boot problems, possible hd4850 issue

Hello,

I am having a very odd problem, my computer is very temperamental when booting. Usually when I turn it on, the cd rom flashes, fans come on, I can hear the hdd fire up - but the computer doesn't beep and post. But if I turn it off and on a number of time it eventually does boot.

I originally thought it was the motherboard Gigabyte GA-P35-S3G and so returned it to ebuyer where I brought it from, however they found nothing wrong with it and returned it to me.

When I installed the board again it posted first time, and I noticed the red LED on the bottom of my hd4850 goes off when it posts. I originally thought this LED was a power indication LED as when I opened my computer first time it wasn't posting, this light would remain lit. I am now thinking this is probably a diagnostic LED and it might tell me the possible cause of my problems. After googling it seems the card has two diagnostic LEDs, one for 12v failure and one for temperature failure. But I am unable to find any information as to the location of these two LEDs.

Can anyone help me identify the LED that is being lit? It is near the top edge towards the rear of the card.

What PSU are you using??

Zalman heatpipe, 500w, (ZM500-HP) should be able to handle it. Have got a 2 year warranty on it tho so if it is to blame, not the end of the world.

After much googling I have found the locations of the LEDs, as it turns out, both are constantly lit... has anyone got any suggestions?

That means that the card doesnt have enough power to boot up. Mine has dont it before when I have been messing about with volt modding etc.

can you lay your hand on another PSU to try out?

Your PSU
http://www.quietpc.com/gb-en-gbp/pro...plies/zmx00-hp

It looks like it should have enough power. Have you made sure the modular PCI-E socket is plugged in properly as that would also cause a failure.

yea I recently tried the modular pci-e connector for the graphics card instead of the one that uses the mail bulk of cables (ATX, CPU) but the same thing happened. My friend has got a psu he said I could borrow and another friend has a hd3470 I can borrow - so hopefully I can then identify which is as fault.

Kinda hoping its the PSU as I've modified the heatsink on the GPU (works well, its 40 degs below standard temp) and so it means I can't send the GPU back.