Zeugitai wrote on 2025-02-05, 02:25:

I pulled a previously working MPC PC from several years storage, replaced the CMOS battery, cleaned the feet of the RAM, started, set system time, Win XP splash screen came up as O/S booted, then, dead like a fuse blown, but power light still illuminated. After a moment, able to restart to the same effect. I was able to boot into safe mode, but not normally into the O/S. I suspected PSU and power cord, but the green light never goes out. Does this ring any bells for anyone?

The fact that you can boot into safe mode (and I'm assuming it's not dying shortly after that) but not into "full OS",
suggests to me that it's a software problem - or quite possibly a hardware problem that doesn't
cause problems until the full-bore OS is trying to start.

Do you know for sure that it was fully working when put into storage?

I don't really recall just what you can do in "XP safe mode" - do you have a way to run a memory test
and also verify that all sectors on the HD are readable?
- Failing that, perhaps you could boot DOS (floppy or flash-disk) and run memory/disk checks from there!

Dave ::: https://dunfield.themindfactory.com ::: "Daves Old Computers"->Personal

Thanks, Dave. I confess to having forgotten my DOS although I have the book somewhere. The PC sits stable in safe mode. I didn't know what to do with command line. I just let it tread water to see if it would stop. It didn't. So I tried again and it failed again during o/s boot. The computer was working fine when stored, but its been in the basement at least five years. The way it goes instantly still and silent isn't something I've ever seen before. Usually there are sounds when winding down. This is just sudden silence.

I was tired, bleary-eyed when this happened and it threw me. I do have diagnostic tools and diskettes stored somewhere in the basement for at least 15 or 20 years. I'll find them tomorrow. I'm rusty for sure! 😄

Zeugitai wrote on 2025-02-05, 04:42:

Thanks, Dave. I confess to having forgotten my DOS although I have the book somewhere. The PC sits stable in safe mode. I didn't know what to do with command line. I just let it tread water to see if it would stop. It didn't. So I tried again and it failed again during o/s boot. The computer was working fine when stored, but its been in the basement at least five years. The way it goes instantly still and silent isn't something I've ever seen before. Usually there are sounds when winding down. This is just sudden silence.

There is a good memory-test called MEMTST86 which runs stand-alone, not even under DOS...
(it's it's own boot floppy)

There are tools to scan drives for errors - I think DOS has "scandisk" - but I don't know if it requires a FAT filesystem
(XP uses NTFS), of if there are modes where it can just scan the raw sectors to see if they are readable (and
either way - I *wouldn't* let it try to "repair" anything ) ... I'm sure other participants can recommend more modern
and better hard disk checking tools.

When you say "goes completely silent" - do you mean not even the sound of hard drive spinning or
power-supply/CPU fans? - is this ATX... (which would let the OS power it completely off - but in that
case, no lights should remain ON - when ATX is powered off, only one very low-power rail remains active
to provide power to "power on detect" circuits .. I've seen systems with a LED powered from this which
is on whenever the system is plugged in - and systems which don't completely power-down and
turn on a LED when they are "sleeping" - but I'd think you would know if this system did this previously)

Dave ::: https://dunfield.themindfactory.com ::: "Daves Old Computers"->Personal

I'm afraid I'm not getting out of this one easily. I booted into the o/s okay but in thirty seconds, poof. Following this, when powered on, only the fan runs. No POST. I removed sound card and GPU. Still only fan, no POST. Recleaned RAM contacts with alcohol pads. Fan, yes; POST, no. Removed heat sink. Thermal paste still good, moist. Replaced it anyway. No POST. Rrmoved half the RAM. No POST. This M/B is Intel D915GRV. Looks fine. No leaky caps.

MPC Client Pro 365. Intel 915GRV. LGA775 socket. P4 3.6 GHz. Made in 2006, I think. I got is cheaply, used & abused. I replaced CPU, PSU, added Ge Force 610 GPU, and had XP sp3 running in 2014. I think the last time it was run was in 2019.

Zeugitai wrote on 2025-02-05, 19:47:

I'm afraid I'm not getting out of this one easily. I booted into the o/s okay but in thirty seconds, poof. Following this, when powered on, only the fan runs. No POST. I removed sound card and GPU. Still only fan, no POST. Recleaned RAM contacts with alcohol pads. Fan, yes; POST, no. Removed heat sink. Thermal paste still good, moist. Replaced it anyway. No POST. Rrmoved half the RAM. No POST. This M/B is Intel D915GRV. Looks fine. No leaky caps.

So it's not running at all now - even after being off for a good long while?

Do you have a speaker connected? Does it beep at all.
With no RAM - does it beep a fatal error code?

