Ha! I did the Meguiar's Plast-X trick just last night on a 1541-II I've been messing around with. Old bad disks were depositing black contamination that I couldn't get off with isopropanol or rubbing with cotton buds. I decided that the head surface was plastic, and the deposits must be down in scratches that accumulated in the head over years of use. I knew that Plast-X is a super fine and mild abrasive, almost to the point of uselessness on most plastic, but it could scrape the deposits out of there and also perform some amount of smoothing to attenuate the scratches at the same time. Worked perfectly! And the smoother head surface should be kinder to the disks too. I wasn't sure it would be OK to do, so I kept quiet about it. Good to see someone else thinks the same way!
That thing's MASSIVE, it's nearly as big as the C64, just shows how much technology has moved on since the early 80's you only have to look at the 1541U-II or SD2IEC.
No wonder the 1541 and 1541 II's was more expensive than the C64 itself back in the day looking how many chips and stuff are inside these drives. I bought my 1541 II used back in the day. But even then it was not much cheaper than what I paid for my C64 with the tapedeck. Great video. I always appreciate your repair videos. Keep em coming! :)
+Mats Larsen Yes, it's amazing just how much is in these drives! You could actually turn the drive into a computer with a bit of modding! Thanks for the nice comments =D
+Mats Larsen Yeah, the 1541 is literally a computer. It has its own RAM, ROM, 6502 CPU, and two 6522 VIA chips. You can even use M-W (Memory-Write) and M-E (Memory-Execute) commands to load short machine language routines into its limited 2k of RAM. The 4040 disk drives for the Commodore PET actually had a *dual* CPU, with one handling the GCR encoding and decoding, and the other handling everything else. That's one of the reasons the 4040 was so much faster. (Well, that, and the 4040 was parallel while the 1541 is serial.) Having said that, the 1541 would have been faster except for one thing: A flaw in the 6522 VIA, which Commodore never fixed. Initially it was to use a hardware shift register, but the flaw forced Commodore to resort to "bit banging" (software) instead, so the 1541 had a transfer speed of about 512 bytes per second (by comparison, the Atari 810 had a transfer speed of about 1000 bytes per second, and the Apple Disk II had a blazing speed of about 15,000 bytes per second.) It's no wonder why speed-loader cartridges like Epyx FastLoad or third-party hardware mods like JiffyDOS were so popular.
I have a far older Commodore disk drive - the 2031 which uses the GPIB (IEEE-488) bus instead of a serial bus. Unfortunately it never worked quite right. It would format a disk just fine and then would read it just fine - for a while. But after a few weeks it suddenly would start giving errors and refuse to load anything. If you re-formatted the same disk, it would behave itself again for a few weeks until becoming unreadable again. Repeat ad infinitum. I considered the possibility that it was a head alignment problem, but when I looked inside the drive casing I couldn't find any obvious way to adjust the head alignment, and all the fastenings which I could find associated with the heads seemed to be tight. So, it's sat out in my garage for about 20 years unused. I recently hauled it out again, and it looks like I was just in time to save it from terminal corrosion (or at least I hope so).
Thanks mate this video helped identify a fault with my drive :) The red wire to the head is broken I hope to run a new wire to replace the broken conductor.
Watching your video again, at time 16:36 you mention transistor Q5. It's right next to the J3 jumper that you talked about (for the r/w head photo sensor). My J3 jumper is currently open, but I'm tempted to close it to see what happens.
just watched this while working on a 1541C with read write problems. the red wire from the head gave 15k when connected to the yellow, I guess it's bad !
I've also got a load of these drives, love the big clunky things! I know you eventually realised it was the damaged floppy disk eventually, but a big hint is at 18:50 where the format result reports only '65 blocks free'. For a formatted floppy disk that should be showing 664 blocks free. This is common on damaged or old disks, at least when you have ruled out head dirt or alignment issues! Anyway as always a great video! I also have a couple of the Oceanic (aka Excelerator) OC-118 floppy drives, one of which I can't get to behave for love nor money and there seems to be no way of aligning the head! If you ever come across one of them I would love to see a video about it! Regards
+Andy Mason I do like them - really well made imo, I love the build quality! What seemed to be happening when formatting - there's no notch cut out of the disk edge, so whilst it looked like it was formatting I think it was write protected. The bytes shown at the end was based on the existing contents of the disk after it read the FAT. I noticed the same thing happening tonight when trying to format the working side. I presume the C64 doesn't tell you if its write protected? There's a chance I have an issue with write capability yet, I need more disks to arrive tomorrow before I will know.
