Thanks a lot Exxos for this information.

Have a nice evening.

Take care and stay healthy.

See you.

Hello Exxos, For your information, I just received the RAM and the two reset switches that I ordered from you. I'm still waiting for COMBEL and VIDEL to have them soldered and see if that solves the problem (I hope it will ...): they arrived in France and they should be at my house soon. One questio...

Continuity test done between XROM2 (pin 199 of COMBEL) and pin 3 of ROM : less than 1 Ohm => XROM2 and ROM pin 3 are connected...

Hello, I made the proposed test. I first checked that without any modification, I still had +5V on pin 3 of ROM and that pin 47 and 48 of expansion port were still at +5V : it was the case. Then I put ground on pin 47 and pin 48 of expansion port (see below picture; I checked that I really had 0V on...

Yes it was A1 and A2.

Ok well understood. I will try this (probably tomorrow morning) to force A1 and A2 to 0 and I will keep you uptodate.

Yes obviously you are right for the VIDEL : it could also be faulty... I did not fully understood for forcing the 0V on the two pins that are at +5V : you mean make a connection between a pin at 0V on the expansion port and the two other pins that are currently at +5V to force them at 0V? What does ...

I just checked the continuity between the Address 1 to Address 23 on the expansion port and the corresponding pins on the CPU (putting my probes directly at the outlet of plastic core of the CPU and everything is ok (resistance less than 1 Ohm) : so the solders are ok between CPU and expansion port....

Hello Exxos, Thanks for the "Well done" and thanks for your feeback. Yes I measured yesterday the resistance to 5V for each pin (directly on CPU pin) with a 4,6 kOhms for Ax addresses and 10 kOhms for DX addresses. Concerning the +5V on A1 and A2, I first measured them on CPU pins directly...

Hello Exxos, I succeeded in desoldering properly and gently the pin 1 of VIDEL (see below picture). I am still without ROM and without RAM. In that situation with the pin 1 of VIDEL connected to nothing, I checked the voltage for addresses on expansion port and checked that every address pin is at 0...

Thank you very much Exxos for all your advice and answers. I think that desolder it gently without doing any other damage is something I can do. Resolder it would be another story... I fully understand the purpose of this VIDEL deactivation: I will therefore try this "mod" to try to furthe...