IBM Thinkcentre S50 TYPE: 8086

[PCBONEZ]

Re: IBM Thinkcentre S50 TYPE: 8086

Yes, a good cap should show charge and discharge on an ohm meter.
If it's a solid number then there is a parallel path or it's open or shorted.

And, some close in pics would be good about now. [hint, hint]
.

[momaka]

Re: IBM Thinkcentre S50 TYPE: 8086

No thoughts on this whatsoever? Anyone?

I don't know, but the resistance looks fine to me - reason I say this is because voltage on Vcc_agp is low, so 40 Ohms doesn't sound like a lot for that. I measured resistance on what I think is Vcc_agp on a Jetway socket 462 motherboard with a video card installed in the AGP slot and got a reading of ~25 Ohms. There were 2 other MOSFETs in the AGP area, and they read around 100 Ohms to ground. Not sure if that helps you with anything.

[jimmy274]

Re: IBM Thinkcentre S50 TYPE: 8086

Well, I just realized that vcc_ddr is fine - solid 2.6v with resistance of 30 ohms. So it might be that vcc-agp has no short - it's just that power is not delivered to it (0 volts), which could mean that powermos is fried. I need to check the gate voltage to know for sure, though (and that's probably pulse width modulated, so I'll need my oscilloscope).
Will post back when I'm done. Thanks momaka.

EDIT: If I'm not mistaken, I think that vcc_agp should be around 1.5v. Someone correct me if I am.

[spiros123]

Re: IBM Thinkcentre S50 TYPE: 8086

Hi,

I had the same problem with an IBM 8086 where the fans just turn on and nothing happens. Originally it just had a bad power supply, switched it with another one and that fixed the problem. But when I put in a new power supply the thing wouldn't turn boot, just the fans and that's it.

I had a student open it up and remove the CPU heatsink and there was a loose low profile resistor (that what a friend told me they're called). I have ZERO electronics experience with soldering but was able to solder it and it worked. (Reapply thermal paste to the CPU before putting on the heatsink. It has worked without issue for the past 2 week. It also has had a full 2 GB ram installed.

Unfortunately, I now have the same problem with another computer where only the fans turn on. It did have Blue screen of death, JUST before that. I'll tell you what happens when I fix it.

I do agree that these small cases heat up too much. I'm a classroom teacher and have 12 of there in my room. The one I use regularly reports high temps (50C) with Speed Fan 4. I have not been able to get the fans to stay on high but they are variable on they're own. I'm looking at getting a PCI slot fan and test it out on one computer before doing it on any others.

-spiros