Really interesting you had to go so far as to demagnetise the heads... I've got a few 1541's here and one of them is 80% working but doesn't write the higher tracks well enough to read back on another drive despite the alignment being as good as I can get it. I wonder if this drive of mine doesnt need demagnetising or the heads super duper cleaned like you've done to this one? Ive wasted too many hours trying to get it right already, I can't give up on it now! Thanks again for the great vids and information GadgetUK! -Mitch
+aphexteknol I would give it a go! The other possibility is you've got a problem with the head wires (which you can replace) - when the heads move a certain distance the wire bends a certain way and you get an open circuit on one of the wires, meaning you either lose the read head, or the write head etc. It does sound like that could be your problem.
Also have a broken 1541 Mitsumi drive here and I will try to fix that at some point. In the meantime I have stolen the MOS 901229 chip out of that thing to fix the broken SX64 I got. ;-)
+bwack Thanks =D It looks good as new to be honest, with hardly any wear on the belt and the head looks like its brand new now. Really pleased with this drive, wasn't bad for £15!
+bwack The schematics on Zimmers had a different version of the gate array chip, and that diagram you mentioned (1541C.gif) is for the 1541B - if you look top right on the diagram it says 1541B, and it has component differences on there. Note the 7404, my board doesn't have a 7404! Maybe its almost the same, I am just not sure if that gate array (the 40 pin package) is the same between boards, since they seem to have completely different part numbers.
+Jorge Carvalho Hehe! I wouldn't say I am a 1541 god lol, There are a lot of different revisions / models and I've hardly scratched the surface on the different types of faults you can get with these drives. They are nice drives though, I do like them I have to admit.
To write on the reverse side of these single-sided disks, you need to cut a notch. Back in the day, you could buy a disk notcher that did it for you, like a hole punch for paper. Otherwise, just reverse the disk side, place it against another disk, and that gives you a guide to cut a notch out. In terms of design, the 1541 mk. 2 , was styled to better match the 64c, and smaller as the power supply was moved outside to an external unit
+MarkTheMorose Ah, of course!! I was thinking that no hole = write mode, but actually its the inverse! Doh!!! That makes perfect sense now you mention it =D
GadgetUK164 :) When you bought new 5.25" disks, they came with stickers to put over the write notch, to prevent them accidentally being erased. Other disk formats were the opposite, though I no longer recall which.
+MarkTheMorose I've just had a look at the disk and it has no holes at all on either side edge. This means it should be writable I think. So it does like like side B is write protected in software. I will do a bit of research now to see what commands there are for doing things like that. I vaguely remember reading somewhere that if a file name contains < in it the file cannot be altered.
+MarkTheMorose Just reading online now suggests that the hole means you can write. Which is even more strange since there's no hold on side A or B, yet A will format, B won't allow it. Something weird going on with that disk I think... I might just cut 2 holes in it and try with that.
Another great video! It would be interesting to see if this unit will work after a few months of use and storage. Did any Commodore hardware have cable ties ? - just trying to figure out if that board had been swapped out like you mentioned ? Having multiple problems when trying to solve one fault can be a right headache so well done for putting up the time to keep trying. Look forward to the next video.
+A Leadbeater It will work after a few months - absolutely guaranteed! The problem was definitely bad contaminants on the head and it did need de-magnetising. I've fixed ST and Amiga Floppy Drives the same way before and they've lasted years. I think the thing is you tend to think that if the head cannot read after having a few cleans then it must be faulty. The one way its really faulty is if the windings are either shorted or gone open circuit. They aren't as analog as people think when it comes to wear.
Built to last ! - Although as a kid i had about 3 Commodore 64's (brown) and they all seemed to die, they were forever being fixed in the electrical shop. I did practically live and breathe Paperboy, so too much gaming was probably to blame. What other fix projects have you got lined up ?
+A Leadbeater My Spectrums were the same back then lol - in and out of the repair shop. The big problem for me was I had the Interface 1 and micro drive, and the connection would always come loose and kill the ULA =/ I've got some odds and ends that I am working on at the moment, an Amiga mouse, Amiga RGB lead, 3 or 4 SNES (2 fixed already, not sure if I can make one out of the other 2 yet), and loads of bits and bobs that I need to finish off. My problem is I start something and then finish it 12 months later lol.
Great video! How did you demagnetize the Head of the disk drive, and what did you use to lubricate the drive? What specific areas did you lubricate? I would think that this would just attract dirt & dust and jam up the drive. Thanks for taking the time to answer my questions, I appreciate it.
+ResistanceIsUsefull I showed the demagnetizer in the video! Basically put the metal surface of the demagnetizer close (almost touching) to the head, you can feel it vibrate. Move it in circles for several seconds and then pull it away. With regards to lubrication - in 2 places, on the shaft of the stepper motor (whilst the drive is running upside down), you only need a tiny amount. And on the rails that the head slides up. Yes, it does collect dust over time, its best to clean them first as they will likely already have dust on them. They are lubricated from manufacture!
