On 8/22/2015 12:55 PM, Tapley, Mark wrote: > Jay, > this is a really great post. I feel really bad for you - having the > same piece of equipment go bang/flash more than once would have been totally > demoralizing to me - but I really admire both your tenacity and your > willingness to share this with the rest of us. > Thank you! Sure hope that disk is spinning its proper string of bits > before long. You deserve the chance to post a victory story soon! > > - Mark >
Thanks. Really, such mistakes aren't too demoralizing if one can get the parts, get them in a reasonable amount of time, at a reasonable price, and have the skill to do the fix (which, in this case, wasn't a whole lot) -- especially if there are good lessons to be learned along the way. But the carelessness was DANGEROUS, which is really why I posted it. (BTW, in the way of other stories, a good friend once took out the processor UNIBUS interface and damaged peripherals when his watch shorted to the backplane of a PDP-11/20. I also did something not too dissimilar with my ring shorting out one bus line on my PDP-8/L. Sigh). Unfortunately, bearings did not help the floppy drive, so now I am busy taking the floppy power supply I got with my FD 100-8, making sure it is up to spec to use with the Shugart (and correcting that if needs be), and making it safer (mains fuse, switch) and more fault tolerant (fuse in the 24V line, at least) and making sure all of the mains connected innards are not exposed. Just about done with that. The +24V and -7 to -16V are in spec, but the +5V (which, curiously for a 1A supply, does NOT use a simple 3 terminal regulator) is a tad high, at 5.35V. I may just change it to use a three terminal unit. Once I get that together, I can try out my SA-801's to see if that was what blew the Altos power supply up, or if it just shorted against something when I started that test. I can also more easily then measure the "wobble" on the SA-800 and compare it to other drives, swap out spindles, etc. JRJ
