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Ok I will get my new chips Tuesday so I will remove it and put in a socket for now and wait for the new. I also get the new memory so will do the ls32 first and if need the memory after

Here are the pics for current machine with issues. In order pic 1 is pin 6 on 74ls32. Pic 2 is pin 4 RW on chip 1, pic 3 is chip 2. Pic 4,5,6 same pins different machine that is working.

Well I open up my other IIc to probe the chips and I get same results. It seems the keyboard needs to be connected to get the proper signal on pin 4. I will send you some pics shortly. Outside with the kids a bit before they disown me.

Thanks. I just order some but had to use Amazon as I need it delivered tomorrow as I have a friend coming to visit me Tuesday from Miami. I live overseas in the Cayman Islands so it’s hard for me to get parts. I know is not best quality but it’s what i can do in a pinch.

I will need to order I don’t have any laying around. I going to see my other machines maybe borrow from them.

i will see where I can borrow a 74LS from to test it. Don’t have any new right now.

Those 5 from pin 6 on 74LS which is the out pin goes to 4 and ram 1 and 2. Ram 3 and 4 I need check as that comes from another source. That is the Aux memory.

Ok here is a full set pin 14 on TMG, one side of resistor, other side resistor, pin 4 in on 74LS32, exit on pin 6, pin 4 ram 1, pin 4 ram 2, pin 4 ram 3, pin 4 ram 4.

The first set of pics are with cpu and rom the last set I send were with them out. I will do with them in.

I hope it’s this but I made a error. This pics and results are with ROM and CPU removed. Does it make different? I can redo with them in socket.

The signal starts at the TMG chip as 01 pin 14 good solid signal nice form. Goes to R59 then to the 74LS32 pin 4 comes out on pin 6 and is garbage. See the pics. Going in, out and last is at pin 4 on the ram. Seems everything coming out of this 74LS32 is bad garbage.

This for the 16 chip ram logic board A2S4000. I have the A2S4100 that schematic is VERY bad quality and is on page 407-411 of this attached manual. I decided send the entire manual as it could help you.

sorry can you explain it a bit more I am not super advance on this. Trace the pin 4 you mention or the 17 on chip 1 that is backwards?

4 is the write pin.

I as about to post this. This the first chip and file and shows the PIN number. 2,3,15 look good and same type. 17 is upside down. Inverted. This the only one that is different to all chips and the 4 pins for data lines

Here is the pin out for the ram chips.

The 4 main being rom cpu mmu iou I know work as I tried them in another board. I get replacement memory on Tuesday.

Here are the images for chip 1 out of 4. This the lower end. I did not do pin 1, 9, 18 as these are power and ground and the file names show the PIN number. As this the 4100 board, I am trying to find a clear schematic to get you the pinning info unless you have it already. I do have a schematic...

The rams are socketed with the dual version. Even the cpu rom mmu iou I changed to dual. All rested for good continuity.

Ok I doing some pics of it will post. They look strange on some pins.