Posted By
rockdemon
on 2007-07-01
12:54:36
|  1551 - alignment?
Just got a 1551, but when i ty and get it to read a disk the head sounds like it's hitting the stops. anybody know how to align the heads on a 1551?
Thanks,
Rich.
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Posted By
SVS
on 2007-07-01
14:11:14
 | Re: 1551 - alignment?
Hi,
first of all you could try to unlock the head, by command "I".
Syntax is:
OPEN 15,8,15,"I0" (string is I and a zero) [Return]
After a while, when (and if) the red light turns off:
? DS$
you should obtain "0,OK,0,0"
then retry to read the disk and keep us informed 
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Posted By
JamesC
on 2007-07-02
00:37:32
| Re: 1551 - alignment?
The 1551 drive itself (but not the controlller card) is almost identical to the 1541. You can follow the instructions found here:
http://home.comcast.net/~safeharborbay/tcr/cbm/1541.html
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Posted By
TLC
on 2007-07-02
12:25:48
| Re: 1551 - alignment?
The 1551 is (mechanically) a 1541C derivative; these rarely, if ever go out of alignment. After trying to initialize the drive (see SVSs post) you might want to read these procedures here: http://staff.washington.edu/rrcc/cbm/1541-II.txt You probably don't need all but the chapter dealing with the mechanics.
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Posted By
rockdemon
on 2007-07-27
09:23:18
| Re: 1551 - alignment?
thanks
theres a good few things for me to try there :o)
Been on hols - so sorry for the slackness replying.
Rich.
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Posted By
SVS
on 2007-07-27
10:51:49
| Re: 1551 - alignment?
Advanced procedure:
Once open the drive, run the utility Floppy-Einstellhilfe. Now, with a plastic screwdriver you can set the screw in order to obtain the better (shorter) time (output by utility on screen) that with a 1551 is about 9. This means that you have phisically aligned the head and made as fast as possible the reading.
Do not set a value too much low (8 or less for the 1551) because you could be nomore able to read next disk (you should need a second running unit in order to load the utility to restore a good speed).
At last, check some fastloader if still continue to work. If not stepup the value (9 -> 9,2 for example).
The same procedure works on a 1541x but the optimal value is greater (10).
Hope have helped.
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Posted By
rockdemon
on 2007-07-30
16:09:36
| Re: 1551 - alignment?
Thanks.
I'll try this - it'll be saturday now ( busy week this week :o))
Got to get it running
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Posted By
TLC
on 2007-08-01
12:00:55
| Re: 1551 - alignment?
Argh. I'm actually, err, amazed (or something else). ...I may be talking out of pure ignorance, but would you someone please tell me the common point of the drive's speed of rotation and the alignment of the read/write head?
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Posted By
JamesC
on 2007-08-01
18:54:28
| Re: 1551 - alignment?
I suspect that SVS meant "Additional procedure" instead of "Advanced procedure". If I had my 1551 apart to align it, I might as well optimize the speed while it's already disassembled.
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Posted By
SVS
on 2007-08-02
02:28:34
| Re: 1551 - alignment?
The two arguments are linked. In fact the fastest speed is achievable only with best aligned head.
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Posted By
rockdemon
on 2007-09-04
10:07:49
| Re: 1551 - alignment?
The command OPEN 15,8,15,"I0" produces a read error when i use ? DS$
Does this mean it could be a simple case of cleaning the head? The trouble shooting guide linked to by TLC seems to be in order in terms of lights and what the motors are doing.
(I assume i need to do this before trying anything with better aligning the heads?
THanks in advance,
Rich.
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Posted By
TLC
on 2007-09-08
07:01:53
| Re: 1551 - alignment?
Yes, presumably.
Nowadays, I mostly use a 1541-II, and I get similar symptoms that you described rather frequently. The solution is usually as simple as taking the drive apart and cleaning the head. Some carefulness is advised, but otherwise, it's not that complicated. The dust is usually also clearly visible on the head. You can use cotton buds with ethyl- or isopropyl-alcohol.
