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WANT! Compaq SLT/286 Power Supply (USA)

I know this is an old thread but I literally just bought a working SLT/286 with docking base. I can only power the unit up with the docking base connected which used a standard AC power cable. I would like to know the pinout of the ac adapter so I can build one. I think but am not totally sure that the power connector to the slt/286 is the same cable for the keyboard on the compaq portable I and portable II.
 
I have never found the pin-out for that connector. I know a good little bit about these, as they are my favorite vintage PC laptops, but I have never found out the PSU pin-out unfortunately.

Congrats on getting one of these VERAULT! These machine are fantastic. They're extremely reliable too (aside from the original hard drives, which are a little iffy nowadays). No nasty, SMD electrolytic caps to speak of; all tantalum on the motherboard. All of the electrolytic caps in the internal PSU are extremely high quality, and I haven't had any issues with them. They spared no-expense on the construction of these (I guess they shouldn't have with a starting price of $5,399!). The detachable keyboard is very nice too. Also, they look AWESOME!

The 386s/20 variant is also just as reliable.

I've had these apart so many times I could dissasemble one blindfolded. I've got 5 of these machines (3X 286s and 2X 386s/20s).
 
Well Im not sure the status of the hard drive so thats untested (not holding my breath).
I saw an article Tezza wrote on his website about modding the dallas chip and attaching new battery leads. I will definitely do that. I may try to make a new battery pack one day also.

My unit came with 2.5MB Ram, was that stock?
 
I have done the clock chip mod on one of mine, and I must say, it’s very nice for it to boot straight off of the hard drive like it’s supposed to. I actually desoldered the chip from mine to do it (used a desoldering station).

The 2.5MB of RAM could be original, or it could have been added later. These could be ordered with as little as 640KB of RAM, and as much as 3.7MB of RAM. They can go up to 6MB believe with aftermarket memory modules, but you’ll likely never find any, as these are proprietary memory modules.
 
2.5 megabytes of RAM is plenty. so the shielding of the keyboard cable is completely crumbling like Wax just like my former Compaq portable 3 keyboard cable. Any ideas on how to remedy the situation?
 
Short of replacing the cable, no. All of my SLT/286s have this problem, but strangely enough, both of my 386s/20s have perfect cables with nice, flexible rubber still. Getting the length on the able right would be critical because of the cable has to fit in the little space behind the keyboard. Also, the coiled part of the cable would have to be the same diameter.

Also, another thing I forgot to mention is that if you have the original hard drive (Conner CP 3021, 3021i or 3041), check and make sure the gasket has not melted. If it has melted, don't use it until this as been corrected, as it could ruin the drive.

To fix this issue, remove the cover (these old drives are pretty tolerant to dust, so don't worry), clean ALL of the goop out of there, reinstall the cover, and seal the drive all around with silicone.

Another common-killer of these drive is the piece of insulating foam between the circuit board and the drive's housing deteriorates, causing the board to short out. Once this happens, the drive will no longer spin or anything. It basically kills the PCB. To fix this, take the PCB off and get all of the old foam out. Then, take some cardstock paper, cut it to the right size and there you go, you now have a new insulator.

If your drive has already shorted out and is not spinning, you'll need a new PCB.

The foam for the PCB is a given, replace that no matter what before you use the machine. For the gasket, as said above you'll have to check it. You'll know if it has melted or not because you'll see a browinish colored goo all around the drive.

I've got a drive that I have done all of these thing to, and so far it has been working fine (not even any bad sectors).
 
thanks for the heads up, I will investigate the drive before use.

Now if I can get enough info to make an ac adapter!
 
So I reached out to Tezza as he as a working SLT 286 with external PSU. I asked him to post the pinouts of the AC adapter without load and this is what he found: compaq slt-268 pinouts.jpg

Whats strange is all the voltages DC are negative. I have never seen anything like that before. Plus the -7VDC voltages, shouldnt those be -5VDC, perhaps a regulator issue?

Anyone have any ideas on this, something doesnt seem right about it.
 
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