Hi, I have the exact same Neutrionics drive and the 251854 PCB assembly as you. I'm getting a 21 read error 1 0, and 74 drive not ready 0 0 messages. I measured the resistance on the r/w head windings (with P4 r/w connector block disconnected from the PCB board) and got almost identical Ohm values to you. However, I'm still getting the read error. I've cleaned the r/w head with alcohol (it's now gleaming). And I also cleaned the surrounding area of the r/w head, in case there were any magnetic particulates as you mentioned in your video. Unfortunately none of this worked. I noted the colour of the winding cables are the same on yours for the connector P4 r/w connector block (and in the same order when looking at the drive from front to back...working left to right they are red, yellow, black, blue. One curious thing I noticed though is that the P4 connector block has pins 1 and 5 identified on the circuit board AND on the connector block. But, they are connected in reverse! Pin 1 on the block is connected to pin 5 on the board etc. However the key pin (the one that's not used is in the correct position - on the PCB board it's pin 2). In other words, mine is identical to yours in every way, yet the pin numbers on the board and on the connector block are reversed (i.e. 1 is connected to 5, and 5 is connected to 1). I assume that yours is the same. I couldn't see it properly in your video. I haven't noted any other issues with how the drive operates - when you switch it on, the green led stays on, the drive spins (red led lights up), and after a few seconds the red led goes off and 2 seconds later the drive stops. The drive tries to format by going to block 1, working its way to block 35 and then back to 18. It doesn't actually format though. When I run the 1541 performance test using the 1541 diagnostic cart, it fails on read errors, but passes the mechanical test. The other obvious issue is the speed test gives an error almost every time. At one point while spinning I noticed that for a split second it did register 298.7rpm, so I'm happythe speed is working okay, it just that the r/w head is not collecting the information correctly. The alignment test shows '0 for on track %', and '0 for between track%' for all 35 tracks. When incrementing the track from 1 to 35, it registers all tracks read as track 1 (even though I can see that the head is clearly moving from 1 to 35. At one point, I did see the some of the tracks read 100% (for about 8 in a row), but this was never again to be repeated. If it's an alignment issue, it should format and read okay for a blank disk, but possibly have trouble reading other disks. As the Neutronics drives have a very poor track record with their r/w heads, I reckon' that is the issue. I don't have access to a demagnitizer, but was surprised to see that that made a big difference in your case. I haven't seen too many people fix their drive issue by demagnitizing the head, but I'm sure you have more experience of this than I do. Anyway, I would be interested to see if you pin-outs on P4 is reversed also. And any other suggestions you have for me would be most welcome. Your vids are great by the way - I've subscribed to your channel. All the best, Alan.
It does sound like the read head from what you've described! It could be component(s) that sense the read though - ie. hybrid or ASIC etc. My bet is on the head though. Regards demagnetizer, yeah - something I worked out 25+ years ago, no one else even tries it, that's why you've not seen it anywhere else lol =D I would suggest cleaning the head with plastx or novus (plastic polish), to get the head surface super clean, and try demagnetising it. The reason demagnetizing can help is if 1 partical from a disk surface somehow gets wedged into the head surface, cleaning may not remove it - and that can influence the field read by the head from that point onward.
Nice video mate, I love those type 1541, becase I like the way close the floppy door. I don't like the way the older 1541 do. Also do you know that those short board 1541 have a another type of drive rom? They change it to do that the reading head go to track 0, the older 1541 drive rom and JiffyDOS don't do that.
Haha, yeah - not good for ESD but good excerise for when you've been sitting at a desk all day. The irony is there's a table right next to where I film - it never gets used for anything lol.
Off topic a bit but I wonder what it would be like to align a 1541 drive? I did an Amiga 3.5" drive a few years back "by hand" and it literally took me 4 hours to repeatedly adjust the head position to get it to read/write perfectly across all the tracks. Absolute pain but not the proper way of aligning it I guess lol
+Aron Gooch Yes, I suspect its similar on the 1541 - I mentioned in the video I might have a go at checking the alignment and re-aligning it if required. Just need to find a disk now!
my 1541 works fine but depending on the disk being used i have to lift the casing off and help the disk in. About half way in they get caught on something and i have to put my hand in there and lift the disk. have you encountered this problem?
I have a C64 1541-II Floppy Disk Drive which I've had for years. It powers up but it won't load anything. Would you be interested in a possible repair?
+Andrew Littleboy That might be possible, you would need to point it at something that will break the beam once every pass - maybe you could put a tiny piece of insulation tape on the drive spindle underneath, so it acts as a little beam break when it rotates. I've since ordered an alignment disk, so I will see how I get on with that, but to be honest I think its pretty much within spec. I've done a lot more testing this afternoon and everything works fine so far.
