Need help identifying 386 board and RAM

[dvmopar]

I have a 386 machine that I pulled from a local business's attic and I've been having some issues with it. I haven't done much troubleshooting, but based on the fact that it worked correctly for only a few times when I first got it, it's likely a dead battery issue that just had barely enough charge when I got it. I have since removed the barrel battery which didn't leak so corrosion isn't a worry.

The RAM appears to be 2 megs by 4 bits, since just one stick won't get recognized and both sticks in will POST bad.

If there is any documentation you can provide about the board also, that would be much appreciated.

There's not much information, above the copyright between the ISA slots it says something like "386SX BOARD".

 

[modem7]

The RAM appears to be 2 megs by 4 bits, ...

Looking at the photo of the SIPP ('stick'):
Each KM41C1000 chip is 4M (M, not MB) of 1 bit. 9 of those chips, 8 being for data, and one being for parity. So, the SIPP is 4 MB sized, with parity.

... since just one stick won't get recognized ...

The SIPP supplies 8 data bits. On your motherboard, there are two SIPP's per bank, because the 386 is a 386SX, i.e. data path is 16 bits wide. Two SIPP's (8 data bits) are mandatory per bank in order to achieve 16 data bits for the 836SX.

With those SIPPs, one bank is 8 MB (i.e. two 4 MB SIPP's).

For diagnostic purposes, only bank 0 needs to be populated.

With only one SIPP in bank 0, there is in effect, no bank 0. Bank 0 is critical to the motherboard, and the POST will fail early when the POST goes to do a test of low RAM (RAM that the POST and BIOS needs to function fully). What is observed when the low RAM test fails, depends on what behaviour the programmer decided to put into the POST. You may or may not see a message on-screen.

 

[dvmopar]

Sorry, I retyped the RAM section and forgot to add everything I had before. The machine has 4 megabytes total with the four SIPPs installed in banks 0 and 1, it used to have 6 when bank 2 was fully populated, and I just took bank 1 out and it's showing 2 megabytes recognized.

I must've had 5150 in mind when I said 4 bits per SIPP, don't know why it came out that way.

 

[Ruud]

Each KM41C1000 chip is 4M (M, not MB) of 1 bit. 9 of those chips, 8 being for data, and one being for parity. So, the SIPP is 4 MB sized, with parity.

No, 1 MB + parity.

 

[modem7]

No, 1 MB + parity.

Yes. I goofed.