1986 "XT 286" PC Power Supply Gets A Modern Upgrade! - Restoration Part 4

[@DaveVelociraptor]

Hello Adrian!

[@richardestes6499]

Totally didn't expect that nod to Adrian Black. Hilarious moment

[@Stuart-AJC]

An IBM XT286 was my first PC at work. It was mostly used to run a 3270 card to connect to an IBM mainframe, and for WordPerfect. Compared to dumb 3270 terminals and typewriters or dedicated word processor (SuperBrain), it was a revolution in our company

[@JVHShack]

If the lack of -5v becomes an issue, There is a way around that without redoing the PSU again. Since KZbin won't allow links in the comments, just search for "Voltage Blaster" which was created in a collaboration between Necroware and Phil's Computer Lab, both of KZbin fame.

[@ctrlaltrees]

Ah yes, I had someone suggest this to me on the Point of Sale PC video as well. Maybe it was you? Although I don't *need* it perhaps I should get my hands on one for a video anyway just to see how it works...

[@nicchester7519]

Great stuff! I'm in the middle of doing something very similar with my IBM 5155 Portable PC. Initially the original power supply worked, but there was far too much ripple and noise on the 5V line for the motherboard to work, and a recap solved that... until the whole PSU died completely after a few hours of use. Now, in principle I like to keep things as original as possible but this is a great mod for people who really enjoy these machines and need them to be somewhat reliable. By the way, if you ever find you need the -5V (I have a few expansion cards that do), a 7905 voltage regulator with a couple of filter caps can step down the -12V line, and in fact I believe that was the solution employed in the original XT power supply.

[@garywilkinson5887]

I’m following along with your videos and upgrading my 5162. I’m in the process of replacing the internals of the PSU with a brand new AT PSU from Antec, which makes things a lot simpler.

[@garywilkinson5887]

The bit where you mentioned the only way to open a security screw is to use a dremel made me laugh. A gentle dig at another KZbinr 😀

[@ctrlaltrees]

I don't know who you could possibly mean 😉

[@p_mouse8676]

Btw those "blue capacitors " on the IEC connector could also be MOV's. Thumbs up for doing the sensible thing by replacing the PSU as well as replacing the old caps. 👍🏻I keep telling people that one day or another these things WILL go bad. When that happens they often drag many things with them. Often parts that are not available anymore. The -5V can always be made with a DC/DC positive to negative converter.

[@Trusteft]

I did not see that coming. The skinning of the newer PSU to insert the guts inside the old PC. Nicely done. Not that I know anything about PSUs guts. Cool video.

[@blackterminal]

I like things kept original where possible but I see the benefits

[@Epictronics1]

Looking forward to part five :)

[@msthalamus2172]

I don't think I'd have the patience to solder all those wires together one by one. I admire your dedication! :D

[@opp31337]

A company called Athena Power still makes a 300 watt AT power supply, the AP-AT30, for legacy and industrial systems... this might be a better alternative than using the ATX supply. I picked one up for testing old systems.

[@pete8475]

1:37 - omg, frigging 8bit guy. 🤣

[@leesmithsworkshop]

I am so glad you didn't turn it on with a paper clip.

[@andygozzo72]

hm,, yeah ...😁 **bang**

[@RetroSegaDev]

Bravo! Great work Rees!

[@ctrlaltrees]

Thanks!

[@GameRetro]

Very nice! Gives me some ideas on things to try with my IBM Model M.

[@RetrogradeScene]

Nice keeping the original wires! great job its a loverly machine. I was getting distracted watching youtube in the background though!!!

[@ctrlaltrees]

Haha, I always have a nice long "Watch Later" list to work my way through as I'm working on this stuff 😁

[@smarseille7422]

I agree on the fact PSU should not be considered being part of keeping hardware original. Especially if the future of the PSU is unsure and cannot be maintained to keep it reliable enough not to destroy your hardware. But I surely love how original state you kept the housing! Also the long boot before display scared me xD

[@lasskinn474]

Well.. It is a part of keeping it original but not a part anyone really gives a toss about, it's not like we're having pebble beach exhibitions with prizes with judges consdering if the screws look like touched after the factory. Mods that keep them usable for running the software are a-ok

[@ctrlaltrees]

Classic Computer Concours... Now there's an idea

[@andygozzo72]

no reason why an old psu cant still work reliably.... these ones were made well before the capacitor plague issue, and modern capacitors dont seem to last as long, anyway...

