Recent content by PhilipA

Though, that reminds me, if I point the pc at the same location the standard MPF-1 ROM starts at, mine will display uPF-1 also.

I'm not entirely sure the difference between mine with the OLS code and the standard MPF-1 (the normal boot is to display uPF-1). I should dump the ROMs some day.

I believe it fair to say that light or UV accelerates the process.

In that case, an echo; don't. It's temporary at best and will end up looking much the same as it does now if you're going to use it or keep it in a sunny or lit room.

Not just sunlight- I have a nearly orange crt monitor that spent its life in a windowless concrete building, illumined 24/7 by fluorescent lights. They emit enough UV to do the same as sunshine. Your 86 is hardly yellowed at all. My 85a is much worse- I think it adds to the character. It'll...

Fun little machine, I use mine to test assembly code for my Z80 and 8080 computers. There's quite a lot of documentation for it, thwy were made for decades as training boards, very popular.

Nope, it would appear track 0 on that disc is unserviceable now. Great.

Argh. I was making a crib sheet of German to English commands last night and decided to write a test file to the Text disc. What it did was corrupt the Text disc. Great. I am going to try rewrite the Text disc with my FLUXTEEN and see if that gets it working again. Phil

Because it would be rude not to have.

Substituted the failed K-type switches in space, return, backspace and left-arrow. With exception of it being the DIN standard keyboard (QWERTZ), it's working.

Okay, got 4 failed keys on the board. Found out how the matrix works; ground the lower pin and that trips the "key pressed" trigger circuit (monostable pulse). Top key hits the key decoder matrix independently, and sets the last pressed code into the output. The failed keys are all Type K...

Yup, need to see what's common to those 3 keys and see if it's repairable.

Space, return and backspace removed from the circuit and everything (mostly) works. Phil

A brief moment tonight to troubleshoot. Sending data down the keyboard bus results in sane replies on the screen. A little digging shows the switches are actually open collector design. I'll make a divider circuit tomorrow to see if the one I pulled out works correctly. If they're all good and...

Yeah, the glue is beginning to degrade. It's not too bad yet, so I'm not going to try remove it.