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restoring an old ibm ps/2 l40 sx

Did you replace the old cells with NiCad or NiMh batteries ? The pictures in that link
show NiMh batteries, but I think they may have different charging characteristics than
the original NiCad cells.

Also, are the new batteries fully charged when you put them in the pack ?
 
i believe they are NiMH, but the tutorial said that was OK.

They were not fully charged...should they be?
 
sona1111 said:
i believe they are NiMH, but the tutorial said that was OK.

They were not fully charged...should they be?
Click to expand...

In most cases the NiCad charger should work okay with NiMh batteries. If it
works for the person that created the tutorial it should be okay. It shouldnt
really matter if the batteries are fully charged, I was just wondering if somehow
the charger was detecting they were already fully charged.

If you have a voltmeter it would be a good idea to measure the total voltage
just to make sure they are connected correctly and no cells are bad. Looking
at the pictures the batteries are all attached in SERIES which should yield
9 X 1.2v = about 10.8 VDC
 
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thanks for your reply..again.

I am kind of mad at it right now. I actually charged the batteries on a standard charger, and lined them all up end to end and took a wire from each and to the + and - and it still will not run!

I actually figured out annoyingly that the little "chargeup and back to normal" that appeared just happens when you put the battery in, even if their are no cells attached!

So..i have no idea what is wrong...unless its just something with the main board.
 
Were you able to measure the total voltage and verify its about 10.8 ? I guess its possible
that soldering the wires to the battery could damage the battery although i have soldered
many like this and never had a problem.

Will the computer run when attached to AC power even though the battery was dead ?
 
yeah, the computer runs fine on wall power. (did you read the rest of the thread? no offense)

and i do not have a voltmeter currently. :(

i tested a few of the batteries in other devices and they seemed to work fine, but i guess i can test all of them.
 
Are you lining the batteries up in series or in parallel?

I highly recommend that you get yourself a voltmeter. They have some really cheep ones at radio shack (under $20) that work well as basic units.
 
I found this spec on the L40 battery, so the cells in series is correct :

Replacement Battery Pack for IBM PS/2 Model L40SX (Beige)
Features: NiCad Main Battery Pack. Voltage: 10.8 Volt. Capacity: 2400mAH. Brand: ENERGY+

I have never seen any 2400mah NiCad cells so I wonder how they can make that claim.
If they're actually using NiMh batteries that 2400mah sounds reasonable.
 
well i found the problem... Getting the voltmeter was a very good idea.

anyway something was wrong with the wire i was using...copper and normal metal do not mix.. i guess..

anyway with 9 batteries in series i am actually reading about 12.4 volts on the meter. FYI
I can now get the computer to start on batteries but the alarm goes off right away and it goes into standby before i can do anything. Charging it after this results in a short amount of charge time.

Is their any way to stop the computer from automatically entering standby when it detects "low battery"? I do not think the battery, 9 new AA cells, would really drain completely in 10 seconds.

thanks.
 
Also, i just got that pocket Ethernet adapter. (xircom)

I put put it in the parallel port and plugged it in and it lights up, however the self test on the floppy says it is not detected.

not sure what this is about.
 
Did you ever get the problem with your battery pack solved?

I also have an L40sx I'm planning to restore. I've been toying with the idea of wiring up the battery pack as you've done.

Right now, I've got to replace the hard drive and replace both internal batteries (IIRC the smaller one in your pictures allows the computer to stay alive while one swaps the internal battery packs, while the larger lithium cell near the a/c adapter is for the CMOS). I also need the flip-down cover for the parallel port and a/c adapter on the back side, but I doubt I'll be able to find one without purchasing a parts unit. I was lucky with my purchase - it came with 12mb RAM, the internal dialup modem, a NIB trackpoint mouse, the the reference diskette, the demo diskette, 3qty keyboard overlays, and all documentation. I'm also toying with the idea of modifying a 16mb SIMM to max out the RAM in this system. We'll see.
 
I saw your thread when I was looking for information on the L40 keyboard, I might be able to help you replace or fix it -

IBM produced an external version of the L40 keyboard, called the Model M4. Here's a picture of one -

picture.php


I have a similar version of this keyboard (M4-1, which has a Trackpoint), and from dismantling it, it looks like IBM took the keyboard unit from the L40 laptop, and just designed a housing for it. The M4's keypad connects to a controller board inside the housing using the same sort of ribbon cables in your picture.

There's a company called Unicomp that ended up owning IBM's keyboard division that still sells these M4 keyboards. Their site claims that they are out of stock, but they do a repair service, and the people who run the company are really helpful, if you asked for a replacement keypad for an IBM M4, they might be able to help you.

That failing, you can try opening the keyboard assembly itself. On the underside, there's a little plastic wedge in the center, if you push it down you can slide the thing apart. I'd say that where the dead keys are, you will see a tear or erosion of the membrane traces. This can be repaired using conductive glue to patch up the failure in the traces.

There used to be a guy on eBay who sold the special "Trackpoint" (a rather nifty mouse that could be converted into a trackball) brand new in box for $5, unfortunately I can't find any...

ibm_trackpoint.jpg
 
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