+The Highlander I use something like this:- www.ebay.co.uk/itm/New-8-Pure-Copper-Memory-Cooler-Heat-Sinks-HeatSink-For-IC-DDR-DDR2-DDR3-RAM-VGA-/350687630950?hash=item51a69c9666:m:mY9NqTBsFmnqyZBVxj1U4xA I will be ordering some for my 1541 at some point! You need to put 2 or 3 of them in line due to their small size, but they do the job really well!
+GadgetUK164 It's my boyfriend who does the electronic stuff. I just sit and watch! But he is very much into retro computers (Commodore64, VIC20, Sinclair Spectrum etc). He loves your videos and has cleaned and demagnetized the heads in the 1541, like the machine in your last vid. It now works perfectly, and we can play some of the old games again. Warmest regards and best wishes Wayne and Nina.
+Nina Evans Great stuff =D Glad you got it working! Thanks for watching and commenting - It's always nice to hear that someone picked up something useful from my videos! =D
Sounds like you have the schematics for "1541 late"? Or the service manual is refering to that revision.. You need 1541C (the latest), in that schematic there is no Q4 and Q5 because all of that stuff has been baked into the hybrid circuit I think. Check Ray Carlsens website for the schematics. I had trouble finding it back in May when I repaired mine. I was searching all over the Zimmerman archives, but Ray Carlsen has a good directory strucure. personalpages.tds.net/~rcarlsen/cbm/1541/
+bwack Thanks, it looks like those 2 transistors on mine are for the +5VF. And I think you are right, looks like +12V just goes into the hybrid and +12VF must be internal only to the hybrid. I wonder how reliable those hybrids are. I did wonder what my approach would be if I suspected a fault on there, perhaps there's a way of removing the paint / acrylic coating without damaging it too much. If so it would probably be possible to repair it?!?
Right :) Looked at +5VF yesterday in the "1541C", and compared it to "1541 Late", which does not have hybrid,and there they call that voltage for Vsw instead.. It is only used on analog parts.Most likely to keep the digital switching noise down to a minimum on the power supplied to the parts that condition the small pick-up signal into a digital one. Not sure if you can remove the coating. Maybe acetone bath, but what a smell.. It looks thick.. I wonder why it was coated ? Did they use (package-less) die on board like the blobs you see in calculators ?
+bwack Very interesting! It looks like it has SMD type resistors, caps, transistors on it. I know Kipper2K took one to pieces from the Amiga hybrid. He built his own replacement for that.
Wow. I've heard about Kipper2K and his vampire accellerator. Awesome. This retro scene has some very talented people still developing :) You could take the analog circuits in the earlier 1541 revisions and make a compact hybrid board for the latest 1541. If someone has the time and will do to it.
Yes, there are some really smart people in the Amiga scene! I cannot wait for the Vampire 1200 to arrive. I think the 500 model is next, will probably pick up one of those I think.
Or one of the VIAs. There are two 6522's on there, could you try swapping them around (make sure you get pin one in the same position as its marked on the PCB). If the behaviour changes after swapping them around you probably need a new 6522. You can replace those with Rockwell 6522 chips which are readily available on eBay.
GadgetUK164 idk how to remove chips, i tried it with a screwdriver but they didnt moved a bit (maybe a screwdriver isnt enougth for chips lastused in i guess 1990
Ha! I did the Meguiar's Plast-X trick just last night on a 1541-II I've been messing around with. Old bad disks were depositing black contamination that I couldn't get off with isopropanol or rubbing with cotton buds. I decided that the head surface was plastic, and the deposits must be down in scratches that accumulated in the head over years of use. I knew that Plast-X is a super fine and mild abrasive, almost to the point of uselessness on most plastic, but it could scrape the deposits out of there and also perform some amount of smoothing to attenuate the scratches at the same time. Worked perfectly! And the smoother head surface should be kinder to the disks too. I wasn't sure it would be OK to do, so I kept quiet about it. Good to see someone else thinks the same way!
Thanks, awesome you got that drive working =D =D
That thing's MASSIVE, it's nearly as big as the C64, just shows how much technology has moved on since the early 80's you only have to look at the 1541U-II or SD2IEC.
+FourX2k3 I know lol! It's a nice piece of engineering though! I do like the build quality of these drives!
No wonder the 1541 and 1541 II's was more expensive than the C64 itself back in the day looking how many chips and stuff are inside these drives. I bought my 1541 II used back in the day. But even then it was not much cheaper than what I paid for my C64 with the tapedeck. Great video. I always appreciate your repair videos. Keep em coming! :)
+Mats Larsen Yes, it's amazing just how much is in these drives! You could actually turn the drive into a computer with a bit of modding! Thanks for the nice comments =D
+Mats Larsen Yeah, the 1541 is literally a computer. It has its own RAM, ROM, 6502 CPU, and two 6522 VIA chips. You can even use M-W (Memory-Write) and M-E (Memory-Execute) commands to load short machine language routines into its limited 2k of RAM.
