Ram on T23 Doesn't work

[copeloalejandro]

Hi there!
I got a thinkpad T23 with a Memory RAM of 256Mb. I bought 2 X 512Mb pc 133 Ram. But as soon as you install the new ram on the computer, it wouldn't start. It lights but screen remains black and light meaning battery getting discharge doesn't light. Once turn it off and removed new RAM and install original one, it will work as always.
There is anything I can do to install the new RAM?
Thanks!!!!

[ajkula66]

Welcome to the forum!

I'd suggest returning those DIMMs to your supplier, and purchasing some "known brand" RAM, even used will do perfectly fine...Micron, Hynix, Kingston, Elpida - whatever you can get your hands on.

RAM upgrade is "plug and play" on all the Thinkpads that I could think of right now...

[Majestic]

A couple of other suggestions before sending the modules back....

Test the memory slots. Try your original 256mb module in both slots to make sure they are working.

Then try installing the new memory modules one at a time to see if the system boots with an individual module. It's quite possible one module is bad.

[Thinkpad Lover]

Hi,

I think you will need Low-Density 512mb PC133. Check- does the RAM you purchased have 8 chips on each side? If not, then it's High-Density 512mb PC133 that you purchased (4 chips on each side, total of 8 ). Your T23 should be about 1.13 GHZ speed which is common. (It could also be 866MHZ, 1.06GHZ or 1.2GHZ). A general rule of thumb is that Low-Density RAM is required for machines with < 1GHZ speed and High-Density will work in machines with > 1GHZ speed. However, the T23 is right on the borderline there at 1.13 GHZ speed and I think it probably needs Low-density PC133 (which has 8 chips on each side,total of 16).

But as soon as you install the new ram on the computer, it wouldn't start. It lights but screen remains black and light meaning battery getting discharge doesn't light.

What you're describing here sounds like the way a laptop behaves which needs Low-Density but gets High-Density RAM. Check out this thread. He had a similar problem with Low-Density/High-Desity 512mb PC133 RAM on a T23: http://forum.thinkpads.com/viewtopic.ph ... 29&start=0 Also read the thread mentioned in the final post. (And you'll be as confused as can be as to whether T23 can always take High-Density or not).

Opinions vary over the necessity of Low-Density versus High-Density on a T23 but I think it may depend on the particular machine in question (some T23's operate at a faster speed and can perhaps handle High-Density while some may not be able to). What is the exact 7-digit type/model number to the left of the Serial Number of your T23 (for example: 2647-3U5). Just curious about the speed of your T23.

I don't have a chance/machines available right now but what I will do one day is test a couple of T23's which have different speeds. It would be nice if we could settle the confusion and clear up the issue of using High-Density RAM on a T23 once and for all. However, one additional issue which complicates the matter is that 512mb High-Density modules from different manufacturers can behave differently in a machine such as a T23, which is right on the borderline in the battle of High-Density versus Low-Density. Seems that some High-Density modules work better than others on these kinds of machines.

See this thread here: http://forum.thinkpads.com/viewtopic.php?f=5&t=98788 An A30p can take 512mb PC133 just like a T23. He told me later that he ended up buying some Transend 512mb PC133 modules which are working fine. Forgot to ask him if they are High-Density or Low-Density.

As I said if those were High-Density modules you purchased, I think you probably need Low-Density (8 chips on each side). That's the safest thing to do/easiest and most definite solution in my humble opinion.
Daniel.

[ajkula66]

There are *no* low-density 512MB PC133 laptop DIMMs.

All of them are the same.

T23s are actually running at 133Mhz. It's the slower, older P3 units that were originally designed for PC100 RAM that have issues with high-density DIMMs.

However, defective and/or untested, bottom-feed RAM will make these machines choke, as resiliant as they might be in many respects.

[Harryc]

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