augenbra@MICRO.UDEL.EDU (06/10/86)
I've been having trouble with my ST disk drive recently. The problem is that it would read fine, but cause the system to lock up anytime a write is tried. The system boots up and reads disks (and writes to the ram disk) fine, but if I try to write to a disk, the drive activity light lights up, the drive spins, and then the screen goes white. I must then reset the system to get things going again. The system seems to actually write one sector (if I try to create or rename a file, the system will crash, but the creation or renaming will be there on the disk next time that I bring the system up.) I have the following configuration: 520ST with 1Meg memory upgrade with 68 ohm resistors 1 Single sided disk drive Color monitor TOS on disk Older brick power supply with one cord coming from each end Checking the power supplies has revealed the following: Voltages coming to the disk drive are fine +/-12 Volt supplies to system unit are fine +5 volt supply to system unit is +5.33 Volts under load I do not have easy access to someone else's 520ST system to try different pieces in (they don't seem to be real popular here). My question is if anyone has any suggestion of what to do. Specifically, could a 5V supply supplying 5.33 cause a problem (I realize that 7400 series IC's are rated only to 5.25, but the rest of the system is working, after all). Is there maybe an RC circuit in the floppy controller that is real sensitive to voltage variations? Or is it maybe just a dirty disk drive ? Any ideas on things to try would be appreciated. Also, does anybody know what Atari does if someone tries to send a 1Meg upgrade 520St for warranty repair work. Do they fix it under warranty, fix it but charge you, or refuse to even look at it? Any help would be appreciated. Joe Augenbraun "Let's go commit those crimes!" "Ya, yah, let's get Sushi and not pay" - from the movie _Repoman_
wampler@unmvax.UUCP (Bruce Wampler) (06/19/86)
> > I've been having trouble with my ST disk drive recently. The problem > is that it would read fine, but cause the system to lock up anytime a write is > tried. The system boots up and reads disks (and writes to the ram disk) fine, > but if I try to write to a disk, the drive activity light lights up, the drive > spins, and then the screen goes white. I had exactly the same problem - mine was caused by bad seating of the big square custom chips - the graphics chip and the mmu. I've noticed that Atari is now using clips on these chips carriers. My earlier machine had no chips. Try to be sure those chips are well seated in their carriers.