The 4040 disk drives for the Commodore PET actually had a *dual* CPU, with one handling the GCR encoding and decoding, and the other handling everything else. That's one of the reasons the 4040 was so much faster. (Well, that, and the 4040 was parallel while the 1541 is serial.)
Having said that, the 1541 would have been faster except for one thing: A flaw in the 6522 VIA, which Commodore never fixed. Initially it was to use a hardware shift register, but the flaw forced Commodore to resort to "bit banging" (software) instead, so the 1541 had a transfer speed of about 512 bytes per second (by comparison, the Atari 810 had a transfer speed of about 1000 bytes per second, and the Apple Disk II had a blazing speed of about 15,000 bytes per second.) It's no wonder why speed-loader cartridges like Epyx FastLoad or third-party hardware mods like JiffyDOS were so popular.
I have a far older Commodore disk drive - the 2031 which uses the GPIB (IEEE-488) bus instead of a serial bus.
Unfortunately it never worked quite right. It would format a disk just fine and then would read it just fine - for a while. But after a few weeks it suddenly would start giving errors and refuse to load anything. If you re-formatted the same disk, it would behave itself again for a few weeks until becoming unreadable again. Repeat ad infinitum.
I considered the possibility that it was a head alignment problem, but when I looked inside the drive casing I couldn't find any obvious way to adjust the head alignment, and all the fastenings which I could find associated with the heads seemed to be tight.
So, it's sat out in my garage for about 20 years unused. I recently hauled it out again, and it looks like I was just in time to save it from terminal corrosion (or at least I hope so).
Thanks mate this video helped identify a fault with my drive :)
The red wire to the head is broken I hope to run a new wire to replace the broken conductor.
You're welcome! Please let me know how you get on with the repair =D
Great to see the troubleshooting process, glad you got it working. Thanks
Watching your video again, at time 16:36 you mention transistor Q5. It's right next to the J3 jumper that you talked about (for the r/w head photo sensor). My J3 jumper is currently open, but I'm tempted to close it to see what happens.
Closing J3 jumper made no difference unfortunately. I'm still doing some more investigation...
just watched this while working on a 1541C with read write problems. the red wire from the head gave 15k when connected to the yellow, I guess it's bad !
=/
In Robert Brenner's "The Commodore 64 troubleshooting & repair guide", he mentions that one possible cause for drive failure is the LS7406 chip.
I've also got a load of these drives, love the big clunky things!
I know you eventually realised it was the damaged floppy disk eventually, but a big hint is at 18:50 where the format result reports only '65 blocks free'. For a formatted floppy disk that should be showing 664 blocks free. This is common on damaged or old disks, at least when you have ruled out head dirt or alignment issues!
Anyway as always a great video! I also have a couple of the Oceanic (aka Excelerator) OC-118 floppy drives, one of which I can't get to behave for love nor money and there seems to be no way of aligning the head! If you ever come across one of them I would love to see a video about it!
Regards
+Andy Mason I do like them - really well made imo, I love the build quality! What seemed to be happening when formatting - there's no notch cut out of the disk edge, so whilst it looked like it was formatting I think it was write protected. The bytes shown at the end was based on the existing contents of the disk after it read the FAT. I noticed the same thing happening tonight when trying to format the working side. I presume the C64 doesn't tell you if its write protected? There's a chance I have an issue with write capability yet, I need more disks to arrive tomorrow before I will know.
+Andy Mason I will keep an eye out for the OC-118 drives! Thanks for watching and commenting =D
Really interesting you had to go so far as to demagnetise the heads... I've got a few 1541's here and one of them is 80% working but doesn't write the higher tracks well enough to read back on another drive despite the alignment being as good as I can get it. I wonder if this drive of mine doesnt need demagnetising or the heads super duper cleaned like you've done to this one? Ive wasted too many hours trying to get it right already, I can't give up on it now! Thanks again for the great vids and information GadgetUK! -Mitch
+aphexteknol I would give it a go! The other possibility is you've got a problem with the head wires (which you can replace) - when the heads move a certain distance the wire bends a certain way and you get an open circuit on one of the wires, meaning you either lose the read head, or the write head etc. It does sound like that could be your problem.
Also have a broken 1541 Mitsumi drive here and I will try to fix that at some point. In the meantime I have stolen the MOS 901229 chip out of that thing to fix the broken SX64 I got. ;-)
+VectrexRoli SX64 are pretty rare! Hardly any around these days!
Awesome fix. Hard to find fault there. The drive must have been used quite a lot to build up muc and field..
+bwack Thanks =D It looks good as new to be honest, with hardly any wear on the belt and the head looks like its brand new now. Really pleased with this drive, wasn't bad for £15!
