Thread: M2-ATX crowbar circuit?

Originally Posted by deanthom

Well, I ordered a M2-ATX and then read all the stories about them burning up and taking the PC with it That's rather annoying to say the least! I am thinking of building a crowbar circuit on each of the rails to protect the mobo and stuff, anyone else done this? Basically a crowbar is a circuit that triggers when the voltage gets too high and shorts out that rail, thus blowing a fuse and preventing the spike getting any further. See http://www.radio-electronics.com/inf...ge_crowbar.php

This seems like a good idea to me, I don't want some poorly designed power supply blowing the crap out of all my expensive stuff just because the designers were too stupid/cheap to put in overvoltage/overcurrent protection (which it part of the ATX spec i believe). Or am I wasting my time with that?

Thanks!

It is not a bad idea to add more protection to anything. However, I believe any crowbar circuit will have a voltage drop, whcih could be problematic for your MB.

And while no one wants to admit it here, I believe all those broken motherboards are cases when the M2s specs are exceeded. Make sure your system is under the M2 specs, and you should be fine.

Michael

A crowbar circuit should not cause any voltage drop, it is totally inactive until the voltage reaches it's trigger point. I don't see how the circuit I linked to could cause any voltage drop.

I have measured the actual current usage of my system with an ammeter on each rail, and come in under the M2's specs, so I should be OK. However, it still un-nerves me that it has no protection circuits should it's regulation fail for some reason.

Dean

If you are going to go the route of the M2-ATX, I would reccomend whatever protection you can get. I just lost a processor and motherboard because of a self-destructing M2.

Originally Posted by EvilLawnGnome

If you are going to go the route of the M2-ATX, I would reccomend whatever protection you can get. I just lost a processor and motherboard because of a self-destructing M2.

Sorry to hear that man, that's not what you want to happen. I'm kind of regretting buying the M2 now. Out of curiosity, what kind of setup were you powering with it?

Too much.
I was running a M-ATX board, with a Mobile Athlon 64 3000+.
512mb of Mushkin DDR.
Soundblaster Audigy.
Dlink Wireless-G card.
Liliput 7" touchscreen and a 4 port usb hub (all powered by the m2).
and 4 fans.

I didn't take into account how much power the screen would draw, and I guess it just sent it over the edge. Thankfully it was only the MOBO and the CPU that took the hit.

I ended up making a simple overvoltage and overcurrent protection circuit for my M2 in an attempt to save my PC if for some reason the M2 feels like having a BBQ. You can see it in this post in my worklog. I just can't trust a power supply with no fail-safes! What were they thinking!