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Posted By
rockdemon
on 2007-09-08
10:55:16
| Re: 1551 - alignment?
Great - i'll go to maplin in the morning, get some proper head cleaner:o)
Cheers,
Rich.
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Posted By
rockdemon
on 2007-09-12
04:59:23
| Re: 1551 - alignment?
Well cleaning the head didn't help, so i think the head must be so far out of alignment that it can't read anything.
Does this make sense? Should i try playing with the alignment first, or is there likely to be something else up?
I do also have a 1541C. Is it worth attempting to plug the 1541C mechanism into the electronics from the 1551, to see if it's an electronics fault, or would that risk too much damage to the working drive?
It looks like someone else has struggled with this drive as the inside seems to be immaculately clean - not a state i'd expect a 20 year old piece of hardware to be in....
Sorry to draw this out - i just don't want to break anything irrepairably.
Thanks,
Rich.
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Posted By
TLC
on 2007-09-14
01:52:34
| Re: 1551 - alignment?
You can know if the drive really has alignment problems, if you try formatting and reading a disk.
If it's an alignment problem, it will work with disks formatted by itself (as, for those, the alignment is still "perfect"), and refuses to read disks formatted by other drives.
If it'd turn out that it even refuses to format a disk, it's most probably not an alignment problem. In that case, although I never tried this myself, as far as I know, it's possible to replace the drive of the 1551 by one of a 1541C... so you can make a test.
You won't break anything, as I guess. The 1551 is mechanically a 1541C derivative, and most of them were even assembled with the same "turn-down" type lever drive (from Newtronics). You'll see... If you find similar connectors on them, from that on, I doubt that you could hurt anything (...and if they didn't match, you won't exchange the drive mechanics anyway). One thing to make sure, the orientation of the cable connectors when connected to the board (as these have no notch or similar that make it impossible to connect them oppositely... just check and make notes of which pin of the connectors go to pin 1 of the connectors on the mainboard, plus some attention, that's probably enough).
Good luck!
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Posted By
rockdemon
on 2007-09-14
03:53:58
| Re: 1551 - alignment?
thanks - i'll try this.
It won't even format or read disks which it has tried to write.... so i guess this is the best path...
Thanks a lot for the support :o)
Rich.
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Posted By
Solder
on 2007-09-14
07:39:08
| Re: 1551 - alignment?
A lot of 1551 drive has the problem of a defect head. I'm not sure, but I think there are 3 coils in the head with a resistor around 16 Ohm. You can measure this resistor and if it is very higher the head is defect. (Details I have to check at home, sorry). Please deconnect the head-connector from floppy's PCB while measure.
I don't know what's the reason for this defect. Sometimes floppies that wasn't used a long time have this fault. So I think it can be a chemical problem in the head which destroyed the coil.
Solder
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Posted By
rockdemon
on 2007-09-14
10:31:08
| Re: 1551 - alignment?
Thanks - I have a meter so i''ll check this too when i get home...
Thanks,
Rich.
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Posted By
SVS
on 2007-09-14
14:24:41
| Re: 1551 - alignment?
Just to let you know. A few years ago I've inserted a 1541 mechanism into my 1551 with defected head (see previous Solder' post). All works as well, only the external door is beige instead of black 
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Posted By
roxkdemon
on 2007-09-14
14:44:55
| Re: 1551 - alignment?
@SVS brilliant :o)
I can see me getting another 1541 off ebay very shortly ;o)
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Posted By
rockdemon
on 2007-09-15
14:15:42
| Re: 1551 - alignment?
Well the head reads at 66 megaohms so i guess that's toast...
Thanks for all your help guys. when i have a second 1541 to butcher i'll be back :o)
If you're ever in leicester let me know - it'll be beer for you :o)
Cheers,
Rich.
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