Also you'll find the pinout for UC4 in the 1541C.gif schematics. :) and yes it is a GAL :)
+bwack The schematics on Zimmers had a different version of the gate array chip, and that diagram you mentioned (1541C.gif) is for the 1541B - if you look top right on the diagram it says 1541B, and it has component differences on there. Note the 7404, my board doesn't have a 7404! Maybe its almost the same, I am just not sure if that gate array (the 40 pin package) is the same between boards, since they seem to have completely different part numbers.
Woow, watching this was like watching a Agatha Christie movie... mistery to the last second... great job! you are a 1541 God
+Jorge Carvalho Hehe! I wouldn't say I am a 1541 god lol, There are a lot of different revisions / models and I've hardly scratched the surface on the different types of faults you can get with these drives. They are nice drives though, I do like them I have to admit.
To write on the reverse side of these single-sided disks, you need to cut a notch. Back in the day, you could buy a disk notcher that did it for you, like a hole punch for paper. Otherwise, just reverse the disk side, place it against another disk, and that gives you a guide to cut a notch out. In terms of design, the 1541 mk. 2 , was styled to better match the 64c, and smaller as the power supply was moved outside to an external unit
+MarkTheMorose Ah, of course!! I was thinking that no hole = write mode, but actually its the inverse! Doh!!! That makes perfect sense now you mention it =D
GadgetUK164
:) When you bought new 5.25" disks, they came with stickers to put over the write notch, to prevent them accidentally being erased. Other disk formats were the opposite, though I no longer recall which.
+MarkTheMorose I remembered that, but I thought it needed the tape there to enable write, but its the other way around by the sounds of things.
+MarkTheMorose I've just had a look at the disk and it has no holes at all on either side edge. This means it should be writable I think. So it does like like side B is write protected in software. I will do a bit of research now to see what commands there are for doing things like that. I vaguely remember reading somewhere that if a file name contains < in it the file cannot be altered.
+MarkTheMorose Just reading online now suggests that the hole means you can write. Which is even more strange since there's no hold on side A or B, yet A will format, B won't allow it. Something weird going on with that disk I think... I might just cut 2 holes in it and try with that.
Another great video! It would be interesting to see if this unit will work after a few months of use and storage. Did any Commodore hardware have cable ties ? - just trying to figure out if that board had been swapped out like you mentioned ? Having multiple problems when trying to solve one fault can be a right headache so well done for putting up the time to keep trying. Look forward to the next video.
+A Leadbeater It will work after a few months - absolutely guaranteed! The problem was definitely bad contaminants on the head and it did need de-magnetising. I've fixed ST and Amiga Floppy Drives the same way before and they've lasted years. I think the thing is you tend to think that if the head cannot read after having a few cleans then it must be faulty. The one way its really faulty is if the windings are either shorted or gone open circuit. They aren't as analog as people think when it comes to wear.
Built to last ! - Although as a kid i had about 3 Commodore 64's (brown) and they all seemed to die, they were forever being fixed in the electrical shop. I did practically live and breathe Paperboy, so too much gaming was probably to blame.
What other fix projects have you got lined up ?
+A Leadbeater My Spectrums were the same back then lol - in and out of the repair shop. The big problem for me was I had the Interface 1 and micro drive, and the connection would always come loose and kill the ULA =/ I've got some odds and ends that I am working on at the moment, an Amiga mouse, Amiga RGB lead, 3 or 4 SNES (2 fixed already, not sure if I can make one out of the other 2 yet), and loads of bits and bobs that I need to finish off. My problem is I start something and then finish it 12 months later lol.
Great "detective work" on this!!!!
+Derek Baraloto Thanks! =D
Great video! How did you demagnetize the Head of the disk drive, and what did you use to lubricate the drive? What specific areas did you lubricate? I would think that this would just attract dirt & dust and jam up the drive. Thanks for taking the time to answer my questions, I appreciate it.
+ResistanceIsUsefull I showed the demagnetizer in the video! Basically put the metal surface of the demagnetizer close (almost touching) to the head, you can feel it vibrate. Move it in circles for several seconds and then pull it away. With regards to lubrication - in 2 places, on the shaft of the stepper motor (whilst the drive is running upside down), you only need a tiny amount. And on the rails that the head slides up. Yes, it does collect dust over time, its best to clean them first as they will likely already have dust on them. They are lubricated from manufacture!
