I recently had a PSU fail and am having problems getting the replacement unit I bought to work. I was hoping someone might have some suggestions for me. Any help is greatly appreciated!

My motherboard is an Abit KV7 (socket A). I purchased a Thermaltake TR2 RX 550W PSU to replace the failed unit (older Antec 350W). When I power-up the system, the lights come on and the fans turn but I get no video output or any of the usual beeps that I get when the mobo powers up (also no error beeps). It's as if the CPU is not running

Is there any reason why the Thermaltake PSU should not work with my KV7? The new PSU has a 24 pin connector but it was my understanding that this will work fine with a 20 pin mobo. Can someone confirm this? Also, the new PSU does not have the 3 pin fan signal connector that the original unit did but I assume that this should not cause the problems I am having.

I've tried a different video card with no luck (didn't expect it to) and am concerned that the PSU failure took the mobo or CPU with it. The old unit failed after powering down. The system was working fine when shut down but would not power up again -- no lights, no fans, no beeps (also no "bad" sounds -- pops, cracks, sizzles, etc.).

Is there anything I am overlooking? Again any thoughts/ideas/suggestions appreciated!

Thanks.

So many things can go wrong when a PSU dies, so its very hard to determine what else was affected.

Only thing I can think of, is to look at the RAM dimm pins to see if there is any signs of burnt or blackened gold leads/pins.

Try swapping ram and use 1 stick at a time.

Did you plug the 4pin CPU 12v ATX connecter in?

When a PSU dies it can often take pretty much every and anything with it.
Thats why people use such overkill psu's.

Those connectors should all work fine, did u remember to plug in the CPU power??? (4-8 pins, will be near the cpu)

You pretty much have to isolate every individual component. Its often the mobo that dies tho, so.... good luck!!!

During my early years of experimenting with cheap crappy PSU's I have had more than one PSU failure.
Once with the effect of rendering my whole system unusable.
Other times killing parts of the system.
That's why I buy PCPower PSU's now.

Thanks for all the suggestions. System is working now...turns out it was a rather odd issue. In the process of testing the new PSU for correct outputs as well as checking the DIMMs I ended up disconnecting the USB expansion slot. It appears that this was the culprit -- if I connect it the system doesn't boot if I disconnect everything works ok. Which is really odd because I had no usb devices plugged into it. Oh well. System is working now and I don't need the extra 2 usb ports so all is good. Thanks again for the help!