View Full Version : 5170 PSU Help

Matt Treck
March 29th, 2017, 02:26 PM
Hi, I've recently been fortunate enough to buy a new IBM 5170 that had never been opened from the factory. The person sold quite a few of them on eBay so I picked one up while I had the chance. I'll preface all of this by saying I'm very new to working on/with older computers so forgive me if I sound like a fool.

I did a visual inspection of everything on the board as well as part of the PSU and everything seemed to be in excellent condition. I had a good expectation that something would fry the firs time I powered it on so what happened was not a large surprise. There was about a second of humming, as if the machine was booting, and then nothing. Now about half a second after flipping the switch, the status indicator lights on the front of the PC flash for about a half a second. I cannot get the machine to do anything else. The fan on the PSU does not spin or anything.

Tomorrow I'll be taking it to a local radio shop, I know a man there that has plenty of experience working on this type of thing and he'll be excited to work on something so old but so clean. I figured I'd post here to see if anyone had any immediate suggestions as to something I might be doing wrong.

Thanks! Sorry if I left out any important information.

Matt Treck
April 7th, 2017, 02:58 PM
Just wanted to edit this, as I resolved the issue before this post was approved (I'm still a new member).

Apparently the Serial/Parallel card was causing some sort of short with the PSU. I was not aware that these older PSU's required a load in order to function at all. I plugged directly into the HDD and was able to troubleshoot my way to the card from there!

April 8th, 2017, 04:24 PM
And subsequent to that, I had suggested to the OP (via PM) that he investigate C11/C12/C21 on the card, based on our previous experience of such 10F/16V tantalum capacitors on other 51xx motherboards and cards.