Hi, I have the exact same Neutrionics drive and the 251854 PCB assembly as you. I'm getting a 21 read error 1 0, and 74 drive not ready 0 0 messages. I measured the resistance on the r/w head windings (with P4 r/w connector block disconnected from the PCB board) and got almost identical Ohm values to you. However, I'm still getting the read error. I've cleaned the r/w head with alcohol (it's now gleaming). And I also cleaned the surrounding area of the r/w head, in case there were any magnetic particulates as you mentioned in your video. Unfortunately none of this worked. I noted the colour of the winding cables are the same on yours for the connector P4 r/w connector block (and in the same order when looking at the drive from front to back...working left to right they are red, yellow, black, blue. One curious thing I noticed though is that the P4 connector block has pins 1 and 5 identified on the circuit board AND on the connector block. But, they are connected in reverse! Pin 1 on the block is connected to pin 5 on the board etc. However the key pin (the one that's not used is in the correct position - on the PCB board it's pin 2). In other words, mine is identical to yours in every way, yet the pin numbers on the board and on the connector block are reversed (i.e. 1 is connected to 5, and 5 is connected to 1). I assume that yours is the same. I couldn't see it properly in your video. I haven't noted any other issues with how the drive operates - when you switch it on, the green led stays on, the drive spins (red led lights up), and after a few seconds the red led goes off and 2 seconds later the drive stops. The drive tries to format by going to block 1, working its way to block 35 and then back to 18. It doesn't actually format though. When I run the 1541 performance test using the 1541 diagnostic cart, it fails on read errors, but passes the mechanical test. The other obvious issue is the speed test gives an error almost every time. At one point while spinning I noticed that for a split second it did register 298.7rpm, so I'm happythe speed is working okay, it just that the r/w head is not collecting the information correctly. The alignment test shows '0 for on track %', and '0 for between track%' for all 35 tracks. When incrementing the track from 1 to 35, it registers all tracks read as track 1 (even though I can see that the head is clearly moving from 1 to 35. At one point, I did see the some of the tracks read 100% (for about 8 in a row), but this was never again to be repeated. If it's an alignment issue, it should format and read okay for a blank disk, but possibly have trouble reading other disks. As the Neutronics drives have a very poor track record with their r/w heads, I reckon' that is the issue. I don't have access to a demagnitizer, but was surprised to see that that made a big difference in your case. I haven't seen too many people fix their drive issue by demagnitizing the head, but I'm sure you have more experience of this than I do. Anyway, I would be interested to see if you pin-outs on P4 is reversed also. And any other suggestions you have for me would be most welcome. Your vids are great by the way - I've subscribed to your channel. All the best, Alan.
It does sound like the read head from what you've described! It could be component(s) that sense the read though - ie. hybrid or ASIC etc. My bet is on the head though. Regards demagnetizer, yeah - something I worked out 25+ years ago, no one else even tries it, that's why you've not seen it anywhere else lol =D I would suggest cleaning the head with plastx or novus (plastic polish), to get the head surface super clean, and try demagnetising it. The reason demagnetizing can help is if 1 partical from a disk surface somehow gets wedged into the head surface, cleaning may not remove it - and that can influence the field read by the head from that point onward.
Also jam in a new W65C22N6TPG to replace the 6522.
Thank you very much! With your film I could repair my 1541 dirve.
Great =D Glad you got your drive working!
The problem was: wrong connected one cable (with the biggest connector). Thank you wery much :D
P.S. Nice intro
Nice video mate,
I love those type 1541, becase I like the way close the floppy door.
I don't like the way the older 1541 do.
Also do you know that those short board 1541 have a another type of drive rom?
They change it to do that the reading head go to track 0, the older 1541 drive rom and JiffyDOS don't do that.
+MrFixer1983 Yes, apparently you can swap the ROM out on some of these. I think the C revision will take the 1541-II ROM.
I love this guy's work bench. ;-)
Haha, yeah - not good for ESD but good excerise for when you've been sitting at a desk all day. The irony is there's a table right next to where I film - it never gets used for anything lol.
Meh! Static shmatic. That's for anal professionals to worry about, not fun loving geeks. :-D
Oh sweet Graeme my friend needs this...
+Anthony Jordan It's a shame it wasn't a logic based fault, but I've certainly come to realise how sensitive the heads are on the 1541.
+GadgetUK164 You're too clever ;P
Jam in all new caps including new micro 104’s.
Off topic a bit but I wonder what it would be like to align a 1541 drive? I did an Amiga 3.5" drive a few years back "by hand" and it literally took me 4 hours to repeatedly adjust the head position to get it to read/write perfectly across all the tracks. Absolute pain but not the proper way of aligning it I guess lol
+Aron Gooch Yes, I suspect its similar on the 1541 - I mentioned in the video I might have a go at checking the alignment and re-aligning it if required. Just need to find a disk now!
my 1541 works fine but depending on the disk being used i have to lift the casing off and help the disk in. About half way in they get caught on something and i have to put my hand in there and lift the disk. have you encountered this problem?
I haven't come across that but sounds like a simple fix - probably the metal guide that feeds the disk in is a little bit bent perhaps.
I have a C64 1541-II Floppy Disk Drive which I've had for years. It powers up but it won't load anything. Would you be interested in a possible repair?
Maybe later in the year - just now I've got too many other things on the go =D
Could you use a laser rpm meter and shine it onto a disc that is spinning?
