There were a few OEM PC's from the 80's that had proprietary connectors.
Two that comes to mind are those from Olivetti, like the M19 & the M24 (AT&T PC 6300) and the Sperry HT (Leading Edge MP-1676L). Even these days, you still have OEM PC's using their own proprietary PSU's or connectors.

I think that finding parts for any PC that is 30 years old is a challenge, not just OEM PC's. If it is just about replacing capacitors, then it's not too much of an issue to find replacements.

HP Vectra also had proprietary connectors. So is the answer that it is generally too much trouble to buy those old oem pcs to make it worth it?

Baoran wrote:

Is there any point in buying 80s oem pc that doesn't have standard psu and even the power connector on the motherboard isn't standard AT? Even if the pc would work right now, I assume there would be no way of getting spare parts for such old PC, right?
30 years old pc would most likely not last very long anymore considering how old the capacitors in the psu are.

Because some of them look unique? At that time, there were many "home" PCs that followed the "all in a keyboard" design of 8 bit computers. Think about Sinclair PC200 and Schneider EuroPC.

One thing I will say is that some old computers were apparently made with very high quality components because they still work. My biggest concern with older systems is tantalum capacitors because I've had one explode on me, I've had one short out (no fireworks) and I've seen two in the past few months on old boards that had exploded at some point in the past. This isn't necessarily an issue of quality though. Tantalums that don't explode after sitting unpowered for 25+ years will probably work fine for an extremely long time if they are powered on periodically.

My IBM 5150 and 5153 monitor still have all original parts aside from one memory chip I had to replace. I don't know for sure but I think this particular system is from the mid to late 80s, so its more than 30 years old.

I mean pc using something like this:

You could probably rebuild the PSU if you had to. I don't know what sort of ICs they use in it, but it is possible drop-in replacements are available for those as well. I imagine there is a possibility that others have done the detective work already, but the pool of possibilities of that at vogons is rather smaller as I believe the average age here is dropping.

I do know that the line suppression cap on the larger, sideswitch PSUs for some of the IBMs tended to blow up. Only thing I have is a Kingpao PSU, and I haven't used it for any projects (yet).

All of the best quality PCs in the 80s were made by big names like Compaq, AST and ALR. If you're looking for a good 286, I would at least consider one of those. For more standard stuff though, Everex was also really good.

Thread: yes.
Because hacking together a custom powersupply is cheap and easy today thanks to low noise dc-dc converters from china. As long as you know the voltages for each pin and supply enough current. It doesn't have to be perfect. I made my own ATX to AT adapter which worked alright. No reason that I can't splice those same wires into some other form of connector for an OEM.

Old computers rarely show up for sale where I live, so I generally don't have many to choose from. Of course I would much rather find 286 with standard AT motherboard and standard power supply so that it would be easier to replace parts in it.

The truth is as vintage computers get older, we as enthusiasts who want to keep using them will need to obtain more repair skills. I started doing this stuff we talk about here in Marvin 15 years ago and back then I could screw up and break stuff all the time because I was getting rained on in ISA cards and 486's like pennies from heaven. But as the 2000's dragged on and the well started to dry up and more people got into it, and more of these machines got recycled, we've slowly had to go from "oh, VGA card is fried" or "Oh, I can find another IBM PS/2 Model 30 for $5" to "Well darn, time to dremel that Dallas Clock chip" or "Time to fire up those Soldering irons and go troubleshooting capacitors for the next few hours".

I've already vowed that the next time my PSU in one of my vintage machines blows up, I'm repairing it. There is no excuse why I can't. I have a VOM, I have a soldering Iron, a Oscilloscope is on my radar. I can wind and repair guitars pickups so PC PSU transformers are not that much different, and I've learned a lot about the kinds of adhesives and materials used in that stuff over the past several years. That's what the retro computer guys from the 70's and early 80's have been doing for even longer than I have - when their IMSAI 8080 goes down, they don't exactly have the guy who stayed up all night eating pizza and drinking beer some lonely winter night in 1975 to come on down and help them, nor would he likely do so if asked. I'm also taking up building guitar pedals - and let me tell you, there are more things CMOS than just your BIOS setting storage.

That said I do wish that the vintage computer market would get as much support as the vintage gaming market has. I always thought a great retro-system would be a multi-clock Intel Quark based unit with a clicky keyboard and trackball in the same box, that has XT-IDE and all that built right into it. Just clock it down for XT speeds, and up for Pentium speeds, after all, someone recently told me it basically is just a really fast 486 with modern features tacked onto it.

In my opinion these old OEM PCs are even more interesting than the generic stuff. Though they sometimes use proprietary parts, memory modules or even worse proprietary software to set up, they are usually a really good choce for retro computing. Quality of the OEM machines build by IBM, hp, Dell and others is usually very high, as the systems sold for higher prices than the generic stuff. Old power supplies are usually easy to service or to repair as they are mostly only single layer PCB and not much voodoo in the schematics. Speaking from experience with lots of IBM PS/2s, some older Compaq Deskpros and hp Vectras in the collection.

Baoran wrote:

Is there any point in buying 80s oem pc that doesn't have standard psu and even the power connector on the motherboard isn't standard AT?

For collecting: yes. For using: no. Since when using, components will get bad and you won't find replacement parts easily, if at all.

CkRtech wrote on 2018-03-21, 22:50:

You could probably rebuild the PSU if you had to. I don't know what sort of ICs they use in it, but it is possible drop-in replacements are available for those as well. I imagine there is a possibility that others have done the detective work already, but the pool of possibilities of that at vogons is rather smaller as I believe the average age here is dropping.

I do know that the line suppression cap on the larger, sideswitch PSUs for some of the IBMs tended to blow up. Only thing I have is a Kingpao PSU, and I haven't used it for any projects (yet).

yes i have all the raw material to build a pc but would like a little input please!!

Baoran wrote on 2018-03-21, 22:37:

I mean pc using something like this:

hp-0950-2035-power-supply-for-hp-vectra-4.10__60031.1490276670.jpg

i have one of theses..🤣

i am attempting to build a pc..i have the options of Gateway,Dell,HP, towers and parts,,For some reason the gateway will power on but no connection to my screen will come on..the monitor does work..i have all the party for this task but i get stumped or held up because of minor issues and troubleshooting..any advice or tiips would be great..i would be willing to take pics!!