[@nickwallette6201]

@@andygozzo72 Caps and fans are the parts that usually fail. The old ones are stout, but I replace them anyway. The Panasonic / Nichicon / Rubycon caps, and Sanyo Denki fans I use are likely to last another 20 years. At which point, if _anything_ in the computer still works, I'll consider that a win. :-) The next likely thing to fail are PSU transistors and diodes, since they're high-power parts that live a relatively rough life. In MOST cases, they can (and will) fail quietly, without a lot of fuss. It'll just stop working. Or perhaps trip a protection circuit or blow a fuse. It's not inconceivable that something will fail and take out stuff downstream, but that's _always_ a risk -- even with PSUs that are half as old, or even brand new. You can't insure against that. May as well enjoy it while you can.

[@andygozzo72]

@@nickwallette6201 i havent...yet...come across a pre 2000s motherboard with bad caps, all the ones i've seen have been 2000s era...as for psus, similar, apart from few odd 'old' ones with dried up caps, but not surprising as theyre fairly heavily stressed

[@BatteryPoweredBricks]

Wow, that's actually kind of genius to take the internals from a modern power supply and put them in the original PSU. I probably would have just jankely set the modern PSU inside and held it in place with zip ties or something 😂

[@Yesterzine]

It’s always mad to me how those mobos are so massively simple but also massively complex to do very little.

[@ctrlaltrees]

I think that sums it up perfectly 😁

[@nickwallette6201]

This is a great visual reminder of what "integrated circuits" actually means. So much of that board got integrated into a single chip -- the "chipset." And a bunch of RAM chips moved into their own pluggable modules, and so on. The motherboard, for a very short while, became little more than a backplane. And then vendors started integrating more previously card-bound components into the motherboard again. :-)

[@GarthBeagle]

Nicely done!

[@superhik336]

what model part number is ATX power supply you used for this video? it would be good to know, looks like a good fit.

[@chris_hertford]

Most PSUs I've worked on have a plastic sheet for added insulation between the PCB and the metal case. I didn't notice if this had one?

[@ctrlaltrees]

Yes it did, I fitted the one from the new PSU but that shot didn't make the final cut. I probably should have mentioned it 🙂

[@andygozzo72]

personally i'd consider the old psu more reliable than many modern ones, especially cheapo ones, as long as you make sure any RIFA branded class x and y suppressor caps are replaced, these are notorious for the epoxy casing splitting and eventually exploding... if worried about the voltage rocketing and destroying parts, should be possible to rig up a voltage clamp or crowbar trip, it may have one internally anyway...

[@douro20]

Zenith, eh? I thought they went to Astec supplies at this point. I have a supply out of a late production 5160 which was made by Astec, and it has an AVR and active PFC (yes, active PFC in 1986).

[@AncientElectronics]

I have a similar issue with my IBM AT, the PSU dies and because of the form factor I haven't been able to source a replacement. I may need to look into trying something similar.

[@andygozzo72]

the original may be repairable...

[@rizmark5522]

wow great channel, I subscribed, great goodies and tech

[@robbyxp1]

The lighter was a homage to Jan Beta right? The rest of them you actually used a heat gun on ;-)

[@yogibear2k220]

Because what I know about electronics you could write on a match head, I will ask a stupid question. As the new power supply fitted inside the old power supply case, could you of not just left the new power supply as was and just made a cable up from the old PSU input plugged into the new PSU input if that makes any sense, rather than strippin g down the new power supply. Good video, though. I do like these old machines. They looked amazing. I would love to house my PC in one of those cases.

[@Stjaernljus]

One thing to look out for when doing this is that the modern PSU has enough umpf on the 5V line as modern PSUs put most of it on 12V.

[@djcsdy2]

I have a BBC Micro with an internal PSU that has released its magic smoke. I'm tempted to just take out the whole PSU and replace it with a modern external PSU, possibly even a USB PSU, but I can't decide if the retro community would hate me forever if I did such a thing. To me keeping the PSU original doesn't matter but some people go to so much trouble to repair them. I find it baffling. Especially when PSUs from the 80s are crazy inefficient.

[@andygozzo72]

repair kits are available, most common cause of smoke is not the psu circuit itself but the RIFA branded mains suppressor capacitors, they split, let moisture in and eventually explode, replace those 2, plus a 220uf 25v in the primary circuit and then will usually be ok, some like to replace all electrolytic caps, as they've been known to leak..as for inefficient, if it the usual switching thing(i assume, early ones were 'linear') , theyre not too bad,

[@BollingHolt]

Very nice! Jealous ;)