Do you mean it can't read _any_ track or that it can't read the _specific_ track that it thinks it is looking for? -----Original Message----- From: firstname.lastname@example.org [mailto:email@example.com] On Behalf Of William Levak Sent: Friday, July 06, 2012 1:29 PM To: firstname.lastname@example.org Cc: email@example.com Subject: Re: Re: 1541C troubles It's not a problem of alignment. It's a problem of programming logic. The drive occasionly gets in a state that the programmers did not anticipate. The head moves, but does not do anything, because it cannot find the track it is supposed to be on. The fix is to step the head all the way out and then back in again. The test routine does this. You could also do this by issuing the commands to read track 35 and then track 0. A calibrated disk is not necessary, you only need a disk with the track and sector headers written correctly. Moving the head by hand sometimes works, but the test routine is more reliable. On Fri, 6 Jul 2012, firstname.lastname@example.org wrote: > William, > > This 1541C has not a problem to move the head and even if it's misaligned (it could not misalign that much in a minute or so) it should be able to format a simple floppy and read it back - To me, the problem is "somewhere" in read/write logic but I don't know where to start searching on this board revision. > > > > Regards > > Tous vos emails en 1 clic avec l'application SFR Mail sur iPhone et Android - En savoir plus. > > > ======================================== > > Message du : 06/07/2012 07:18 > De : "William Levak " <wlevak@SDF.ORG> A : email@example.com > Copie à : firstname.lastname@example.org Sujet : Re: 1541C troubles > > > > > If 1541 drives crash while the head is too far out, they cannot find > their way back to the home position. > > Use the drive test routine on the demo disk to reset it. You will have > to load the test routine from another drive unit, and run it. It steps > the head all the way out and back in again. If this doesn't fix it, > you have a real hardware problem. > > On Thu, 5 Jul 2012, email@example.com wrote: > >> Hi, Friends >> >> >> >> I am in trouble with a recently acquired 1541C (white 1541 case, white newtronics mecanic) and I need your lights ! >> >> My first remark when it arrived was that the fuse support was damaged and metal body support slightly blend. Except from this, noting noticeable and it was operating surprisely well. >> >> After few days of use it bruptaly crashed (in software I mean ...) while running a very recent C64 demo. Power cycled eveverything and thought all will continue to go allright for next dozen of years - but no ! >> >> The drive work absolutely normally in apearance but is completely unable to read or write anything at all. Spîn motor works okay, stepper is also okay, IEEE communication is okay but it's impossible to read or even format any floppy disk. >> >> I've done all easy things - cleanned the head with isopropyl alcool, reseated all connectors, swapped both 6522, checked 12V and 5V but no change, it still won't read/format anything. I've searched the web for a situable service manual/schematics and found that my MainBoard is labelled 251854, what seems to be PCB#250448. I don't have any spare Mitsumi/Newtronics mecanic to swap so I can't determine if mecanics is definitely okay or not. >> >> The board has an hybrid UD1 as -02 a ROM UA2 as -01 and a gate array UC4 as -01 - This seems to be a very standard board. >> >> I've tested head's wire continuity that is okay for all wires but I can't find any reference for expected values - I've values for ALPS for pin 1-5 that should be 32 ohms - I'm currently at 24 ohms. If I take pin 1-3 or pin 3-5, I have 12 ohms, so, what seems to be coherent. >> >> Can anyone confirm value of 24 ohms for a good head in newtronics mecanic ? >> >> Does anyone have a better idea than removing the shield soldered under the PCB and reheat all points around UD1/UC4/UC5 plus all discrete components involved around ? >> >> >> >> Regards - Thanks for your help >> > > firstname.lastname@example.org > SDF Public Access UNIX System - http://sdf.lonestar.org > email@example.com SDF Public Access UNIX System - http://sdf.lonestar.org Message was sent through the cbm-hackers mailing listReceived on 2012-07-07 02:00:27
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