SE HD issue?

[clh333]

Yesterday I tried to boot a recently-acquired SE Mac and am experiencing what I believe is a hard drive issue:  Similar to the description on http://www.ccadams.org/se/boot.html, the machine has an internal HD but will not boot from it; I can boot from a floppy (OS 6.0.8) to a desktop but the HD is not represented as an icon and the noise from the HD is practically non-existent.  Even though booted to a desktop the drive light flashes continually: 4 or five fast blinks followed by three slow, repeatedly. 

I'm pretty sure these flashes mean something but I can't find a reference.  If I had to guess I would suspect stiction of the head on the platter.  I would appreciate hearing from someone who has seen this, or even better, fixed it.

Thanks for your reply.

-CH-

 

[Johnnya101]

Does it mount with disk utlity/disk format utilities?

If not, something up with it and you can either replace it or try and fix it.

 

[Bolle]

This does sound like you have a Miniscribe drive.

I could never get one of those to work ever again once they failed.

If it is a Miniscribe drive the following error codes apply:

Zero                  = 0.5 second flashing mode
One                   = 0.5 second continuous ON mode
Between Bits          = 0.3 second Off
Between Repeat Cycles = 1.0 second Off

Listed Below are the binary to hexadecimal conversion values:


0 = 0000 4 = 0100 8 = 1000 C = 1100
1 = 0001 5 = 0101 9 = 1001 D = 1101
2 = 0010 6 = 0110 A = 1010 E = 1110
3 = 0011 7 = 0111 B = 1011 F = 1111


Message Definitions
-------------------
Code 0 - Microprocessor RAM error
Code 1 - Microprocessor ROM checksum error
Code 2 - Interface chip diagnostic failure
Code 3 - Write Fault latch will not reset
Code 4 - Index pulse not detected during spinup
Code 5 - Unable to reach 3600 rpm in 600 revs.
Code 6 - Unable to stabilize spin speed in 10 seconds
Code 7 - Unable to maintain spin speed to 0.5%
Code 8 - Unable to uncover Track Zero sensor
Code 9 - Unable to cover Track Zero sensor
Code A - Track Zero interrupter misadjusted
Code B - Shipping zone error, crash stop misadjusted
Code C - Carriage stuck during recal error
Code D - Seek errror during burn-in or recal
Code E - No hall transitions during spin-up
Code F - Unexpected interrupt from processor

 

[clh333]

Thank you both for your replies.  After a little more investigation I can report the following:

The LED blink pattern is apparently 00000111.  There is indeed a one-second delay between repeats but the fast flashes are much faster than 0.5 seconds and the space between much smaller than 0.3 seconds.  It's definitely a code but does not seem to correspond to the Miniscribe table above. 

I connected a (known good) SCSI ZIP 100 drive to the machine, which the machine recognizes and communicates with.  I believe this eliminates the SCSI controller chip as the possible source of the problem.

From the ZIP drive I was able to run LaCie Silverlining 5.x and interrogate the SCSI bus.  At ID #6 is the ZIP and at ID #0 is a Cirrus 20.  Silverlining reports it is unable to reliably access the disk.  Short test series reported no errors with memory access but hundreds of errors on seek and read tests.

Larry Pina's The Dead Mac Scrolls, Ch. 5, P. 281, suggests the ROM chip may be the source of the problem.

Possibly a cable / connector problem but my hunch is still a stuck drive.  Either way the board is coming out; the battery appears to be dead as well.

I'll let you know what I find.

Thanks again,

-CH-

 

[clh333]

Opened the case and took out the drives.  The HD in question is a Miniscribe 8425 SA.  I attached the drive to an Adaptec 2940 UW SCSI PCI card in a PC running Linux (Fedora 28), using power from the PC.  The Adaptec controller did not recognize the drive in the SCSI chain and Linux could not mount it.  I did not hear any nose from the drive although the on-board PCB's Adaptec chip got warm.

When I removed the drive from the Mac I was dismayed to see the board power connector come off the board with the power pigtail.  (You can see it in the attached photo.)  I also made an attempt to get the drive freed by banging it on its end and by turning the positioning armature.  Using an external power supply and no controller, the 8425 did not move on power-up.  Time to fit a replacement.

While the logic board was out I replaced the hard-wired VARTA battery with a tray and a new 3.6 battery.  I will also re-solder the connector before reassembly.  Should I also replace the 16V 4700 uF electrolytic capacitor that is near the flyback transformer?  I've read that this is undersized and prone to failure.  If I replace it, what's a better choice?