deskthority

Hello,

So after having all the pieces for almost an year, I finally found the time to disassemble/clean/reassemble/change controller on a 3178 board.

The problem is that 3 columns are dead :



I've visually checked and there are no shorted contacts on the controller or adapter; I can also test with a multimeter, but IIRC some pins do go to GND anyway so some might be "shorted". Any idea which pins on the ribbon cable correspond to the affected columns?

Ok, so I fixed the problem(s).

tl;dr 2 solder points were unreliable.

I used the pic from "Appendix A: Installation in 3178s and derivatives" from here and determined which Model F PCB pins are the columns.

Then I ran a wire dirrectly from each pin to the corresponding point on the xwhatsit controller and found that the columns work. After removing the "test" wires -> multimeter to the rescue: tested the end to end connection on the offending pins and it only showed connectivity once in a while. I resoldered those connections, and for a good measure the other "suspicious" ones and it works great.

alinh wrote: ↑Ok, so I fixed the problem(s).

tl;dr 2 solder points were unreliable.

I used the pic from "Appendix A: Installation in 3178s and derivatives" from here and determined which Model F PCB pins are the columns.

Then I ran a wire dirrectly from each pin to the corresponding point on the xwhatsit controller and found that the columns work. After removing the "test" wires -> multimeter to the rescue: tested the end to end connection on the offending pins and it only showed connectivity once in a while. I resoldered those connections, and for a good measure the other "suspicious" ones and it works great.

Oh, this is very helpful
I also have some issues with my AT and the xwhatsit controller: the last column on the right is dead and the 3 LEDs stay on all the time