upgraded to an Amiga 500 in 1987, which I again had to sell to chip in my own part to a high school exchange year in the states. A couple years ago I obtained a Plus/4 mostly due to nostalgia and recently finally managed to actually start to tinker with it again. I must admit, my memory is so bad, that I had to read the manuals again for refreshing my knowledge of the basic instructions. My nickname in those times had been rossi, thus the "username" for this posting.
Now getting finally to my current topic, I just managed to obtain a 1551 for an outrageous amount of money, which according to the seller had been never used an still came in the original packaging. The drive powers on and the error led is off. However when I try to read the directory of the included test disk I get the following error: "27 READ ERROR 18 0". To verify that it's not the disk I bought another test disk and a NOS package of blank disks. However I get the same error with the second disk. The leads me to suspect the culprit might be the drive and not the disk.
After a some research I stumbled upon the 1551TEST.PRG from Rob Clarke. Thanks at this point to Rob for writing and sharing this tool. However I didn't manage to find any documentation for the tool.
I have additionally an SD2IEC on address 9, which I use to actually run the tool, as I have no way to transfer the tool to a cassette.
To further diagnose the issue I now try to understand the output of the tool. I get the following results from the different tests (I only list the faulty ones):
1. Test: Default register values at $FEC0: Port A (R0): 85 Bad Stable
9. Test: Internal drive pull-ups: Port C (R2): 192 Ok Unstable
The test program tries to read from the drive and exits with "21 READ ERROR 18 0".
As I'm totally way over my head here, I would kindly ask for help to figure out what's wrong and how to potentially fix, if possible.
Btw, theoretically I could still return the drive to the seller until August 21.
Thanks in advance for any ideas!
Cheers,
Marcus aka rossi
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