First post, by ziper
Hello,
I am attempting to repair a scanning electron microscope made by a now-defunct company called Tracor-Northern, mid 80s vintage. It has not been used in at least a decade. I believe all the microscope hardware should be functioning. The computer hardware and software, however, is rather questionable. I don't know how much damage may have been caused before it was mothballed, by my repair efforts, or simply by age. If the computer half of the system is beyond repair, it is possible to reuse the microscope hardware with a new control system. The cost for such a refit starts at least $50,000. (And, of course, it is much more satisfying to get the original stuff working).
I have no documentation whatsoever on the machine. I can only hope there is a digital copy somewhere that can be recovered from what I have.
I made a very foolish error already by connecting a ground wire to the 5v rail. (In my defense, it was the same color as the +5v wiring, but I still should've rung it out). A jumper on the back of the hard drive smoked. I have no idea how much current was shunted or how much may have been going around damaging things.
The computer does not POST. It gives a beep code (that I have no idea the meaning of) and turns on the displays, but does not display anything. I am now trying to use a blueSCSI to clone the HD or any of the 3 tapes that I think have copies of the OS. Hopefully, I can run that software on the blueSCSI to get the computer to POST or at least get some documentation. (Yes, I probably should've done this before trying to power the machine.)
So, the hard drive: made in 1987 by Magnetic Peripherals, Inc. MN 94171-307, PN 77777009, no marked capacity, 50 pin SCSI connector. Besides the previously mentioned smoked jumper, no visible damage on any of the boards. When powered on, the spindle twitches, but does not spin up. It is free to move by hand, so probably not a friction issue. blueSCSI reports "NOT_READY, running STARTSTOPUNIT", so the board is able to communicate at least somewhat. A handful of similar (but not identical) SCSI drives are available on ebay. If the issue is the spindle motor controller, I could replace that IC from a donor board, but I'm not sure if that is the issue or even which chip is the controller. Am I correct in assuming that swapping over the whole PCB assembly would not work? (I know newer drives you can't do this, but maybe these drives are primitive enough that you could get away with that).
Or, the tapes. They are QIC-120, 3M DC 6150. They show the usual tape issues of the tensioning band being totally toast, but I have replacement bands and they seem to have been parked in the no data section, so I think the data should be recoverable. Theoretically, assuming the computer works, I could get an image from one of them and do a fresh install on on a blank blueSCSI, right? The drive powers up and tries to work, but instead of advancing the tape the stepper motor on the bottom left just twitches, and blueSCSI reports "START STOP UNIT on target 1 failed, sense key 0x04". Is there any reason I can't use a relatively easy to get, somewhat more modern SCSI tape drive to get the data off the tapes?
Thank you in advance for any advice, guidance, or criticism.
Pictures of the hard drive and tape drive attached, as well as the computer cabinet and a random board.
