Need help with IBM PS/1 Consultant (1992) – RAM issue? (Beginner here)

Hey everyone,

I recently picked up an IBM PS/1 Consultant (dated 1992) from an estate sale. It was an unknown condition purchase, but overall it seems to be in really good shape physically.

Here’s what it’s doing:

- Everything powers on

- Monitor turns on and shows the correct indicator light

- The PC itself powers up and sounds like it’s starting normally

However, on startup it gives a repeating 4-beep pattern and never displays anything on screen.

At first, I assumed this was because there was no RAM installed (which was true when I got it). So I started trying to fix that:

1. I bought a set of 72-pin 8-chip RAM (16MB FPM) → same beeping

2. Then I tried another set of 72-pin RAM with 12 chips → same exact result

From what I’ve been reading, the 4-beep code likely means it’s not detecting usable RAM.

At this point I’m realizing:

- I probably don’t fully understand RAM compatibility on these older systems

- And I may be buying the wrong type even if it “sounds right”

From what I’ve gathered so far, it seems like this system might need:

- 72-pin SIMMs

- Low-density

- Possibly 4MB modules (1Mx36, maybe 9-chip parity?)

But I’m honestly not confident.

I have basic computer knowledge, but clearly not enough when it comes to older hardware like this. 😅

If anyone can:

- Confirm the exact type of RAM this system needs

- Or point out what I’m doing wrong

- Or even explain this in simple terms

I would seriously appreciate it. I’d love to get this machine up and running.

Thanks in advance!