larry@sgistl.SGI.COM (Larry Autry) (07/26/88)
Recently, I read on Usenet, about a problem concerning a 1541 that could read
standard 1541 disks, but not copy-protected disks. The article mentioned a
specific chip to replace. A friend of mine has the same problem. Please
e-mail to me (or post) the solution because the article has expired and I need
the information.
--
Larry Autry
larry@sgistl.sgi.com
or
{ucbvax,sun,ames,pyramid,decwrl}!sgi!sgistl!larrysimon@ms.uky.edu (G. Simon Gales) (05/30/89)
The 1541 I gave my sister has died. When powered up, the drive spins,
the red error light comes on (not flashing), and it just sits there. The
motor keeps spinning, the light stays lit.
I have isolated the problem to be on the main logic board; the 6502 and
the two 6522's are working ok. I swapped things around with a working
1541 to figure this out.
The logic board says:
PCB NO 1540050 COPYRIGHT 1982
REV C W-1894MB MADE IN JAPAN 404E
I would appreciate any pointers/ideas for fixing the beastie...
--
/------------------------------------------------------------------------\
Simon Gales@University of Ky
{rutgers, uunet}!ukma!simon - simon@ms.uky.edu - simon@UKMA.BITNETjgreco@csd4.milw.wisc.edu (Joe Greco) (05/31/89)
In comp.sys.cbm article <11793@s.ms.uky.edu>, simon@ms.uky.edu (G. Simon Gales) wrote: ]The 1541 I gave my sister has died. When powered up, the drive spins, ]the red error light comes on (not flashing), and it just sits there. The ]motor keeps spinning, the light stays lit. ] ]I have isolated the problem to be on the main logic board; the 6502 and ]the two 6522's are working ok. I swapped things around with a working ]1541 to figure this out. ] ]The logic board says: ] PCB NO 1540050 COPYRIGHT 1982 ] REV C W-1894MB MADE IN JAPAN 404E ] Definitely a logic board problem. I would suggest that you start off by checking voltages. Compare regulator and rectifier output readings with a functional 1541. MY next step, failing that, would be to check the ROM's. Commodore in their infinite wisdom placed one of the ROM's right next to the heat sink of one of the regulators (that may have changed in later revisions, I HOPE!) and several of my ROM's have literally fried to death. If this is the case, burn an EPROM and pop a fan on the darn drive, as it will more than likely happen again. CPU works? PIA's work? Start checking the other logic. Swap other chips. Static RAM and all. If all of those check out, you are in serious trouble. Unless you are seriously into electronics, I suggest taking it to the shop. (if you ARE into electronics, start checking to see what happens on the various busses and control signals, since the symptoms indicate that the CPU isn't getting very far into the reset routine). Frustrated? Try a sledge hammer. It's been known to work. ;-) And remember, anything you do is at your own risk.... -- jgreco@csd4.milw.wisc.edu Joe Greco at FidoNet 1:154/200 USnail: 9905 W Montana Ave PunterNet Node 30 or 31 West Allis, WI 53227-3329 "These aren't anybody's opinions." Voice: 414/321-6184 Data: 414/321-9287 (Happy Hacker's BBS)
carus@cbnewsc.ATT.COM (bryce.w.carus) (05/31/89)
> In comp.sys.cbm article <11793@s.ms.uky.edu>, simon@ms.uky.edu (G. Simon Gales) wrote: > ]The 1541 I gave my sister has died. When powered up, the drive spins, > ]the red error light comes on (not flashing), and it just sits there. The > ]motor keeps spinning, the light stays lit....etc....etc. > In article <2700@csd4.milw.wisc.edu>, jgreco@csd4.milw.wisc.edu (Joe Greco) writes: > Definitely a logic board problem. I would suggest that you start off > by checking voltages. Compare regulator and rectifier output readings > with a functional 1541....etc....etc. The symptom Simon Gales wrote of is exactly what happened to two of my units. The last one just a few weeks ago, the first one several years ago. I have several spares so I haven't gotten around to fixing the last failure. The first was fixed with a capacitor replacement in the speed control section. Unfortunately, I'm at work and my notes on this are at home. My recollection was the little pup was tied to the speed control chip (a Sony tape recorder component) as part of the closed loop feedback circuit. This was an older ALPS unit where the speed control was on a small daughter board. I'll look up my notes tonight but the purpose of posting such a sketchy diagnosis was to help focus on the likely problem area and avoid being sidetracked. Hope this helps. I'll follow up later...
RYAN-S@osu-20.ircc.ohio-state.edu (stephen) (03/22/90)
Symptom: when the disk drive is powered up, the red light comes on
and the motor spins, and the red light stays on and the
motor keeps spinning. I can OPEN 15,8,15 but any attempt
to PRINT#15 or CLOSE 15 causes the computer to lock up.
Any ideas as to what the problem might be?
Thanks,
Stevefred@cbmvax.commodore.com (Fred Bowen) (03/28/90)
In article <12575494799039@osu-20.ircc.ohio-state.edu> stephen writes: > Symptom: when the disk drive is powered up, the red light comes on > and the motor spins, and the red light stays on and the > motor keeps spinning. I can OPEN 15,8,15 but any attempt > to PRINT#15 or CLOSE 15 causes the computer to lock up. Commodore drives perform a diagnostic when the are turned on. If anything fails, the diagnostic causes the LED to blink a particular pattern which indicates what is wrong. See if your drive is doing this. If not, the ROM is probably bad and the diagnostic cannot be run. Make sure the ROM has not popped out of its socket. Turn the drive off and gently press down on the various socketed chips, and try it again. -- Fred Bowen uucp: {uunet|rutgers|pyramid}!cbmvax!fred domain: fred@cbmvax.commodore.com tele: 215 431-9100 Commodore Electronics, Ltd., 1200 Wilson Drive, West Chester, PA, 19380