Thinkpads Forum

I just upgraded the CPU in my 770Z to a 650Mhz PIII, and I did not do the speedstep modification, so I understand it should be running at 500Mhz.

I also replaced the "hidden" RAM with a 256Mb PC-100, and installed another. (512Mb) They are 8 chip, not low density, but that doesn't matter because they are PC-100 not PC-133. I don't have another compatible computer to test them in.

When I turn it on, all it does is make one long beep then a short beep that sounds a little lower pitched. The screen does not light up or turn on and it does not attempt to boot.

Obviously I put something together wrong, but I don't know what. Has anyone else had this problem? What was it? Any help at all will be greatly appreciated.

Bookworm wrote:I also replaced the "hidden" RAM with a 256Mb PC-100, and installed another. (512Mb) They are 8 chip, not low density, but that doesn't matter because they are PC-100 not PC-133.

I think it does matter whether they are low density or not. To use a 256MB chip in a 770Z, you should use a low density chip.

I can't quite tell your memory config from what you wrote. Is this it?:
Slot Hidden: 256MB
Slot 1: 512MB
Slot 2:

If so, then I would recommend something more like this:
Slot Hidden: 128MB
Slot 1: 256MB
Slot 2: 128MB
And that'll max you out. You can't use a 512 MB chip in a 770Z if that is what you are trying.

Alternatively, you can do:
Slot Hidden: 256MB
Slot 1: 128MB
Slot 2: 128MB

In both my recommendations, the strategy is to reduce the number of low density 256MB chips you need to a minimum since they are the most expensive/rare. And I wouldn't put a 256MB chip in the hidden slot unless I had to, since they are a pain in the neck to get out if you should ever want to pull that chip for sale or for use in a different machine.

Phil.

> I think it does matter whether they are low density or not. To use a 256MB chip in a 770Z,
> you should use a low density chip.

Now you tell me. I only heard low density was needed for PC-133.

> I can't quite tell your memory config from what you wrote.

It's:

Slot 1:256Mb
Slot 2:256Mb
Slot 3:Empty

Total=512Mb.

Low density covers both PC100 and PC133, up to 256MB modules; PC66 is too old to be anything other than low density. 512MB SDRAM modules are all high density, despite what some eBay sellers might tell you.

> Low density covers both PC100 and PC133, up to 256MB modules