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Compaq SLT/286 RAM

B

Ben12345

New Member
Joined
Apr 26, 2017
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4
Hi Guys,

New member here, but a long passion for vintage computing, spanning from my childhood, when all as I had was old legacy hardware, until 1996 when my parents got me a brand new P75 system!

I recently acquired a dead SLT/286, along with an old Kodak portable printer. Physical condition is all pretty good, and i've just managed to get the SLT going by replacing all of the PSU electrolytics. Booted up fist time without a hint of a problem from the Dallas RTC! Second time, not so lucky... Insert diagnostic disc. Oh well, I knew it was inevitable. I'll have to get the dremel out.

Anyway, i'd like to stick Windows 3 on it eventually, but one problem. My system only has the base 640K ram. Does anybody have any leads on the odd looking P shaped Simms that plug into the expansion slots next to the LED board? I'd like my total memory to be at least 1 meg :)

Cheers,

Ben.
 
Ben12345 said:
Hi Guys,

New member here, but a long passion for vintage computing, spanning from my childhood, when all as I had was old legacy hardware, until 1996 when my parents got me a brand new P75 system!

I recently acquired a dead SLT/286, along with an old Kodak portable printer. Physical condition is all pretty good, and i've just managed to get the SLT going by replacing all of the PSU electrolytics. Booted up fist time without a hint of a problem from the Dallas RTC! Second time, not so lucky... Insert diagnostic disc. Oh well, I knew it was inevitable. I'll have to get the dremel out.

Anyway, i'd like to stick Windows 3 on it eventually, but one problem. My system only has the base 640K ram. Does anybody have any leads on the odd looking P shaped Simms that plug into the expansion slots next to the LED board? I'd like my total memory to be at least 1 meg :)

Cheers,

Ben.
Click to expand...
Windows 3.0 will run on 640k though it's not the most useful that way. As far as finding memory, that's going to be tough, I went through a similar deal trying to find the proprietary memory expansion for my Compaq Portable II and Portable III, in the end with those I just installed ISA memory cards, sadly you can't go that route on a laptop :-/
If someone could find schematics for the memory slot, or if someone had a memory card they could provide schematics for, it would be possible to make your own memory card clone, since it probably just uses off the shelf DRAM chips.
 
Hi,

Yes, now you mention about Windows 3 running on 640k, I seem to remember about 22 years ago putting it on an old Amstrad 286 PC clone with 640k, but struggled to get a serial mouse to work on it. Maybe I was thinking that 3.1 needed 1 meg?

This is what the memory looks like (I borrowed the photos from a website that I don't remember the address of). I was hoping that someone might have had some pulled from one they'd broken up for parts.

20141i.jpg
20141j.jpg

I'll keep hunting :)
 
You don't by any chance have figured out the power supplys pinout? I got one but no psu. and frankly the web hasn't been helpful in that case.
 
I did try to figure out the pinout, well pin-in of the internal DC-DC converter, but it didn't seem straightforward. I then had a brainwave and injected power into the machines battery terminals to find that my problem still persisted, which is when I decided to re-cap the internal DC-DC and external PSU.
I can have a go at measuring the power supply itself over the weekend sometime.

If you want to inject power into the battery terminals, from memory, the one on the far left (FDD side) is positive, and the far right (HDD side) is negative.
 
Well I measured the output from the PSU, but didn't get any sensible values for you. I got 5v and 6v, but no 18v between any combination of pins. It seems that the 18v rail doesn't turn on until connected to the SLT, which makes it much harder to measure.

On a positive note, up popped three original SLT/286 1mb memory modules on ebay for a fair price, and they are here in the UK, so I had to buy them :) I pulled the trigger on an SLT/386 too. Not as good condition as my 286, but it's acceptable. All works too, other than the DC-DC supply needs re-capping and the 60mb hdd is a bit unhappy.

I also picked up a Victor V386PX, which looks like a clone of the SLT, but only 16Mhz.

Must stay away from ebay....
 
Ben12345 said:
Hi,

Yes, now you mention about Windows 3 running on 640k, I seem to remember about 22 years ago putting it on an old Amstrad 286 PC clone with 640k, but struggled to get a serial mouse to work on it. Maybe I was thinking that 3.1 needed 1 meg?

This is what the memory looks like (I borrowed the photos from a website that I don't remember the address of). I was hoping that someone might have had some pulled from one they'd broken up for parts.

View attachment 37984
View attachment 37985

I'll keep hunting :)
Click to expand...

I know I'm necroposting, but I have this RAM if you still need it. Two of the exact modules you pictured.
 
Ben12345 said:
Well I measured the output from the PSU, but didn't get any sensible values for you. I got 5v and 6v, but no 18v between any combination of pins. It seems that the 18v rail doesn't turn on until connected to the SLT, which makes it much harder to measure.
Click to expand...

I've done some testing on this topic myself. I've documented what I can, and was able to get most of the pinout - enough to power the computer anyway.
See my blog post here: http://www.vcfed.org/forum/entry.php?812-Compaq-SLT-386s-or-286-Power-Supply-Pinout
 
Greetings fellow vintage fans! Recently jumped aboard the SLT/286 bandwagon and picked up a decent one and I think I made a boo boo. Purchased with Compaq utility disk and sat on it for a couple of days and when first turning on kept asking me about if the utility was run prior to charging battery. I’ve tried both Y and N, editing time, date multiple times and keeps round robin on me and won’t load the drive. Kinda got tired of it (you know something, kinda dawned on me to check if there was a HD, I’m new to this after all)
So shut it off and left it plugged in and went to the other room. 5 min later, I hear a scream from wifey and I ran out. Power adapter was fogging up and boy it stank up the place for hours.
So first use and burnt original power supply. What are the chances. So short of trying to stress upon finding another, I heard of just cutting connections at the PSU and lost the page where I did see it.
But basically bypassing something in regards of the PSU and using a battery to power the unit? I could be wrong but this is one reason I created an account looking for an idea. I solely bought this for nostalgic reasons and live some of my youth for a bit. Anyway thank you folks for at least reading, at least part of it. Cheers
 
Welcome to the forum @Miscdrew !

Things like that have happened to us all, so I wouldn't let it worry you. Does the power adapter still work? Is it physically damaged? If it isn't, i may have just burnt a filtering capacitor, which tend to smell very bad. They aren't critical to system functionality and can easily be replaced.

If the power adapter is physically damaged, it can definitely be repaired or replaced. Where are you located? There may be someone near you who can help.

- Alex
 
Greetings, thank you! Honestly PSU was placed inside a double freezer type ziplock. Wifey wouldn’t have it. Haven’t touched it since it happened 2 days ago, and when it did happen, I did a bit of inspection and nothing out of the ordinary! So atm busy with things but when I get the chance, I’ll open it up and check, should be an easy fix though!
Kinda bummed that it happened First Contact!!!!
 
Hello everyone, I'm finally here with you. My first question is. I have a compaq 286/slt with basic memory at home and I would like to expand the RAM. Does anyone have one?
 
I am also looking for some RAM for my SLT286!

I found a couple of pictures of Kingston modules to add as well!

SLT286Ram_A.jpg
 

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moijk said:
You don't by any chance have figured out the power supplys pinout? I got one but no psu. and frankly the web hasn't been helpful in that case.
Click to expand...
This was posted online from a person that had the car charger cable: the +12V pin is the top pin closest to the rear of the computer, the pin directly below that one is Ground.
Check the picture and the orientation of the pins and the snap clip that holds the plug in.
Hope this helps someone!


Actually - this was posted here!

 

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