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1541 - restored!
https://mail.retrohackers.org/viewtopic.php?f=20&t=381		 Page 1 of 1
Author:  lodger [ Tue May 13, 2008 8:42 pm ]
Post subject:  1541 - restored!
Well, it all started a few days ago, when I took some time to play around with the GEOS files provided by cbmfiles.com . To build you own GEOS disks, you need a 2nd drive to get the job done. And for GEOS a 2nd drive is also mandatory.

So I got myself another 1541 drive on ebay and it arrived two days ago. Since then, I've tried everything to get the damn thing back to work again: it can read files, but writing data to disk or formatting it results in a "21 read error", with the drive led blinking. After reading an article by Ray Carlsen, the guy with the very good artivles on how to fix certain problems with your commodore hardware, I decided to test the 1541 circuit board on my working floppy to find out wether it was the head / mechanics or the circuit. Well, the circuit worked all right with the other drive. So it must be the mechanics. Hmm... what now?

Last chance: there is a program called "1541-tester.prg". It's a BASIC porgram that runs several tests on your drive, including certain alignment and power options I've never herade before. I ran the program, all the tests in it and just followed the "defualt path" of answering "y(es)" everytime the program asked for a positive reuslt of the test. Well, what can I say? The thing *works* !!

I don't know what the porgram did, I even don't know where I got it from. But it did a perfect job on that old 1541! Maybe the drive just appreciated being treated so carefully just to get it back to work, maybe the 8bit gods had a mercy with me, I dunno - but it *works* !!! :D :) :) :) :D

just wanted you to know ...
Author:  Devia [ Tue May 13, 2008 9:41 pm ]
Post subject:  Re: 1541 - restored!
Hehe.. I have a drive that some years back insisted on me doing an open15,8,15,"i:";close15 before it would work.. this was at every power on. At some point it just started to work normally again and have done so ever since.
Some things are not meant to be understood :D
Author:  RaveGuru [ Wed May 14, 2008 5:36 pm ]
Post subject:  Re: 1541 - restored!
Well, 1541 drives sure are dodgy, both the originals and the 1541-II's. Although 1541-II's seem much more prone to errors than the original brick. I have two 1541's and three 1541-II's. All the II's have problems, one is completely out of order.

It's quite interesting. The completely broken 1541-II is actually working except that it's executing all the tasks with about twice the normal speed, including led flashing and head movements (I don't know about rotation speed). The two other II's have the same problem. They can work fine for hours (sometimes weeks) and suddenly they can no longer read anything. It doesn't matter what you throw at them. When they go into failure-mode they refuse to read a single byte correctly. Once in failure-mode they stay like that for an arbitrary amount of time ranging from seconds to days. Suddenly they snap out of it and are working perfectly again, like nothing ever happened :lol: The 1541 and 1541c are both working fine though, provided they are kept cool of course :P
Author:  lodger [ Fri May 16, 2008 4:41 pm ]
Post subject:  Re: 1541 - restored!
RaveGuru wrote:
The two other II's have the same problem. They can work fine for hours (sometimes weeks) and suddenly they can no longer read anything. It doesn't matter what you throw at them. When they go into failure-mode they refuse to read a single byte correctly. Once in failure-mode they stay like that for an arbitrary amount of time ranging from seconds to days. Suddenly they snap out of it and are working perfectly again, like nothing ever happened :lol:


Sounds like a temperature related problem. Try cooling the drives with a fan and look if they work better / longer. The IIs seem to go a bit faster than the older 1541s. Mine is from 1987 (my first one, still got it!) as is my C64 (white wedge. Well, it used to be "white" back then. Is more of "beige" now :wink: ).

