Challenge: Motherboard from 1994

[aideed]

Turns out there is a bit of smarts on the right board...



I don't think there is much hope for turning this motherboard on, from what I can tell the system waits for the logic on this board to enable the system.

thanks for all the help.

aideed

[evasive]

Got any parts numbers of the chips on that board? It looks to have a backup coin cell battery, is that refreshed already?

[aideed]

Got any parts numbers of the chips on that board? It looks to have a backup coin cell battery, is that refreshed already?

Thats actually a piezo speaker, running from a timer chip. How archaic... ha ha.

[Karlsweldt]

You note you have two identical motherboards, one works, the other doesn't. Set the non-working board to the same jumper settings as the working one, then try it.
One failure point of many older mobo designs was the use of a Dallas Real-time chip or similar, with a non-replaceable BIOS battery. That would die in about 5~7 years, and render the system useless! Without the real-time clock working, the mobo circuits may appear dead. Some mobo designs had that chip soldered to the mobo, others had a socket for it. The availability of those chips is very scarce.. and no real easy way to replace that tiny battery, or apply an external BIOS battery. But look near the keyboard port, there may be a 4-pin header for an external BIOS battery pack, typically a 3.6 volt to 6 volt. If there is a coin cell or only the external BIOS battery connection, then no worries.. the mobo should be good to use.
And check the BIOS chip arrangement. Early BIOS types used two DIPP chips.. one marked "low" or "even", the other "high" or "odd". Ensure they are in their respective sockets! The reason for two BIOS chips was that the micro-technology used today for BIOS chips was not available.. and the circuitry had to be separated into odd and even chips. The "even" chip controlled the 0, 2, 4, 6, etc. binary functions. The "odd" chip controlled the 1, 3, 5, 7, etc. binary functions.

[evasive]

Got any parts numbers of the chips on that board? It looks to have a backup coin cell battery, is that refreshed already?

Thats actually a piezo speaker, running from a timer chip. How archaic... ha ha.

Check the electronics magazines from that era, you'll see how "archaic" it was in that time. You realize you are working with 17 year old hardware, I hope

[aideed]

Oh i know... evasive, old is all I have.

All of my hardware is legacy. Windows NT is the most current OS that we use. Unfortunately we can't upgrade because of hardware limitations; I need to use ISA and EISA cards.

aideed