pull out two sticks and see if it reports 8Mb both in count and in BIOS. just a thought.

Test memory 2 at a time till you find one that is not good.

Please take picture of the 4 modules please.

Cheers,

Modules and motherboard photos attached.

I tried runnşng the board with each individual stick and while the POST RAM count goes up to 4000KB I still get a 164 error and the BIOS reports 17878KB RAM.

I will check using pairs of sticks and report..

I think I know what is wrong. From the PS/1 Maintenance Manual:

The 486SX, 486DX, and 486DX2 system boards (72-pin memory SIMM) have no soldered RAM. All system memory is socketed with SIMMs. Unlike 30-pin SIMMs, which must be installed in banks of four, 72-pin memory SIMM can be installed one at a time. SIMMs supported are 70 ns and must be 36 bits wide.

The SIMMs this PC came with are 32 bits wide Nom-ECC..

I managed to fix this issue. I am detailing the fix here for anyone who encounters this problem later:

Even though I had previously tried to clear CMOS prior to launching this PC, I seem to have done it wrong. I simply removed the coin cell battery and disconnected the power for 1 minutes, and it did give me a date/time error and cmos battery error (or IBM POST equivalent codes) at boot. Apparently, this is not enough and there is a capacitor on the board that holds a charge that can retain CMOS information for quite a while.

So apparently the correct way to reset the CMOS (and Boot password coincidentally) is to remove the coin cell battery, unplug power AND short the two pads below the battery holder for 10 seconds.

Once I did that, upon next boot, I got a lot of POST errors (due to CMOS settings missing) but once I ran the BIOS Configuration Utility, the Memory was displayed correctly as 16MB.

My PS/1 is working perfectly now 😀

appiah4 wrote on 2020-08-23, 13:49:

I managed to fix this issue. I am detailing the fix here for anyone who encounters this problem later: […]
Show full quote

I managed to fix this issue. I am detailing the fix here for anyone who encounters this problem later:

Even though I had previously tried to clear CMOS prior to launching this PC, I seem to have done it wrong. I simply removed the coin cell battery and disconnected the power for 1 minutes, and it did give me a date/time error and cmos battery error (or IBM POST equivalent codes) at boot. Apparently, this is not enough and there is a capacitor on the board that holds a charge that can retain CMOS information for quite a while.

So apparently the correct way to reset the CMOS (and Boot password coincidentally) is to remove the coin cell battery, unplug power AND short the two pads below the battery holder for 10 seconds.

Once I did that, upon next boot, I got a lot of POST errors (due to CMOS settings missing) but once I ran the BIOS Configuration Utility, the Memory was displayed correctly as 16MB.

My PS/1 is working perfectly now 😀

This should be a sticky post or documented somewhere permanently as what you have just described is the proper generic way to clear CMOS memory on just about any board .

Asus boards manuals says same thing, main power disconnected, but with two in one, move jumper over for a while does two things, this disconnects battery's supply and short out the cmos memory's supply to drain out remaining voltage for the CMOS memory will make setting to vanish properly. Remember CMOS memory part is really good at holding it's memory on very little voltage except the active circuit stop working (clock).

Cheers,

Wait a minute here...
My IBM PS/Valuepoint 466 is playing picky about ram with the same kind of error: post test counts way too far and gives me a mem error.

So by resetting the bios this way it could be the solution?

(Did I smell some 32MB ram somewhere?)

appiah4 wrote on 2020-08-23, 13:49:

I managed to fix this issue. I am detailing the fix here for anyone who encounters this problem later: […]
Show full quote

I managed to fix this issue. I am detailing the fix here for anyone who encounters this problem later:

Even though I had previously tried to clear CMOS prior to launching this PC, I seem to have done it wrong. I simply removed the coin cell battery and disconnected the power for 1 minutes, and it did give me a date/time error and cmos battery error (or IBM POST equivalent codes) at boot. Apparently, this is not enough and there is a capacitor on the board that holds a charge that can retain CMOS information for quite a while.

So apparently the correct way to reset the CMOS (and Boot password coincidentally) is to remove the coin cell battery, unplug power AND short the two pads below the battery holder for 10 seconds.

Once I did that, upon next boot, I got a lot of POST errors (due to CMOS settings missing) but once I ran the BIOS Configuration Utility, the Memory was displayed correctly as 16MB.

My PS/1 is working perfectly now 😀

Thank you so much for posting this fix! It not only fixed my memory error (same one you had), but also fixed my PS2 mouse issue! Previously I had to start the computer, and then reboot it to get the mouse to work. Thanks again!

airs wrote on 2022-01-14, 04:48:

appiah4 wrote on 2020-08-23, 13:49:

I managed to fix this issue. I am detailing the fix here for anyone who encounters this problem later: […]
Show full quote

I managed to fix this issue. I am detailing the fix here for anyone who encounters this problem later:

Even though I had previously tried to clear CMOS prior to launching this PC, I seem to have done it wrong. I simply removed the coin cell battery and disconnected the power for 1 minutes, and it did give me a date/time error and cmos battery error (or IBM POST equivalent codes) at boot. Apparently, this is not enough and there is a capacitor on the board that holds a charge that can retain CMOS information for quite a while.

So apparently the correct way to reset the CMOS (and Boot password coincidentally) is to remove the coin cell battery, unplug power AND short the two pads below the battery holder for 10 seconds.

Once I did that, upon next boot, I got a lot of POST errors (due to CMOS settings missing) but once I ran the BIOS Configuration Utility, the Memory was displayed correctly as 16MB.

My PS/1 is working perfectly now 😀

Thank you so much for posting this fix! It not only fixed my memory error (same one you had), but also fixed my PS2 mouse issue! Previously I had to start the computer, and then reboot it to get the mouse to work. Thanks again!

Ha! Another happy PS/1 owner. Best IBM there is, IMO 😀 Enjoy.