Thank you for being a valued part of the CNET community. As of December 1, 2020, the forums are in read-only format. In early 2021, CNET Forums will no longer be available. We are grateful for the participation and advice you have provided to one another over the years.

Thanks,

CNET Support

General discussion

New mbo & cpu, no post, no beeps, no video

by andersonsbusiness Feb 13, 2009 1:18AM PST

Have a Dell Dimension 8400 Pentium 4 (purchased 9/2004) with a runaway CPU fan that would not boot up. Found similar issues in a forum with one poster mentioning that 9 out of 10 times the reason is a bad mbo.

Decided to rebuild and go cheap. Due to Dell?s unique mbo form factor, had to purchase a new case (mATX), and bought a Biostar G31-M7 TE 775 mATX mbo (socket 775). Swapped in the Dell 350watt psu, ram, video board, sound board, and drives. Turned on power and no POST, no beeps, and no video ? blank screen. cpu fan spins, hard drive spins, but no video and oddly enough, no indication that my USB receiver for my wireless mouse and keyboard is functioning (the receiver should light and that does not occur).

Thought maybe the P4 was bad and purchased an Intel Celeron 430-L single core (socket 775) ? same results. Swapped out the Dell psu, and replaced with a known functioning and compatible psu ? same result. Iteratively removed ram, video board, sound board, and drives ? same result. Anyone know if if is possible to POST with just psu, mbo, and cpu? How about just psu, and mbo? Does BIOS get a call from CMOS without going through cpu?

Only thing I can think of is that when I initially secured mbo to the chassis, I used washers that came with the case that appear to be insulating washers. Could I have shorted the board by doing this? Why is does mbo have to ground to the chassis, isn?t the psu fully grounded through the power cord? I have since removed the washers and the result is the same.

This is my first build and maybe I have over-looked something very elementary:
? Is my mbo and cpu incompatible? (the mbo states that it supports a Celeron 400 ? I have a Celeron 430-L)
? Is BIOS already loaded in CMOS on new mbo?s?
? Should I somehow be booting up off a disk?

Appreciate any help ? thanks!

Discussion is locked

5 Posts
- Collapse + Expand Details
- Collapse -
did you use a dell power supply
by ramarc Feb 13, 2009 5:37AM PST

some dells use a proprietary mobo power connectors that just happen to look and fit standard atx motherboards. but the pinout is different so a dell power supply may be incompatible even though it fits perfectly.

- Collapse -
Reply to ramarc
by andersonsbusiness Feb 13, 2009 6:03AM PST

Thanks ramarc, yes I initially used my Dell psu but then used another known functioning psu from a recently purchased E-machine box and had the same results; no POST, no beeps, and no video. Could I have blown something having intially used the Dell PSU?
Would you know if ram is needed for POST? I tried to POST using just a mobo, cpu, and psu, but still the same results. My ram speed is 400MHz and the mobo has a data bus speed only as low as 533MHz. I just read this:

"Incorrectly set memory timing parameters in BIOS may prevent the machine from operating at all. Some systems with intel chipsets, when presented with out-of-bounds memory timing parameters during POST, simply lock up. This happens before video or any other devices are initialized, so the machine appears totally dead. Using the jumper to clear the CMOS to default is frequently the only." Wondering if my ram is the problem if indeed ram is needed to POST (didn't think it was).

Thanks,

itsbob

- Collapse -
yes, the wrong ps could have killed the mobo
by ramarc Feb 16, 2009 10:10AM PST

i suggest you take it to a shop and let them evaluate it.

- Collapse -
Maybe I see another Problem
by Ol Rod Feb 16, 2009 9:28AM PST

I think I agree with Ramarc, probably some hardware peculiarity. Maybe take motherboard out of case, look for possible short. Maybe try to run it assembled out on the table outside the case? Make sure it is on surface that will not conduct electricity.
SECOND COMMENT: I read your post 3 times, Looks to me that you hope to run the operating system that was in the old Dell. THAT WON'T WORK. Microsoft and Dell fix it so you cannot use that O.S. on another computer. And to them, the different Mobo and CPU makes it a different computer! Sorry to bring that up Sad You can search these forums and find many discussions on moving O.S.

- Collapse -
Using the g31-m7 te with a 300w emachines psu works fine
by carmicd26 Aug 20, 2010 3:59AM PDT

I would start with your mem, and yes mine wont post with bad ram or wrong ram in it either, try crucail.com they got the mem finder ive used and not bad price for 2 gig of ddr2pc5300 for around 43.99 newegg has it for like 42.99 after shipping...

Back to Desktops forum

CNET Forums

Operating Systems
Software
Electronics & Gadgets
Hardware
Tablets & Mobile Devices
General Help
Brand Forums
Roadshow Autos
Off Topic

Other Forums

Forum Info