I just purchased an Diamond HD 3870 512 MB card to replace my crossfired X1950 pro cards. I uninstalled the catalyst drivers and shut down the machine. I removed the old video cards, and installed the new card in the master PCI slot. Problem is, when I boot up the machine with the new card, the monitor does not get a signal. I am using a Viewsonic VG2030wm monitor, with DVI. I've tried both DVI ports on the card, and even tried switching the new card from the master PCI Express slot, to the Slave slot, with no luck. I have double checked that the card is properly seated, and that the 6 pin power cable is plugged in. I also checked to make sure that the master slot was working, by putting one X1950 Pro card back in. I am going to try driver cleaner, but I don't think this is the issue. I know that the new HD 3870 card is getting power and that the fan is running, but am baffled as to why it doesn't send a signal over the DVI to the monitor. Any input would be appreciated.

Try putting your old card in and updating the motherboard BIOS to the newest version.

^-- I'd probably do this first as well..but..

The only thing I can think of cause this happened to me, (But I don't think it's your problem, since you said you put your old card back in to make sure it was working.) check your PCI-E slot on your motherboard to make sure it's not cracked or broke. (When I installed my massively heavy X1950 XTX I wasn't careful enough and the PCI-E slot got bent..hah yea..) Other than that... it might just be a defective/bad card. What motherboard are you currently using?

The PCI Express slot is in good shape. I'm using an MSI K9A Platinum motherboard, with bios version 1.7. The latest bios verison is 1.8, but according to msi, it is to improve compatibility with sempron processors. I will give it a try though.

I recently replaced my Diamond X1950XTX with the Diamond HD 3870 card and had a conflict with the HDMI sound device and my on-board sound. I know yours is a different issue, but I did have a heck of a time removing the old ATI drivers. I would uninstall the old drivers, boot into SAFE MODE and use Driver Cleaner to clear the old ATI drivers out. I might try disabling and re-enabling the video in your BIOS set-up. Another thought, is there a Device Driver for that second card that you may need to remove or disable. This stuff can be a pain

I have that mobo tiz great i only have 1.4 drivers on it and both my 3870's ran fine. I would norm guess PSU however you had X1950's in CF so that definately isn't the problem. Sounds like it may be a duff card as i didn't have to change any settings in the bios to get my pair to work.

Hello again,
Good news, after many hours of trouble shooting, I have the HD 3870 working. At least in windows. Games work great. The only issue that still remains, is that when I boot the computer, I can no longer see the boot information. This also means that I can't see the BIOS to make any changes, which is annoying. I may hold onto one of my old cards for a bit longer to get a new BIOS update. Anyone know of a free cd burning software, which will create a boot cd? I can't use nero's try and buy because it says that the license is expired. Thanks for the input.

Not to sound stupid, but have you tried accessing your bios at boot by pressing F1 or F8 or F11? Or even F5, dont know which one your board/bios requires.

Yes

My situation is identical to your's. My card appears to be working and I've tried everything to assure I'm doing things right but I'm still not getting a signal to my LCD or even my brother's CRT monitor. The only thing I could think preventing me from getting my 3870 to work is that I have a 650i chipset on my mobo (but I don't think that should even prevent me fom using ATI). My power should be good (I have 500watts) and this is the second card I've tried (already exchanged another one for having the same issue).

My question is, what troubleshooting did you do to get things up and running? I'm feeling distraught and wonder if I should go get my money back from Fry's and order a 8800gt from newegg, or to just get money back and sit with my 7950gt for a while longer.

Oh yeah, I have a Visiontek 3870, but I doubt that makes too much of a difference.

I just wanted to leave an update to my issue. I was able to run live bios and update my bios to v. 1.8. There has been no change in the problem that I've been having. My computer will still boot, but my LCD will show a message, no digital signal, and I can't see any of the POST. I will however get a digital signal to my LCD after windows loads.
This is still unacceptable, because, I can't see my BIOS to make a change if needed with the HD 3870 card. I've tried numerous times to get live chat support from Diamond, but I don't get any response. I've also tried to sign up for support, but their site simply gives me an error message and that required fields are not filled out, in spite of the fact that I've double checked that the fields are filled out. I've sent an e-mail to Diamond's customer service, with no response. I finally tried one more live chat, but after waiting for a number of minutes with no response, I typed a message to them that I can't recommend their product to anyone. I simply contacted Fry's and they allowed an RMA no questions asked.

Trouble shooting wise, I was never able to get the HD 3870 card operating properly. Even after uninstalling catalyst to get rid of the HD 3870, I lost the signal to the monitor once the driver's were removed. I decided to just install my old video cards and live with them for the time being.

Yeah, I had my tech-savy friend come over today and after an hour of messing with it he told me I should've stuck with nvidia (he's somewhat of a fanboy) but I've more or less decided to just get my money back and wait for later to get a new card.

Similar issue here with a diamond HD3850 I just got last night. PC boots all fans, HD's and lights(corsair memory with the lights on them flash normal) I just get no video signal. Tried another 3850 in the same PC and I get a signal. Only difference is my original ones are sapphire 3850's. I guess diamonds are junkola crapola. Sending back as a DOA to newegg.

One thing I will try later on today is ATI Tools 0.27 beta 4 to adjust my 3870 fan speed since the card just randomly crashes my system. I am suspecting the fan does not increase in speed as the workload increases.