Reviving the 1984 IBM 5155 PC - How Hard Can It Be?

[@Sheevlord]

Tantalum caps. I knew it. Those things like to fail with a short. And if a power rail is shorted the power supply protection kicks in and shuts it down. It's best to replace all of them - even the ones that test OK.

[@JanCumps]

Catching the actual moment that the magic smoke escapes is a Win! Most of the time it happens off-camera :)

[@a531016]

That's not how it felt at the time...

[@retromobs6018]

I am still swearing at the person who designed the PSU assembly.

[@niino4329]

Likely one or more shorted tantalum caps on one of the boards.

[@Chriva]

Ah, tantrum caps. The bane of every retro tinkerers' life. Those fellas really got to go, all of them. You risk blowing traces if you try to power through.

[@MrGtagangster]

Three words, Adrian's Digital Basement. Watch him, had repaired several 5150 and 5160.

[@james5583]

Great to see a video of this old computer :D do you think I should get a complete list of the components to change? 🙏 Regards

[@MAYERMAKES]

i see you are a man of culture rocking a D3300 and the kit lens...that camera is still my favourite with a better lens.

[@Otakunopodcast]

Some power supplies require a load on them, otherwise they shut themselves down for protection. I usually keep an old defective hard drive (defective as in you can't use it with a computer because it has read errors, etc. but the motors still spin up) to act as a "dummy load" when testing psu's, in case they exhibit this behavior.

[@ghosthuntergr]

tantalum caps on the mb especially on the -12 line and on the cga.

[@dalefowler4536]

Wearing jewelry while working on electronic repairs is a no no

[@sprybug]

Adrian's Digital Basement has fixed up some 5150 and 5160 boards and quite often it's those old tantalum caps that fail and short out over time. Even the video board has them. More than likely your failure points. Also, from my experience, most power supplies need a load on it to really operate, so if you're just testing a power supply on its own, probably a good idea to hook up something kinda beefy to it, like an old MFM hard drive that you don't care if it gets destroyed for example.

[@richgolfs]

I thought only the PC ATs required the dummy loads we didn’t have hard drive installed.

[@winstonsmith478]

A simple test of which caps were actually bad would be interesting and enlightening.

[@a531016]

I'll see what I can do!

[@MAYERMAKES]

holy smokes that is one of the grails!

[@dennissmith8199]

Like others have already stated, the tantalum caps on the motherboard should all be replaced, they do not age well. I know that fron experience will a few IBM 5150s and 5260s.

[@Sammmmmmmm617]

Can you help me fix my IBM 5155? I have retrace lines on my screen and I have no idea how to fix it.

[@muffenme]

use a power supply tester to see if you're getting proper voltage output without any other tool.

[@MrGtagangster]

Another note, tantalum caps DON'T age well, are almost always the point of failure. Probably why you smelled something in the first place.

[@SimonMordue]

I have a question. I have found one these bad boys on ebay. It would be perfect as a prop in a sizzle reel I am putting together for a sci-fi TV show I am dveloping. It's ultra-low budget, but I have a ton of ideas! Do you know if I can feed exterior video to the screen from say... a SONY Handycam... with the aid of some rewiring. You seem very knowledgeable and I am clueless when it comes to the internal workings of computers. I would be grateful for any help you can provide. Thank you.

[@ironmaiden5658]

Thats a shame.

[@K5smold]

Haha I have that exact same Klein tools DMM😁

[@Mkilbride2599]

El Psy Kongroo

[@horizon42q]

I have one in storage

[@Sammmmmmmm617]

Do you know how to fix retrace lines on the monitor? That's one of the problems I have with my 5155.

[@brianmicky7596]

Hi keep talking the tablets

[@typedeaf]

Nice try!

[@StevenOBrien]

You know that we can hear the "AudioJungle" watermarks on your intro music, right? A big, supposedly reputable channel like you can't be bothered to pay $20 for your theme music, or draw from the huge amount of Creative Commons music in existence instead of just stealing it from someone? What is wrong with you?