Fixing a Commodore 1541 Disk Drive

nice and educating video, thx - however I've got some problem with my 1541 (exactly the same type of board as yours). It's not responding to any command - Reset is okay, after starting the spindle is working for a short time - then stops, the stepper is not moving (everything is smooth and clean and easily movable), voltages of course are okay and every TTL is supplied properly. On the scope I see huge data activity on the address-ports of the CPU, clock is fine and clean, the 2 hex-inverters are okay, also the hex-schmitt-trigger (74LS14, bottom left) ..........BUT, what I noticed, the IRQ (inverted) pin #4 on the CPU remains LOW all the time - according to you this is wrong. This IRQ is connected with the pins #21 of UC2 and UC3 - so, what's the bad part here, do you have any idea? Could that be the cause of the not-responding of my 1451? maybe you know? thx

I've been playing along with the drinking game but after 5 shots of de oxit I don't feel so good.

Tants my nemesis! Used a lot in 70’s & 80’s audio equipment, sometimes used for their audio characteristics and low ESR, but used a lot just for their size. I must have changed more Tants "Just in case” than any other componant. Ive obviously canged more eletrolytics but they give away their faults in a more obvious way. Yes a dead tant is in you face but they go from good to bad in micro seconds rather than slowly over time like electrolytic’s. And if a piece of kit you’ve just worked on, goes pop, on a gig or in a studio sesion then say goodbye to your reputation !

My mind is blown. I used to repair these things at a school board. I might of repaired 6 to 10 1541, c64s, 1701 a day. Very fast high volume repair shop. I can still hear the diagnostic audio test playing in my head. Thanks for the memories. Wow. I can't believe all the old hardware that didn't make it to landfill. Imagine a time where computers that never knew what a virus was.

When those particular caps short.... Talk about throwing an explosive temper tantarum. Ha. Ha. Ha.

Definitely had the scope ground leads fail before. On some scopes, you can provide the ground using a banana plug on the scope. It isn’t as accurate as the per channel grounds but it is probably good enough for what you are doing here and makes scoping different parts of the board even easier

The rebel club. Nice shirt you rebel.

Curious that after replacing the 6502 four of the chips including the CPU had matching yellow blobs ;)

At the time, the disk drive was more expensive than the computer itself...

Awwww yeah. That's a dusty drive.

👍👍👍

As a retired EE with 50 years of oscilloscope use I can say that I have had several scope probe ground clips fail. Other test leads as well. Right where the hard rubber for the strain relief ends is common. Grab both the metal ends and you may be able to pull the lead apart and see where the metal failed. It can be very frustrating figuring out what's going on, especially when its not completely broken, just intermittent.

you are a great inspiration, i have reasonable electronic knowledge and just purchased a C64 with disk drive, no PSU and not knowing if any of it works...fingers crossed will be an interesting project

Man these videos take me back to my early computer days. My first machine was a C=128 and I ordered a 1571 and a dataset with the package from Sears (My only credit card!) Later I picked up an old c64 for personal use as I couldn't get access with 2 kids in high school using the 128 all the time. I even had a plus4 when the price on them dropped to 20 bucks. Even went so far as to buy a luggable from a fellow user who went to PC. I sold that several years ago for enough money to buy a new laptop. Now I sort of wish I still had it but there are many things in life that I feel that way about. Thanks for the trip back in time!

two ways that can go bad, because it is so short you put a lot of strain on the wire the jacket will stretch but the wire inside will not and that wire will break. the other way is that the bending of the wire will Break at the weakest point.

So what is the "future project" where he used that drive with?

nice . im impressed.

I have a similar problem with a " Vic" 1541. I'll swap out the CPU and see if that helps. Thanks!

Great videos. Thanks.

It’s crazy how complex floppy drives were! Compare that to a cheap USB floppy drive. Now the host computer does most of the work.

I hope DeoxIT hooks you up. I just ordered a huge can

Still to try fix mine have the alignment disc, it seemed to have formatted a disc so it must be the alignment as everything else worked which hopefully tells me there is nothing wrong with the electronics or mechanics just needs alignment if my hunch is right as it is virtually new externally and internally, one question why not wear an anti static wrist band? that kinda scares me :/

I have a C64 that has a blank screen as well.
But just a side note, Gottlieb pinball machines ran off the 6502 cpu for a long time.

