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Need Help With a 1541 that won't format

M

Mochatea396

Experienced Member
Joined
Feb 9, 2021
Messages
133
Location
Hudson Valley, New York, USA
Hello group,
I'm fairly new to the Commodore community and am still learning about these systems. I picked up 2 untested commodore 1541 drives cheap. one is an Alps and the other is a Mitumi. The Alps is working fine after a good cleaning but just getting into the second one tonight I'm seeing its not so fine. I cleaned the head and rails and the head moves free manually and the drive powers up normally. Connecting it a Zoom Floppy, it gets recognized no problem. When I put a disk in, I noticed that the drive doesn't respond to me inserting the disk. When I try to format the disk with the Zoom Floppy (as I format disks with my other drives) I hear the head go back, the red light comes on, spins for about 5-10 seconds, I don't hear the head tracking, then it stops spinning but the red light will continue flashing until I reset the drive. I've tried the serial cable in both ports and it's a known good cable. Tried several disks too, and I know they're good disks. I have experience with Apple disk iis experiencing similar issues but I'm going to need some direction with the 1541 so I'm not going at it barking up the wrong tree.
Thanks group
Randy
 
The 1541 and 1541-II don't have an optocoupler to detect the insertion of a disk. The 1541C does. So you see that mentioning just "1541" is not enough. So the first one is a 1541C and the second is not, or is broken.

Have you tried reading disks with the second one? (you didn't mention it) If that goes well, then the problem can be brought back to the writing part: head or electronics.
 
The drive probably suffers from rotten coils in the read/write head, which is sadly normal for Mitsumi/Newtronics drives. You can simply check with an Ohm meter. If you get no reading between a pair of wires going to the head, the drive is toast. It's not repairable.
 
Timo W. said:
The drive probably suffers from rotten coils in the read/write head....... It's not repairable.
Click to expand...
People are doing some really clever/crazy stuff for repairing roasted old hardware;
can one substitute head 💀from a more modern FDD to 1541? Dr. Frankenstein
used Abby Nomarl's head 👻 and it was successful!

ziloo 😊
 
No, you can't. You can take it from another drive of the same type, but then you could also just swap the complete drive anyway instead of risking to brick another one. Also, getting the alignment right after swapping a single head is something impossible to most people.

Just stay away from the Mitsumi/Newtronics drives.
 
Sometimes you can luck out and find replacement Alps drive mechanisms on line. I fixed a 1541 with a dead Neutronics head doing that. The board was fine, but I was having the same issues you were. The boards should we universal so if you wanted you could always swap the board out between the two and see if the Alps drive still works. If it does, you have a spare board then.
 
Thanks everyone for your responses. I did hear to stay away from the Mitsumi drives. only after the fact of buying this one. I will test the coils on the head today. I connected the drive to a C64 last night and the drive wasn't able to read a good disk. I was able to load "1541 Diagnostics" from a Versa64cart I made and running the alignment test, I got the same screen I get when checking a known good drive. Goes through track by track and I can hear the head stepping as it should.
 

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I just tested the coils on the head and I get no reading on anything I coil to the red wire. Labeled 5. The other 3 show good readings between them. Only the red #5 is dead. The head is clearly bad. So it looks like this problem is very common with these Mitsumi drives and why people say stay away from them.
 
Sorry to hear that you got a dead drive, but look on the bright side. You have one working 1541 and a spare board if you need to fix that one
 
The drive only cost me $25 so not a great loss there. lesson learned. Stay away from Mitsumi. Wish I read that a week earlier. Oh well move forward.
Thanks again for the replies and help.
 
Mochatea396 said:
The drive only cost me $25 so not a great loss there. lesson learned. Stay away from Mitsumi. Wish I read that a week earlier. Oh well move forward.
Thanks again for the replies and help.
Click to expand...
Yea, my first 1541 was a Mitsumi, but I lucked out and it worked. I got another one for $20 on eBay that said it worked, but when I got it, nothing, same issues you were having. I was talking with Ray Carlson via eMail and he was the one that said that to me, and sure enough I tested it and that was the issue. I did luck into an Alps drive on eBay for cheap and that got it working. I do have two working Mitsumi drives in my collection I am always on the lookout for Alps drives to swap out with as a bit of future proofing. But yea, you learned something knew. And remember, knowledge makes you 50% combat ready.
 
Did you do an actual resistance check to determine if the head is bad or not? Someone can supply the correct readings or you can use your working drive as a baseline. Without verifying the readings its speculation not troubleshooting. i.e. another stupid discussion about MT ram chips....
 
Out of 5 Mitsumi drives that previously worked, now I have only one. Very common failure. They fail sitting on a shelf.
 
norm8332 said:
Out of 5 Mitsumi drives that previously worked, now I have only one. Very common failure. They fail sitting on a shelf.
Click to expand...
I had 3 Mitsumi's that worked, down to two, already replaced one with an Alps. I keep scouring eBay for just the Alps drive mechanisms to replace the Mitsumi's as I can find them. I do have a 1571 that is a lot more reliable and place on stopping my drive purchasing if I can get a 1541-ii that isn't stupid expensive.
 
robert_sissco said:
I had 3 Mitsumi's that worked, down to two, already replaced one with an Alps. I keep scouring eBay for just the Alps drive mechanisms to replace the Mitsumi's ......
Click to expand...
1- Was Alps brand made in Hong Kong?
2- Are all Mitsumi FDDs (1541, 1541 II...) equipped with swivel latches?
I want to know how to distinguish between the two from photos!
 
2) Yea, the Mitsumi are the swivel latched and the Alps are the push latches, not sure where they were made however.

As for the later models, I think on 1541-ii's the issue was resolved, not sure on the 1541c's however
 
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