Just trying ti figure out if the processor is running at all

Dave ::: https://dunfield.themindfactory.com ::: "Daves Old Computers"->Personal

No beeps. Nothing but the fan now. I have another P4 i can swap in tomorrow. I just found a system board manual. I spent some time today cleaning all the contacts. Didn't get far.

I see you've already replaced the PSU .. are you absolutely sure this one is good.
I just spend a couple days tracking down a fault in an older P4 system I was running
DOS on that got unreliably - accessing hard drive would sometimes kill it - sometimes
network traffic.

As it was an "open" system, I thought some dust/crap might have gotten into/onto the board,
dismounted it from the "homemade case" (really a piece of wood), gave it a good cleaning with
compressed air, tapped it upside down on my workbench to knock out anything that might
have collected, gave everything a good brushing - then set it up on same workbench (just sitting
on a book to raise it) and everything worked perfectly - so thinking I had found/fixed what was wrong,
I reassembled it back into it's home - and ... still was failing a lot ...

Turns out the one piece I hadn't unmounted and used on the workbench was the PSU, set it all back up
there - confirmed that everything worked, then moved the original PSU over - and it started failing....
Weird, PSU didn't have any visible failures and seemed to work OK (power rails measured good etc.) -
system didn't draw a lot of power (only add-in card was a NIC) - but changing the PSU made it all work
reliably again.

I'm going to spend some time with some big/heavy load resistors I keep for this
purpose, and an oscilloscope - to see what it does under various loads.

Maybe your problem is something similar!

Dave ::: https://dunfield.themindfactory.com ::: "Daves Old Computers"->Personal

Thanks. You're confirming my suspicions. I'm going to check the CPU today. Didn't know they could fail from age and disuse, but what doesn't?

Zeugitai wrote on 2025-02-06, 14:43:

Thanks. You're confirming my suspicions. I'm going to check the CPU today. Didn't know they could fail from age and disuse, but what doesn't?

I wouldn't expect any IC to fail from age and disuse (except possible EPROM / FLASH)

Earlier this year (well - I guess late last year), I fired up my Altair - a computer from 1975....
Original 8080 CPU - also from 1975
I used it a lot up till early/mid 90's and it hasn't seen much use at all since 2000+
Still fired up and ran perfectly.

I've got systems from before that.... and up till last year I had very early PC (like original IBM 5150)
I think the oldest I have now is a P200MMX - still going strong!

and I've got a TRS-80 Model-100 (one of the earliest truly portable computers)
from 1983 sitting here on the desk beside me (and I just switched it on - working well)

Dave ::: https://dunfield.themindfactory.com ::: "Daves Old Computers"->Personal

Swapped CPU to no effect. Cooling fan never falters. Measured steady 12v. on motherboard (at exhaust fan pins). The psu was a new unit in 2014 and the system hasn't been run more than a few hours since I got it. Two days ago, it faltered on startup, then something failed so that now there is no activity but the cooling fan responding: No POST, no beeps. I'm out of ideas.

Zeugitai wrote on 2025-02-06, 20:36:

Swapped CPU to no effect. Cooling fan never falters. Measured steady 12v. on motherboard (at exhaust fan pins). The psu was a new unit in 2014 and the system hasn't been run more than a few hours since I got it. Two days ago, it faltered on startup, then something failed so that now there is no activity but the cooling fan responding: No POST, no beeps. I'm out of ideas.

What about other power-rails? 12v is probably the least needed to get POST...
Do you have a multimeter?
Do you have a scope? Worth seeing how stable the rails are (When caps fail things can get very
unstable) If no scope, try measuring AC on DC rails - your meter should filter out the DC, but
failing that use a resonably size cap with a smallish load resistor from the meter side to ground..
Basically you want to charge the cap quicker than the meter load would (which should be very
low) once charged the meter side should be at ground level with the AC ripple passing though...
If you see any AC on the DC rails, it means they are not stable (a 5v rail with 1v ripple will show
AC ~~1v)

Do you have another (working) system with a compatible supply? Might be worth swapping
supplies to see the problem moves (be sure to verify all the rails in this supply before trying in
in a working system).

I'd leave hard drive disconnected - all you want to see is it can POST, go into setup and
be stable while you stay there.

Which reminds me.. If you've not disconnected the drive any anything else not needed to
post - try that! My system which became unreliable when the PSU was failing was still uber
good when I disconnected the HD and booted it from floppy!

Dave ::: https://dunfield.themindfactory.com ::: "Daves Old Computers"->Personal

I very much appreciate all your help. I'm defeated. I have other computers to use. This was a hobby machine got for $30 intended to remain on Win XP. It's not a great loss. I'm going to keep trying to troubleshoot it, but I won't waste any more of your time on it until and if i get some noteworthy result. Thanks again.