Good advice, Gary. Guess I'll have to look through my piles of Commodore drives one of these days to see if any of them have that issue; we just had a discussion about this on one of the Commodore lists and ISTR that it was mainly only one make (Mitsubishi?) and one or two specific caps that had this problem.
FWIW, worst case you can replace the DVI drive with pretty well any half-height double density 5.25" drive (or two) as long as it fits mechanically; I replaced mine long ago with a pair of Teacs just because I wanted a matching pair and couldn't find another drive like the original. In fact you could even replace it with a 3.5" drive if necessary and you had the required adapters and a 3.5" DD boot disk. m ----- Original Message ----- From: Gary Hammond To: [email protected] Sent: Friday, October 27, 2017 4:17 AM Subject: Re: [M100] DVI cable My DVI suffered from very similar issues when I first tried to use it. The 5.25” drive is the same drive family as the notorious C64 disk drive that would fail from the capacitors leaking toxic crap on the PCB which subsequently eats tracks. I had to replace the caps and manually re-run some of the tracks to get it working again. From memory, the tracks that it eats are those relating to the read/write circuitry which is why the seek works but no cigar on the subsequent read. Have a close look at the part of the PCB that is the closest to the front of the drive. From: M100 <[email protected]> on behalf of Brian White <[email protected]> Reply-To: "[email protected]" <[email protected]> Date: Friday, 27 October 2017 at 5:21 PM To: "[email protected]" <[email protected]> Subject: Re: [M100] DVI cable Well now I've added the twists to my cable and the encouraging development is that my M100 no longer crashes from using it. :) But alas the dvi still does not boot beyond the step where it asks for the system disk. The drive light comes on early like the manual says to expect, the head seeks a tiny bit at power-on, but the main motor does not spin, nor does anything else happen in reaction to closing the door latch. Oh well. I have another dvi on the way in, and I might just possibly be able to diagnose this one eventually. I can at least try the drive by itself in another machine, and test another drive in the dvi, and test if the dvi is activating the motor-on signal on the floppy cable. Since the dvi does "boot" it's own firmware enough to display the first two prompts, that does suggest a lot must be right. Cpu, ram, roms, etc. Me and a meter and the service manual have a long date some weekend I guess. :) -- bkw On Oct 27, 2017 12:06 AM, "Mike Stein" <[email protected]> wrote: You're welcome ;-) Why do I bother... ;-) ----- Original Message ----- From: Randall Kindig To: [email protected] Sent: Thursday, October 26, 2017 11:21 PM Subject: Re: [M100] DVI cable Brian, thank you so much for all the detailed information. It’s much appreciated that you took the time to document what you did. It’s great when members of these groups freely share information and are happy to help others. I’m hoping Ian Mavric will take this information and create a working cable. Randy Kindig host Floppy Days Podcast floppydays.com On Oct 26, 2017, at 4:48 PM, Brian White <[email protected]> wrote: I just recieved this new info from a member on the facebook group. http://tandy.wiki/Disk/Video_Interface#Work_in_progress... This cable looks home-made too, but he claims he knows it works and has used it himself. Since he not only used the numbers but also a clear picture and description of plain physical location, there is no ambiguity about it. Randy: THIS would seem to be the answer to your question finally. You can duplicate this guys cable using the same parts I linked to on that same wiki page. But ignore my tentative directions and pictures and go by Ted Saari's. (I'll update my directions and pics when I have actually verified it for myself, until then I'll just leave the "not yet verified, see below" note on mine. But it looks like this is what it's going to end up being.) It flies in the face of what I said so far! :) His cable has twists in it, so that tells me that his DIP connector is pinned the same as mine, because I will have to make twists like that too, in order to get the pinout he describes. The first cable I made was actually like that, and didn't boot either, but I convinced myself it was because the twists were wrong and I cut the end off that cable and scrapped it. So, I predict I still won't get my DVI working even after I duplicate this supposedly known-good example. I have another DVI on the way in, so maybe that one will work. Glad I ordered 10 dip connectors instead of 1! -- bkw
