falter
Veteran Member
Well, I've gone and done it again.
I tried to make a keyboard cable for my A2S1 keyboard, but only succeeded in shorting something, causing the keyboard to stop working. I changed out the TTL chips and restored most functionality (was still interpreting certain keys wrong), and then made the mistake of piggybacking the 555 chip to see if the timing was off. That caused everything to go dark again and now only the CTRL-RESET keys work. I still don't have my scope yet.. and unfortunately this keyboard PCB wasn't in the best shape and the pads you solder to for the 555 chip literally fell off. So I've tried my best to figure out the traces and solder in some jumper wires. I think I have it correct, although the schematic I found differs from what is clearly present on this board.
It is a single piece Rev 1 board (brown mask). I am wondering if anyone out there has a spare they'd like to sell, or if they have any good photos of the area where the 555 is -- front and back. I'm trying to figure out if I've missed a trace/connection somewhere.
THanks again!
I tried to make a keyboard cable for my A2S1 keyboard, but only succeeded in shorting something, causing the keyboard to stop working. I changed out the TTL chips and restored most functionality (was still interpreting certain keys wrong), and then made the mistake of piggybacking the 555 chip to see if the timing was off. That caused everything to go dark again and now only the CTRL-RESET keys work. I still don't have my scope yet.. and unfortunately this keyboard PCB wasn't in the best shape and the pads you solder to for the 555 chip literally fell off. So I've tried my best to figure out the traces and solder in some jumper wires. I think I have it correct, although the schematic I found differs from what is clearly present on this board.
It is a single piece Rev 1 board (brown mask). I am wondering if anyone out there has a spare they'd like to sell, or if they have any good photos of the area where the 555 is -- front and back. I'm trying to figure out if I've missed a trace/connection somewhere.
THanks again!