Some mobos require battery to be present, otherwise RTC/CMOS doesn't work properly. Try connecting something to the external battery header, 3x AA pack for example is cheap and easy to use (and the wires can be long, just make sure nothing gets pinched between cards or cut on some sharp edge).

thanks, today i tested the mobo with both x1 3.7 volts battery as well as serial-ing x3 AA batteries (4.5 volts) and neither made any difference. i noticed the memory only counts up to 512k. if i add more ram, the mobo sometimes hangs BEFORE the memory count and once or twice when it finished counting, it still showed just 512 kb (even though 1 Mb) was installed

Is the jumpering correctly set for 1MB?
As for the "very minor battery leakage" - both 8-bit slots have blueish contacts, this indicates it wasn´t so minor after all. I would look for the cause of the keyboard issue right there.

Cleaning with isopropyl alcohol/reinserting the BIOS chips can make a difference if the board has some oxidisation, even if it's not near the battery.

Does this happen with all cards (escpecially IDE controller) removed?

Is there a twist in the IDE cable on the controller side? For3me it seems the HD is not connected correctly. Try to remove it...

Predator99 wrote on 2024-04-14, 12:06:

Is there a twist in the IDE cable on the controller side? For3me it seems the HD is not connected correctly. Try to remove it...

Good catch. I didn't even notice it at first.

OP, please disconnect any HDD or floppy drives, _along_ with all the cables. Whatever you have connected there to the Super IO card should not be connected with the twisted part of the cable at the card.
Always run these tests with the bare minimum hardware required, and only when that works you can add more cards and drives.

Does it get far enough to complain about no keyboard if you leave that unplugged? Some boards are picky about keyboards, or some keyboards are picky about boards.

thanks for all the help guys. love this forum. just as reference here is a similar 286 mobo which i found closest physically to mine https://theretroweb.com/motherboards/s/abc-co … ct-286-ver.-1.2

Yes you are right about testing with no cards attached. I removed everything but still same failed result. mobo recognizes i.e. missing bank zero rams or the graphic card (if not present) and makes appropriate beeps but every time I still get the dreaded blinking cursor right after successfully counting the first memory bank.

with or without keyboard connected mobo still stops at the same point, I tried different keyboards (even couple XT keyboards!!!) but mobo seems not to care at all. I reckon if problem is keyboard circuitry related then mobo should at least complain about something?!

I cannot see any jumpers to set for more memory ram. I don't think there is any.

last night I found some corrosions which I had missed earlier: around the area between keyboard to the keyboard controller IC. this weekend I will re-clean the mobo with vinegar and wash with Isopropyl this weekend and attend to any oxidisation on BIOS chips or other chips too.

it's annoying when there is no on-screen error messages or beeps or even then diagnostic card numbers are not helpful

BTW, I am so glad the SIPP rams were so short-lived !!! no wonder. the damn things are so badly designed and are pain to pull out and put back. my finger tips are sore hehe