Resurrecting a few 128k/512k boards

[IlikeTech]

Also, please use sockets for swapping chips like this.  Much less damage to the board if you have to make changes and makes finding bad chips much faster.

 

[LaPorta]

Yes indeed. I have a few clip-to-size sockets so it is easy.

 

[LaPorta]

Ok, so almost three years hence, I am back at this project. I have sold or traded most of the boards (including one for known-good RAM chips - thanks @Pushpull76 !). I desoldered that chip noted above and put in a socket. I sourced about twenty sockets, so I can theoretically replace them all. I still get nothing from the new chip, but I’m wondering if I a. Damaged all the RAM, or b. Have another issue with the board. Perhaps I should be scoping for signals, but I don’t know what to look for.

 

[Pushpull76]

Ok, so almost three years hence, I am back at this project. I have sold or traded most of the boards (including one for known-good RAM chips - thanks @Pushpull76 !). I desoldered that chip noted above and put in a socket. I sourced about twenty sockets, so I can theoretically replace them all. I still get nothing from the new chip, but I’m wondering if I a. Damaged all the RAM, or b. Have another issue with the board. Perhaps I should be scoping for signals, but I don’t know what to look for.

 

[LaPorta]

Well, the analog board is fine: powered my spare, working Plus board without issue. Definitely an issue on the 128k.

 

[Pushpull76]

It’s a thread opened by John for his 128k motherboards but, a few days ago, I exchanged with him some memory chips for a damaged one…so maybe it’s the right place to post my repair updates

I basically desoldered all the memory chips to use sockets.

 

[LaPorta]

Please do! I want to see your progress as well.