+Andrew Littleboy That might be possible, you would need to point it at something that will break the beam once every pass - maybe you could put a tiny piece of insulation tape on the drive spindle underneath, so it acts as a little beam break when it rotates. I've since ordered an alignment disk, so I will see how I get on with that, but to be honest I think its pretty much within spec. I've done a lot more testing this afternoon and everything works fine so far.
Please help my 1541 doesn’t work
Awesome repair job and great vid as always ! ;-)
+Geo Anas Thanks =D Always nice to see your support =D
again a great video. thanks
+Dieter Löffler Thanks =D
If I wanted to fit my C64c with some heat sinks where should I look. Do you have any advice on that?
+The Highlander I use something like this:- www.ebay.co.uk/itm/New-8-Pure-Copper-Memory-Cooler-Heat-Sinks-HeatSink-For-IC-DDR-DDR2-DDR3-RAM-VGA-/350687630950?hash=item51a69c9666:m:mY9NqTBsFmnqyZBVxj1U4xA
I will be ordering some for my 1541 at some point! You need to put 2 or 3 of them in line due to their small size, but they do the job really well!
+GadgetUK164 Oh great stuff! And you attach them with a cooling paste of some sort?
+The Highlander I've ordered a bunch of them. Saw that they come with an adhesive tape.
I just use the thermal adhesive pads on the backs of them. They stick really well normally.
Cool. Thanks for the tip again!
I'll have to get that old Commodore 1541 out of the loft now then ;)
+Nina Evans Get it out and see how its behaving! If the heads and motors are good there's every chance it can be repaired. Let me know how you get on!
+GadgetUK164 It's my boyfriend who does the electronic stuff. I just sit and watch! But he is very much into retro computers (Commodore64, VIC20, Sinclair Spectrum etc). He loves your videos and has cleaned and demagnetized the heads in the 1541, like the machine in your last vid. It now works perfectly, and we can play some of the old games again. Warmest regards and best wishes Wayne and Nina.
+Nina Evans Great stuff =D Glad you got it working! Thanks for watching and commenting - It's always nice to hear that someone picked up something useful from my videos! =D
Error 74....memories !
Sounds like you have the schematics for "1541 late"? Or the service manual is refering to that revision.. You need 1541C (the latest), in that schematic there is no Q4 and Q5 because all of that stuff has been baked into the hybrid circuit I think. Check Ray Carlsens website for the schematics. I had trouble finding it back in May when I repaired mine. I was searching all over the Zimmerman archives, but Ray Carlsen has a good directory strucure. personalpages.tds.net/~rcarlsen/cbm/1541/
+bwack Thanks, it looks like those 2 transistors on mine are for the +5VF. And I think you are right, looks like +12V just goes into the hybrid and +12VF must be internal only to the hybrid. I wonder how reliable those hybrids are. I did wonder what my approach would be if I suspected a fault on there, perhaps there's a way of removing the paint / acrylic coating without damaging it too much. If so it would probably be possible to repair it?!?
Right :) Looked at +5VF yesterday in the "1541C", and compared it to "1541 Late", which does not have hybrid,and there they call that voltage for Vsw instead.. It is only used on analog parts.Most likely to keep the digital switching noise down to a minimum on the power supplied to the parts that condition the small pick-up signal into a digital one. Not sure if you can remove the coating. Maybe acetone bath, but what a smell.. It looks thick.. I wonder why it was coated ? Did they use (package-less) die on board like the blobs you see in calculators ?
+bwack Very interesting! It looks like it has SMD type resistors, caps, transistors on it. I know Kipper2K took one to pieces from the Amiga hybrid. He built his own replacement for that.
Wow. I've heard about Kipper2K and his vampire accellerator. Awesome. This retro scene has some very talented people still developing :) You could take the analog circuits in the earlier 1541 revisions and make a compact hybrid board for the latest 1541. If someone has the time and will do to it.
Yes, there are some really smart people in the Amiga scene! I cannot wait for the Vampire 1200 to arrive. I think the 500 model is next, will probably pick up one of those I think.
Buy a Noctua fan and shove it in there... they are literally noiseless!
I just bookmarked a demagnetizer on amazon...
cant get my floppydrive working
What is it doing, or not doing?
i always get the error ?device not found error
the floppydrives makes the floppysounds when turn on and when the c64 is turned on
My mistake, device not found is usually the 7406 I think.
Or one of the VIAs. There are two 6522's on there, could you try swapping them around (make sure you get pin one in the same position as its marked on the PCB). If the behaviour changes after swapping them around you probably need a new 6522. You can replace those with Rockwell 6522 chips which are readily available on eBay.
GadgetUK164
idk how to remove chips, i tried it with a screwdriver but they didnt moved a bit (maybe a screwdriver isnt enougth for chips lastused in i guess 1990
Love this hybrid gate array :-) unavailable
=D