Hi, I have a drive that when I turn it on I get both lights and then red light goes out and no spin, and looking at board the C15 looks like it blew up , kinda like u had one on yours. Could this be the issue ?

Somebody get this guy and IC puller...

Service manual calls it a “Tantalium” capacitor - a typo or did the name change over time?

I don’t know why the 6502 chip would die but i wouldn’t be surprised if the generated heat from the transformer will eventually cause the 6502 chip to die,maybe if we could just put heatsink stickers on those chips to take off excess heat in order to increase their lifespan.

I realize this is an older video, but that drive looks like it had been modded with a parallel connection. SpeedDos had a parallel mode that used that 6522 on the data pins and connected to the the parallel port of the C64. This would not only dramatically speed up the drive, but there were parallel nibbler copy programs that would work on any C64 disk that was not physically altered (some had copy protection that used a physical hole in the disk at specific spots on the disk). That neatly cut out slot in the case looks precisely where a parallel ribbon cable soldered to the 6522 chip would go. Whoever did that mod probably swapped the chip and kept the one that had the ribbon cable connected to it...

Question, can I use a regular 6 pin din cable for a drive cable?

I'm curious if you'd be willing to fix another 1541? I have 2 working ones and a 1571. I replaced the 6502 and a 6522, but still just powers on and spins forever. I used to use it for transferring my old disks to PC but it started acting up several years ago.. I think it might have to do with one of the voltage lines. It's just been sitting on a shelf since. (just checked voltages using the points shown in the video and they look fine)

i have a 1541 drive and the L8 coil inductor or what ever you call it blew and started to smoke, if replaced is that the only issue or could it of damaged anything else, it was working until this L8 blew this is a different drive from the other post i commented on. please help or anyone that reads this

Adrian what about static damage? on every video you just touch the legs of the ic's it just feels weird the cia's on my amiga died by looking thev wrong way at them let alone touching them the wrong way. Do you have an ancle band attached to ground or some thing? Ciz i never see you wear a wristband.

The vicII2 DOES fit with a SIDFX on a 250407 - spread the news!

Great work. I suspect that the shorted cap may have damaged the 6502 chip.

Love your videos! After no success with the pi1541 and the sd2iec troubles with fastloaders i'm extremely tempted by a real 1541

how do I get in touch with you? I have 2 1541 disk drives that power on but do not send a signal to the pc. I would like to talk to you about this problem

4 years later this video is still valuable! That tidbit about the 74123 can interfere with reading disks might be what I needed to hear. Thanks Adrian!

I often see that when people mention performing repairs on old 1541's they replace old IC chips with spares from other units. Is it risky to just buy new equivalent chips from an electronics store or aliexpress? Using brand new chips seems cheaper. Thanks a bunch.

great job of logically going through the troubleshooting process...you're a pro!

+++🐸🦘+++OH+++II 🦜 REMEMBER ❓❓❓ HAVING A 1541 DISK DRIVE 🛃 IN 1983 + IT WORKED FINE 🤣+++ IT WAS A GEAT ACCCESS THAT WENT WITH MY COMMODORE 64 🤩 + IT GAVE ME 🐸 GREAT SATIFACTION 😍++++++🥰 LOVED IT+++

I have 2 old 1541 drives coming my way, so watching this gives me some help at know what to look for. Thanks.

Today, July 25, my 1541c was working, the red light went off, and when I plug it in again it doesn't stop spinning and the red light stays on 😞😞 could it be 6502???? I don't see a short circuit or anything burned

Tantalum is polarized.

I had that exact drive model from 1986 to like 1989. That noise you‘re complaining about was there from the first day to the day the drive broke. It was never an issue.

So on fast tracking, it's normally the likely culprit to be the 6502 IC if not the caps. i'm about to start the rolling ball on 3 of my own original 1541's at work with Adrian Franulovic hoping i am able to have ready a spare drive just in case the trusty spring, say, were to accidently fall into the water and lose it's pushing power. i'll be taking one home afterwards for creating a physical disk that will be used for my WiFi modem containing CCGMS. i may find something random and fun from my collection of C64 roms to add as a bonus game onto that disk btw if i know how to make it boot CCGMS by default.

Awesome to see that drive running!! Great work! I did all my most involved 1541 troubleshooting on it when I got it. I powered it on several times AND I tried 2 different disks! :-) Then I put it on the shelf. ;-) Considering where that stuff came from, I am impressed you are getting these running! Great work as always!!!