(last updated: 01-Jun-2017)
I have re-ordered the boards in this system, otherwise, the current configuration is in its original 'as acquired' condition.
| HEATHKIT H11 | A | B | C | D | |
|---|---|---|---|---|---|
| Q22/Q22 | 1 | M7270 : KD11-HA : LSI-11/2 CPU | WHA-11-16 : 16 x 16 Memory | ||
| 2 | H-11-5 : Serial I/O | H27 : Floppy I/O | |||
| 3 | M8028 : DLV11-F SLU | (empty) | |||
| 4 | (empty) | WHA-11-16 : 16 x 16 Memory | |||
03-Mar-2006
The system was a little dirty and banged up as received. The previous owner had himself acquired it from others, so who knows how many garages and basements this system has been stored in?
The brown packaging tape was removed, but it was very old and brittle, and it left a hard residue behind. I didn't take any 'serious' chemicals to the case, I just used a 'baby wipe' to clean up the surface dust and grime. I'll come back to the residue later.
Right away I could see that there has been some exposure to moisture or water. There are a couple of rust stains on the enclosure's top cover, as well as the rear and bottom around the transformer and power supply.
Under the cover, things looked pretty good, actually...just a few spider webs. The console cable connector was not in place in the back panel, but was hanging loose inside. The card cage was askew since there are no retaining nuts on the bottom to hold it securely in place. Still things look just fine.
I disconnected the printer connector from the back panel, and pulled the floppy interface cable back through, as well. The populated card cage, power supply and front panel switch assembly were removed from the enclosure, which was then vacuumed and cleaned. There is some corrosion/rust on the bottom panel at the power supply bracket attach point and around the transformer mounting screws. On the whole, though, it looks quite benign and localized, and I don't believe there has been any water infiltration on the card cage or other electronics.
09-Apr-2006
I removed the power supply assembly, and then loosened the strap holding the capacitor, disconnected the wires to the two terminals, and removed the capacitor from the assembly.
There is a little fraying of some unusual insulation on a triplet of wires (to and from a choke, I think) that may need some attention. There shouldn't be any problem right away, but as the insulation continues to break down, as it ages, some of the wire may become exposed. And while it is true that these wires are not likely to make contact with anything, given the PS's mechanical design, this situation could develop into a slight hazard. It is something to pay attention to in the future.
10-Apr-2006
After 21 hours (7:16p April 10) at 40V, the current was still at 440uA! Seems kind of high to me, but probably okay.
I discharged the capacitor through the bench supply and disconnected the charging leads. I reinstalled the capacitor in the power supply housing strap, after reconnecting the wires to both terminals. I reinstalled the power supply in the chassis, using two silver screws on the PCB connecting it to the fan housing, and five black screws on the chassis bottom. I reconnected the cables to the fan, the front switch assembly, and the transformer. We're ready to plug this in and see it go!
I connected the AC and switched on. The fan started right up. I swithed DC ON, and saw the voltages change in the backplane power connector. I get good 5V and 12V readings. I also switched LTC ON and saw the line go from 5V to 1.6V, so this must be a low active control.
I loosely replaced the card cage and top cover, pending further operational testing.
17-Oct-2006
After further examination, and a review of the Pictorial sheets that came with the assembly manual, I determined that the backplane is serpentine, but it is a mirror image of the normal DEC backplane. Slot 1 is at the top-right, but the boards are to be inserted component-side down. Turns out that each AB/CD slot is labelled on the backplane PCB on the board side. So the board installation sequence is:
D C B A
1 v--2-- < --1--
v
2 v--3-- > --4--v
v
3 v--6-- < --5--v
v
4 v--7-- > --8--
[only Memory or quad-sized CPU in slot 1]
17-Oct-2006
Well, no luck. At least no ouput on the VT220. I borrowed a console adapter cable from the other H11 to go from the strange rectangular 25-pin connector that these H11's use to a DB25. I don't know if it is wired up correctly or not, so that could be a problem. I did try with a null-modem adapter, and without. In both cases, no console output.
The RUN indicator on the front panel comes on momentarily, then goes out. I tried moving the jumper on the CPU board from W5 to W6, and then removing it all together, with no difference in behavior. My best guess right now is that the console cable isn't correct. But it could be any of the boards, or the cable, or the configuration. So, I'll have to look deeply into everything again.
28-Jul-2007
With the DATAX running, I now have a relatively easy-to-access system that I can test boards from this and the other H11A. Here are the results:
- M7270 : LSI-11/2 CPU : GOOD - WHA-11-16 : 16KW Memory (0KW-based) : GOOD - WHA-11-16 : 16KW Memory (16KW-based) : GOOD
I couldn't get the console (TT:) serial card to give me anything, so I still don't know if it's any good or not.
I then moved the M7270, the 0-based WHA-11-16, and DLV11-J from the LAB DATAX to the Heathkit chassis and powered up! At first I couldn't get it to continue running, it would always halt after one instruction. After fiddling with this and that for a minute or two, I flipped the LTC switch to OFF, and now the system runs! I entered the bootstrap for Will's TU58 emulator and booted from the DD: device! It's alive! This is a big step! And it confirms the recommeded board configuration: Memory in slot 1, CPU in slot 2, SLU in slot 3; that is, CPU (component-side down) in the upper-left slot, Memory in the upper-right slot, and SLU in the slot below the CPU.
Now for a little more fiddling to figure out exactly which front panel configurations work and which don't. I flipped the LTC switch to ON and the system just kept going! Hmmm.... Doesn't seem to matter one way or the other. I need to learn more about the LTC and what purpose it has.
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