VOGONS


IBM 5150 & 5160 CapKits

Topic actions

First post, by Retronaut

User metadata
Rank Newbie
Rank
Newbie

Hey, I have a collection of 1 IBM 5150 and 2x 5160 which I intend to renovate soon. I have heard that the tantalum caps used on these machines tend to have already blown, or be close to dying. So... I think it may be an idea to just recap the whole shebang? Opinions please?

If I do go ahead with this, does anyoneone know of a place, ideally in the UK which sells capkits for these machines. PSU's included?

Cheers

Chris

Chris Thomas
aka Retronaut @ https://www.youtube.com/@RetronautTech
Support me @ patreon.com/RetronautTech

Reply 1 of 2, by the3dfxdude

User metadata
Rank Oldbie
Rank
Oldbie

The issue is that for certain manufacturing runs for tantulums, they tend to blow easier after sitting for a while and then powering it up. This was seen in the beginning, with the 5150 and other systems of the time, and so true for any that have sat for so much time now. So some of the boards are this way, but not all. I've not seen any tantulums blow on any of my boards, including IBM. But I have, and still do power this stuff up pretty regularly.

The other failure pattern is the tantulum fail short, and so in this case, not blow and still be bad. They may show no visible reason to be bad. I have not seen one go short yet.

Other than that, tantulums are pretty reliable. Electrolytics quality has varied alot, but maybe not going to be much issue either. And there are other parts that can go boom. The PC/XT are very reliable, well made systems, well at least the system boards. And the failure cases are well documented:
https://www.minuszerodegrees.net/vcf_motherbo … ure_history.htm

Personally, I would study these machines and learn how to gently test them, step by step, identify what really needs to be fixed. The PC/XT has alot of good information on the net on how to do this. Plopping a board down and hooking up power and putting it on video when flipping the switch is a way to get clicks, but not actually the way things are. And recap everything practices again, while can be a thing if you know which cases are prone to be an issue, but really not always a thing you should do until you know exactly the reasons and how to go about it.

The power supplies in the IBM PC/XT, again are usually pretty good. I'd look it over and test them.

I only say this rather to not have you waste your time getting recommendation on just do or don't do, but to collect the info and do exactly what is needed.

There really isn't a kit needed for doing this, but if you head over to minuszerodegrees, it will have pretty much everything you need to figure out replacing a cap. Also note that not all the cap looking things are tantulum, there are also ceramic, which do not need replacing almost ever. Read this concerning the tantulums.
https://www.minuszerodegrees.net/failure.htm

Reply 2 of 2, by Retronaut

User metadata
Rank Newbie
Rank
Newbie
the3dfxdude wrote on 2025-12-01, 23:28:

There really isn't a kit needed for doing this, but if you head over to minuszerodegrees, it will have pretty much everything you need to figure out replacing a cap. Also note that not all the cap looking things are tantulum, there are also ceramic, which do not need replacing almost ever. Read this concerning the tantulums.
https://www.minuszerodegrees.net/failure.htm

Good points, I had a look at the minuszero failures page, VERY useful. I have to say, Tantalum caps do seem to fail a LOT, and some RAM etc. Cap C56 in particular seems to be a VERY common failure.

Chris Thomas
aka Retronaut @ https://www.youtube.com/@RetronautTech
Support me @ patreon.com/RetronautTech