(last updated: 04-Jul-2017)
The current configuration is in its original 'as acquired' condition.
This unit belongs to the two H-11A system(s).
20-Feb-2006
This unit was part of a large pickup in Longmont, Colorado.
04-Mar-2006
As usual, I first removed surface dust with the shop vacuum, and then cleaned all exterior surfaces using 'baby wipes'. With the exception of a few corners having chipped paint, the condition of the enclosure is surprisingly good. It cleaned up very well, and looks almost new.
There are a group of four 1/4" holes in the top cover, in a canted but regular square pattern, almost as if it were a mounting position for a fan. But I can't guess what they are for; there is no central hole for a fan.
There are a couple of things that need to be fixed. First, the connecting ribbon cable to the CPU has been snipped off close. Obviously, someone was in a hurry to move this system, and didn't bother to open the bottom and detach the cable properly. So a new end will have to be made for the cable (the other portion of which is currently in an H11 CPU connected to the controller). The second is that I was unable to close the door to drive 1. Somehow it was jammed and will require attention.
I removed the top and bottom covers. I vacuumed the power supply and controller PCBs. The short end of the connecting ribbon cable attached to the controller here, and I left it connected, but pulled the loose end into the enclosure. Also, I did a light vacuuming of the drives themselves, but there really wasn't much dust in the first place.
Deciding to try correcting the balky door to drive 1, I removed the drive itself from the whole assembly. I removed the four screws in the tray under the PCBs to release the drive, and after disconnecting the power and data cables, I lifted it free. When doing so, a small screwed dropped to the table. I had noticed that there was one of two screws missing that hold the door pawl to the door arm. This was an obvious match and I replace the screw into the pawl. As it turned out, the door was jammed because the arm was binding on the drive chassis. I figure this was due to a hard knock that pushed the door handle inward, and it shifted on its mounts, thus binding. The door is designed to be adjustable, so simply by loosening the door mounting screws a little bit, the door came forward easily. I adjusted its position to match that of the other drive, and that solved the problem! The door now operates just fine.
Since I had the system so far disassembled already, I decided to pull the other drive, too, and just make sure that everything was cleaned, and in good order. One of drive 0's four mounting screws is missing. Also a short countersund screw is missing from one of the PCB's hinges. I vacuumed and cleaned all surfaces.
I manually turned the spindle motors of each drive and the belt kind of 'peeled' away from the spindle pulley. The belts actually look in good shape, and have good grip and tension, but they have clearly been in one place for a long time. This also tells me that I need to be cautious as I power the system. The power supply may need to have its capacitors reformed properly, so I'm not planning to power the system, until I have the means to take care of the cap reformation properly.
I reassembled the system and attached all power cables. I also tightend all four transformer mounting nuts on the back panel. All four were loose.
04-Apr-2006
Preparing for capacitor reformation, I have to get at the gigantic capacitor in the power supply. I removed the top cover's 9 screws and removed the cover. Holding the capacitor housing are 2 screws on the rear panel, and 1 inside, on a flange on the front of the housing. I removed all three screws.
The capacitor assembly has three sets of wires connected, each with a quick disconnect fitting. One goes to the transformer, another goes to the rear of Drive 0, and the last goes to the drive mounting tray. I disconnected each and removed the capacitor assembly.
I removed the terminals from the capacitor, and had to relief the tension in its securing bands so that I could read the ratings. It is a 39,000uF 40V capacitor. Seems pretty big to be only 39,000uF. Anyway, here we go.
07-Apr-2006
I reconnected the wires to the capaicitor terminals and reinstalled the capacitor assembly in the chassis. I reconnect the three cable connectors, so I'm ready to power this up!
I plugged in and switched on the AC power. It started right up, with both drives seeking back to home position, and both chassis fans are turning just fine. Each drive's motor is on, looks like, all the time, just as the DEC RX02 drives. I guess this is normal.
I put my working floppy into each drive, closing the door each time, and seeing the floppy spin just perfectly. There are no odd noises, so I think each drive is clean and well enough lubricated. Very nice! As I release each drive's door, the floppy pops out about an inch. Nice drives.
I think this unit is ready to go, once I can find a replacement for the snipped-off cable. For now, I'll reinstall the top cover.
21-Sep-2008
Somewhere along the line, probably while doing functional testing of the two H-11A units last year that this subsystem pairs up with, I fixed the ribbon cable. I simply removed the short end from the internal controller, and attached a new 34-pin connector to the long end of the cable that was with the H-11A 2-switch computer. The cable is now about 14 inches shorter than originally, but that presents no problem.
21-Sep-2008
Also done sometime in the past year or so, again, probably while doing the H-11A checkouts, I powered this system up and found that the voltages were perfect. Continuing, I connected it up to each of the H-11A computers and used it as a boot device. It works perfectly.
I have not yet determined how to utilize the 'Extended' mode, or how to format floppies, though my reading suggests that this subsystem is capable to doing so. I have the documentation, so a bit of reading will undoubtedly give the details of how to initiate the formatting procedure.
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