Oh, the "new" 1541 i just fixed got misaligned again. I tested the board on my "PC64" (some case modded C64 in a late 80's PC box, see attached pictures). It worked well with the built-in 1541. So it must be the drive mechanics or whatever it is called in english, that is used to pus and pull the drive head :D

Attachments:
File comment: The custom made keyboard boasts to bee manufactured by IBM,Scontland (UK). Sticks very tight to the case. Dosen't look like it's "fake", but who knows?!!
IMG_0886.JPG [1.26 MiB]
Downloaded 76 times
File comment: "PC64" the way I let it "rest" in my rack at home. Whoever built this, made a really cool device.
IMG_0885.JPG [1.49 MiB]
Downloaded 78 times
File comment: "PC64", as I call it with the board of the defunct drive I got from ebay. The electronics work ok with the internal "PC64-1541" ...
IMG_0879.JPG [1.69 MiB]
Downloaded 78 times
Author:  RaveGuru [ Sun May 18, 2008 5:55 pm ]
Post subject:  Re: 1541 - restored!
lodger wrote:
Sounds like a temperature related problem. Try cooling the drives with a fan and look if they work better / longer. The IIs seem to go a bit faster than the older 1541s.

I don't think it's a temperature problem. Sometime's the drive is "broken" on a "cold start" (after being powered off for a long time). Also, sometimes they stay broken for hours (maybe days). I've never had them hooked up together to see if they fail simultaneously though. I suspect something is on the verge of failing in the drives. Guess I should check for hot IC's and have some freeze-spray at hand next time it happens.... Well, In that case it will actually be a temperature problem :D
Author:  lodger [ Tue May 20, 2008 6:29 pm ]
Post subject:  Re: 1541 - restored!
RaveGuru wrote:
I don't think it's a temperature problem. Sometime's the drive is "broken" on a "cold start" (after being powered off for a long time). Also, sometimes they stay broken for hours (maybe days). I've never had them hooked up together to see if they fail simultaneously though. I suspect something is on the verge of failing in the drives. Guess I should check for hot IC's and have some freeze-spray at hand next time it happens.... Well, In that case it will actually be a temperature problem :D


Hmm... I'm not an electronics expert, but this really sounds like an electronics problem. Either the chips get too hot or some transistor or capacitor is slowly dying. The latter option would explain why the drives sometimes do startup "broken".

Heck, I'd give everything for some new 1541 mechanics... stuff, you were thrown with in the early 90s ... *sigh*

Oh, BTW: what's this "JiffyDOS" all about? Came across that a few weeks ago. Never heared of it, even back in the 80s. I do know "DolphinDOS" and CBM DOS though (never needed CBM DOS, still stick to LOAD"$",8:LIST) ...
Author:  MagerValp [ Wed May 21, 2008 8:22 am ]
Post subject:  Re: 1541 - restored!
lodger wrote:
Oh, BTW: what's this "JiffyDOS" all about?


Replacement drive and computer roms, with a floppy speeder and a dos wedge.
Author:  RaveGuru [ Thu May 22, 2008 1:12 pm ]
Post subject:  Re: 1541 - restored!
JiffyDOS is simply fantastic! Just as MV stated it's a ROM replacement (only) for computer and drives, but it's backwards compatible which means you can still use non-JD drives with JD computers and vice-versa. And it really gives huge speed improvements and additional functions such as a DOS wedge and built in file-copy, etc. And I'd say it's compatible with 99.9% of all software. I ran JD in my machines for 15 years and I love(d) it. Works fine with AR6 and other carts too.
Author:  zap [ Fri May 23, 2008 9:25 am ]
Post subject:  Re: 1541 - restored!
RaveGuru wrote:
JiffyDOS is simply fantastic! Just as MV stated it's a ROM replacement (only) for computer and drives, but it's backwards compatible which means you can still use non-JD drives with JD computers and vice-versa. And it really gives huge speed improvements and additional functions such as a DOS wedge and built in file-copy, etc. And I'd say it's compatible with 99.9% of all software. I ran JD in my machines for 15 years and I love(d) it. Works fine with AR6 and other carts too.


On two of my c64 i have not even bothered to install a switch thats how compatible i have found it.

Enjoy :D
Author:  RaveGuru [ Sun May 25, 2008 7:11 pm ]
Post subject:  Re: 1541 - restored!
zap wrote:
On two of my c64 i have not even bothered to install a switch thats how compatible i have found it.

Enjoy :D


Same here :) During the years I've only ran into problems with some occational demo afaik. Most of them were later JD fixed.

JD FTW! :D
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