Commodore.ca: The PET, VIC, 128, 64 & More Forum

Hi, I'm new here. I'm having a problem with a Commodore 4040 dual drive. This one came out in the late 70's I believe. One of the drives, drive 0, works and the other one doesn't. I've always had a problem since I bought it used several years ago. A week ago cleaned the heads with isopropyl alcohol and it worked for a while and I thought it was fixed. The problem is that the disk spins, but the head doesn't move at all. The drive is okay because I swapped drives and it works. It must be one of the controller boards. There are two circuit boards and I don't know which one has the problem. I reseated all the cables. The one board has some socketed chips and I reseated them. I'm wondering if anyone has any idea what would cause this.

Hi. Have you tried pushing the head on the rails to make sure it moves freely and isn't jammed, with power off, of course? I have had a few drives get stuck that way from storage and the grease that was on the rails turning into a glue like substance. I little bit of cleaning the rails with Isoprop. and a small bit of grease and it has revived a few stuck mechanisms.

I did mention that I "swapped the drives". Actually I managed to switch the cables so drive 0 was drive 1 and drive 1 was drive 0. The working drive stopped working and the non-working drive started working. The drives are both okay. It's something else. Thanks for the suggestion anyway.

Yes you did mention you swapped drives and I guess I was having a brain fade that day. LOL. Sorry. I don't know what else to try besides swapping chips. from one board to another.

I've decided which board is probably bad. The small board seems to control the input from the two drives and sends it to the bigger board, which takes the input from both drives. If neither drive worked it would probably be the big board. There is a big board for sale on ebay right now, but, like I said, I have reason to believe that isn't the one. I will wait for the little board to come on sale on ebay (or someplace else). It's only a matter of time. Having one of the drives working is better than none of them. The thing I'm trying to do is get programs and files from an emulator like "Vice" and get them to the real B500. The 4040 is "mostly" compatible with the 1541. So I can get files from the low-density disks to either the medium-density 8050 or high-density SFD-1001, both of which I have.

It may be the driver circuitry on the controller card. Not able to source enough current..do you have a digital multimeter? Power it up and start checking voltages.

Ftp://www.zimmers.net/public......
Has schematics and maintenance Manaus for commodore 4040 drives.

We have the 4040 schematics available: http://www.commodore.ca/manuals/funet/c ... dex-t.html