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TTX/X2 power-on power-off issue with motherboard

Cereth

Cereth

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Hey there, I'm revisiting an old problem I had back when I used to buy up a lot of these, and was too dumb to do any repairs or anything. Over the years I've collected a lot of TTX/TTX2 motherboards that power on and off every second when you plug them into power. Jumping the power pin quickly/repeatedly, they will fully power on, but won't do anything. What I'd like to do is identify the problem and fix it/have them fixed if possible, get them put back together into complete working units and/or pass them on to someone who can. Parts have been sitting around collecting dust for a long time, and I'd like to see them finally go to good use.
 
I think I have this exact same issue. Trying to figure it out. Replaced PSU and recapped my motherboard and still having the power cycle issue. Did you ever make any further progress on this @Cereth?
 
Murray said:
The moment i put this unit back in the case and screwed it all back together, the issue stopped and it worked properly again...
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All the screw holes are basically ground posts. I wonder if that has anything to do with it?
 
I've got a TTX2 and a TTX1 that exhibit this behaviour as well. I haven't had time to troubleshoot either of them. really strange that de-casing and re-casing would solve it though.
 
I haven’t tried swapping CPUs, this is probably a year or two from now project for me
 
Yeah I would be surprised that just re-casing the board would work, but also am jealous if that fixed it. I have tried everything I can think of and still no luck...
  • Pulled all peripherals
  • Unplugged all fans
  • Pulled RAM
  • Pulled CPU
  • Recapped all electrolytic caps
  • Re-cased
  • Swapped PSU
  • Pulled CMOS battery to reset CMOS
I fear there is something else faulty on the motherboard and based on the number of people that seem to have this issue it may be a common issue. I am determine to track it down, but definitely a puzzler.
 
I feel like the board is probably faulty, maybe a surface mount IC failing somewhere? I ran into this issue once on one of the boards I had. Oddly, putting in a slower CPU solved the problem (it had a Core 2 Duo, I downgraded it to a Celeron). Tried everything short of recapping.
 
kazuo said:
I feel like the board is probably faulty, maybe a surface mount IC failing somewhere? I ran into this issue once on one of the boards I had. Oddly, putting in a slower CPU solved the problem (it had a Core 2 Duo, I downgraded it to a Celeron). Tried everything short of recapping.
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Agree, I think the issue is on the motherboard. Hard to test with the power cycling all the time so not really sure where to start poking around.

I did try to boot even without the CPU, and no dice, so don't think the slower CPU will solve my issue. My understanding is that it would at least power on without the CPU if the CPU was causing a short.
 
Ah, yes, if it won't even POST after all of that, it's probably dead. :( My issue was that it would POST, work fine for a few minutes, and then randomly reset/power cycle itself.
 
I’ve had this issue with an X2 I got recently. While I haven’t solved it, i have narrowed it down. Unplugging the wire harness right near the cpu (12v I believe?) and turning it on is the first time it’s stayed on and not power cycled.

My tech/repair skills are weak on pc stuff and I’m learning as I go.

To get to the point I’m at, I removed video card, jvs, and ram. I replaced case fan and cpu fan, cleaned cpu heat sink and applied new thermal paste.

Also removed it from case.
So it currently will stay on and not power cycle but it is sitting outside it’s case with only power supply, mobo and cpu. With that one wire harness by the cpu disconnected.

I would never have thought about trying it with that harness disconnected, I was looking up power supply info and saw a post (here I believe) saying that was a common issue for pc’s so I gave it a shot. Next step I assume is tracking the short. I know the fundamentals of a volt meter, but if the short is on/in the mother board itself that will probably be beyond my skills.
Any advice is welcome
 
Neo Chosen One said:
Any advice is welcome
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Two suggestions:
1) Plug back in the peripherals like JVS, graphics card, RAM, etc, and see if one is causing the short.
2) Check the 1000uF caps. How do the caps look around the CPU and the 12V rail that is from the ATX connector across the back of the board? It seems often that people are able to address a 12V rail short with a recap of the 1000uF caps.
 
I had an X3 exhibiting this exact behavior and it was due to a faulty GPU fan. System would kick on, only one of two GPU fans worked, so when there was no pulse on that sensor, the system shuts off, powers on for a moment, rinse and repeat

A new GPU solved the issue.

Edit: basically, check any 3 wire fans / fans with sense wire as they can cause this.
 
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