The easiest way to recover from the head being positioned above usable track range is to issue an explicit initialization command "I". But I wouldn't expect this to be the case here. Judging by the symptoms (system hanging when the communication is about to happen rather than drive trying to move the head a few times and returning an error) I'd rather expect one of the return lines being fried. What I'd do would be to tap on the lines with a scope or LA and check what's happening there. Both before and after the 06 inverter. This should lead me to the suspect (which probably is one of the mentioned ICs anyway). But I am not sure if the OP has the required equipment at hand. On 20 April 2014 06:30:33 CEST, William Levak <wlevak@SDF.ORG> wrote: > > >Sometimes on these drives, if the head is too far out, when you reset >the >drive, it does not find the directory, and therefore cannot read a >file. > >There are only two ways to fix this: > > 1) issue a block read command to track 1. > 2) open up the drive and physically move the head all the way in. > >This is worth doing before attempting electrical repairs. > >On Sat, 19 Apr 2014, Ville Laustela wrote: > >> >> Hello! >> >> I found out that I own two Commodore 1541-II disk drives, both in a >non-working state. >> >> Testing with a measured-good PSU, I got the following results with >both drives: >> >> - power on: normal activity (power led on, spindle runs and drive led >lights for few seconds, then stop) >> - connected to a C64: drive resets with the computer normally >> - attempting to load halts at "SEARCHING FOR": drive spins (with leds >on) but the stepper doesn't move. Only way out is to reset the >computer. >> >> By the Ray Carlsen's website >(http://personalpages.tds.net/~rcarlsen/cbm/1541/1541-II/1541-II.txt) >these symptoms point to either U7 logic chip (7406) or U6 VIA (6522). >On one of the two drives I replaced the U7 chip but that had no effect. >> >> Before I start a (lenghty, painful, boring...) removal of the 6522 >VIA, I would like to ask here if anyone would have any other ideas? >> >> Cheers, >> Ville >> >> >> Message was sent through the cbm-hackers mailing list >> >> > >wlevak@sdf.lonestar.org >SDF Public Access UNIX System - http://sdf.lonestar.org > > Message was sent through the cbm-hackers mailing list -- Sent from mobile phone (so please have understanding). Message was sent through the cbm-hackers mailing listReceived on 2014-04-20 09:00:03
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