HP 9000/200 (9816S) keyboard knob repair

[Martin Hepperle]

(06-08-2015 03:00 PM)Paul Berger (Canada) Wrote:  I should check that bulb on my Nimitz keyboard since the dial does not work on it. I wonder if an LED would work, maybe an IR LED.

I also thought of using an LED with a resistor, but then I decided to stick with the bulb. It is important that enough light is shed to the side of the bulb and an LED would concentrate its light more to the front, where it is not needed. The sideways emission is fed into two parallel "channels" to project two thin beams of light onto the rotating disk. The whole system looks very simular to the HP-85 tape drive speed control.
Maybe it works with an LED, but I would not be surprised if the light emission to the side is too weak.
The wheel can be tested in the BASIC editor environment or outside with an oscilloscope.

(06-08-2015 03:00 PM)Paul Berger (Canada) Wrote:  Did you happen to get any software with your 9000? HP produced a software package for the 98640A called "HP98645A Measurement Library" that would make using these cards much easier as there is no support for them built into BASIC or Pascal, which makes using the card more difficult.

Unfortunately I only got a disk with the testing software, which can also be found on the HP Museums web site. I think this software needs the extra test assembly to connect some pins and to supply the right voltage levels.
I have not yet dug deep enough, but I hope that it should be possible to access the card's control registers etc. It would be nice to have the "CSUB Utility for BASIC" software, though, to create the corresponding functions in assembler in the Pascal environment and then make them avaiable to the BASIC environment.

(06-08-2015 03:00 PM)Paul Berger (Canada) Wrote:  For a connector I found that a Cinch 252-22-30-160 fits over the pins securely but the two outside pins, which are redundant grounds are not connected. It appears that there is also a 24 pin version.

Thank you for this tip, I have to see whether I can find this connector here in Europe. However this seems to be a card edge connector - my card has pins...

Martin