Glen M
Experienced Member
I've been gifted an Olivetti M203 motherboard which I'm fairly sure is from a model M290S computer. I have no idea if this works or not but I want to try and power it on just on the chance it does. Problem though is that these Olivetti's all used proprietary power supplies and this one uses a 10pin connector. I've managed to bell out 9 of the pins using the ISA riser for reference and I've figured out +5v, +5v, ground, ground, ground, ground, +12v, -12v, -5v. The last pin though has me stumped. It only seems to be connected to some 74 logic and a custom olivetti IC. Its connected to the logic not the ground or VCC pins so I've no idea what this is doing, any suggestions?
Is it possibly some sort of reset line or power good signal or maybe something to isolate the monitor pass through (this is a feature on my Olivetti 386 all be it, its contained within the PSU).
If I hook everything else up to a do you think it would work without this pin? I suppose there's one way to know but before I go trying I thought I'd ask.
There is also another potential issue... when belling out the various pins I noticed a reading of 167ohms between +5V and the chassis ground which changes to about 200ohms between the +5V and ground pins (at the psu connector but also at components around the board). Surely this can't be correct?
Is it possibly some sort of reset line or power good signal or maybe something to isolate the monitor pass through (this is a feature on my Olivetti 386 all be it, its contained within the PSU).
If I hook everything else up to a do you think it would work without this pin? I suppose there's one way to know but before I go trying I thought I'd ask.
There is also another potential issue... when belling out the various pins I noticed a reading of 167ohms between +5V and the chassis ground which changes to about 200ohms between the +5V and ground pins (at the psu connector but also at components around the board). Surely this can't be correct?