What about the corroded broken trace on the second picture?

analog_programmer wrote on 2025-02-17, 18:38:

What about the corroded broken trace on the second picture?

Yes, I'll check that.. it doesn't looks broken in person but dirty... perhaps the part in the middle layer is broken. I guess it has to be GND as those usually got corroded but has no continuity with GND.
I guess I'll have to check every ISA lines. Sad thing is that the mobo was working before adding the new battery...

Ernesto22 wrote on 2025-02-17, 19:15:

Yes, I'll check that.. it doesn't looks broken in person but dirty... perhaps the part in the middle layer is broken. I guess it has to be GND as those usually got corroded but has no continuity with GND.
I guess I'll have to check every ISA lines. Sad thing is that the mobo was working before adding the new battery...

Ok, maybe the picture "lies" to my eyes, but you can check it just to be sure. Some of the thinner traces (the ones with darker spots and sections) also look suspicious.

analog_programmer wrote on 2025-02-17, 19:24:

Ernesto22 wrote on 2025-02-17, 19:15:

Yes, I'll check that.. it doesn't looks broken in person but dirty... perhaps the part in the middle layer is broken. I guess it has to be GND as those usually got corroded but has no continuity with GND.
I guess I'll have to check every ISA lines. Sad thing is that the mobo was working before adding the new battery...

Ok, maybe the picture "lies" to my eyes, but you can check it just to be sure. Some of the thinner traces (the ones with darker spots and sections) also look suspicious.

Just to let you know and to say Thanks!!!
Trace was actually broken.. my eyes are not what they used to be. Now its fixed and working..

I could search the BIOS post and found some info https://theretroweb.com/motherboards/s/pcchips-m321-rev.-2.x

Mother says "386/486 Mainboard" does it means it may support a 486DLC cpu?

Missing images from previous post

Ernesto22 wrote on 2025-02-19, 04:34:

Just to let you know and to say Thanks!!! Trace was actually broken.. my eyes are not what they used to be. Now its fixed and w […]
Show full quote

Just to let you know and to say Thanks!!!
Trace was actually broken.. my eyes are not what they used to be. Now its fixed and working..

I could search the BIOS post and found some info https://theretroweb.com/motherboards/s/pcchips-m321-rev.-2.x

Mother says "386/486 Mainboard" does it means it may support a 486DLC cpu?

Glad to see you've fixed the motherboard. Mind that those darker spots on the other traces near the battery place are also "seeds" of corrosion under the solder mask.

As for the "386/486 motherboard" label it probably means 486DLC CPU support.

Sadly, after that last post I plugged a keyboard and added a 2nd 4MB RAM bank... but it didn't recognizes The added ram only reporting the first 4MB and didn't recognized the keyboard either. RAM and keyboard are checked and known workng.
Keyboard lights doesn't even blink at boot... checked theblines near thebarea and all cheks good. 5v and GND are present at the MB socket.. I don't know how to check CLk or data lines there.
One thing I've noticed is that 5v pwr good line and the regular 5v lin at thr motherboard connector from PSU are connected with each other at the motherboard. I amnusing an ATX PSU adapted to AT were I linked 5v Power OK line @ATX to Power good @AT PSU. NownInwonder if motherboard is not using the Power OK circuit if that could lead to any trouble with 5v rail at boot time...

Well, maybe you'll have to check all the traces in the area around the battery. It seems like this motherboard has more battery-leakage damage, than it shows at first glance.

I marked some spots with potentially corrosion damaged traces on your last pictures:

Also remove the keyboard controller chip and the BIOS EPROM chip from their sockets to see what's the situation with corrosion beneath them, their legs and with the contacts of these sockets.