Need Help for Repair my Ati Hd7950 (FINALLY REPAIRED)

I found Vga HD4850 Pics and in this components, pcb put: CXXX ...

http://www.techpowerup.com/reviews/P.../back_full.jpg

C is for Capacitors.

This components are Capacitors.

Now only need value for this Capacitors.

Vga Car Hd7950 no work in 1155 computers and 775 systems with PciExpress 16x. Black screen.

Only work fine on Msi motherboards at moment. In my Old 775 Msi motherboard and in a friend Dual Xeon 771 Msi Motherboard.

Other computer try init Vga at 16X, then no work, no image.

I update my computer to 1155 system with Core I7 2600, I need repair Vga for use.

Greetings.

Hello Again. Thanks for all responses. At this moment, I am waiting for arrive capacitors for repair my Hd7950.

In Overclockers forum, Member user "Bobnova" said me this response, with value for this Capacitors.

Bobnova Said:

" Those are 0.1µF, 0402 package capacitors. If you replace them, should work fine.
It looks like the pads are still there, so you just need to get some caps and solder them on. The tricky part of course is that they're ****** Any voltage rating over 5v or so is fine.

I'm surprised it works at 8x, as those pairs are for 3x and 4x respectively. ".

I look in google with key " 0.1µF 0402 package capacitors Pci Express " and with " 100NF *(100NF=0.1µF)* 0402 package capacitors Pci Express and found a various links with other people with same problem or similar problem, and the responses and final fixes were obtained with this
0.1µF 0402 package capacitors.

I found too, a April 30 Year 2005 Archive Datasheet Pdf, with Official Technical Data for PciExpress from Philips Semiconductors.

Archive Name is: AN10373_1.pdf

In the archive say this:

"PCI Express requires AC coupling between transmitter and receiver. The AC coupling capacitors for both differential pair signals must be the same value, same package size, and have symmetric placement. If possible, TX traces should route on the top layer.

The capacitor value must be in the range of 75 nF to 200 nF (100 nF is best). The 0402 package size is preferred, and 0603 is acceptable. C-pack is not allowed.

The breakout into and out of capacitors should be symmetrical for both signal lines in a differential pair. The trace separation for routing to pads must be minimized in order to optimize tight coupling between the signal pairs."

The best option is 100Nf and with package 0402... Sure this Hd7950 Card was built with the best components.

I look for this capacitors and on Ebay, usa seller sell me for 9 Euros (with transport cost included), 100 unity of "Murata" 0.1Uf capacitors 0402 10V X7R (45 To 125 temperature support).


When Vga no work with other motherboards, I look for information in google. Possible Dell Block bios, was my first option.

My Card is Dell, but with Amd Reference Original Desing. Then I flashed my Card with Official Bios Update from Amd, (Tahiti Pro Bios June 2012 for update speed clock and memory and Improve Hd7950 performance).

Problem with only work 8x no solved. Is no possible solved, problem is in hardware, without these capacitor,Vga is impossible work in a 16X Slot Pci Express at 16X Speed.

Vga only work in two Msi Mainboards: My Old 775 Msi board and Dual Xeon Quadcore (8 Cores Total) mainboard 5000X Speedster2-A4V from friend.

No work in my Asrock 1155 P67 Extreme 4 B3, no work in my brother Asrock 1155 Z68 Pro 3 Gen 3.

No work In Gigabyte X38 Dq6 (only work for a time in second Pci Express, but in a moment, black screen on windows and no work more in this motherboard and too X48 Dq6 Motherboard).

No work in Asus P5LD2 Se, no work in Asus P5E Deluxe, no work in Dual Opteron mainboard Tyan Tiger K8WE (Friend computers and my all computers).

Without update flash and with update flash to last Amd version official bios, Vga no solved problem with blocked run at only 8X. Repeat, was a hardware problem, without this Pci Express capacitors, Vga is impossible work in 16X.


Thanks to all, for all help. When capacitors arrive me, And I get the card repair, I confirm repair with message in this topic.

Greetings

I now receive message for Hardforum user airthimble with this Pdf,is writed for Pci Express, Pci-Sig:

http://www.pcisig.com/developers/ma...c_id=0a73787e8b6cc2b746ba2c2140a4ed768e93e9df

And say: "

As the next generation of PCI Express is defined, the information throughput will double and yet the symbolrate will only move from 5 GT/s to 8 GT/s. There are some significant changes and challenges:
While 5 GT/s communications used 8b/10b encoding to limit the longest occurrences of consecutive 1’s and 0’s, 8 GT/s will use scrambling.

This has system budget and signal integrity impact on both transmitter and receivers. Baseline wander due to the long runs of consecutive 1’s and 0’swill impact the available eye height.

AC coupling capacitors of 220 nF will be required in order to reduce the baseline wander.

The combination of higher datarate and channel length up to 20”combine to cause Inter Symbol Interference (ISI), in addition tojitter from reference clocks and transmitters. These will limit the eye opening width available".

Thanks and Greetings

Thanks to User Bobnova in overclockers forum.

Thanks to User airthimble in hardforum forum.

Thanks to all users in all forums for responses to my thread message.




VGA HD7950 CARD IS COMPLETE REPAIR. WORK FINE AT 16X AND WORK FINE NOW IN ALL COMPUTERS.

SMD CAPACITORS ARE 220NF 0402 PACKAGE

I BUYED THIS CAPACITORS:

0402 X7R 6.3V

CAPACITOR CERAMIC 0.22UF 6.3V, X7R, 10%, 0402
Capacitance: 0.22µF
Capacitance Tolerance: ± 10%
Dielectric Characteristic: X7R
Voltage Rating: 6.3V
Capacitor Case Style: 0402 ^1005 Metric]
Operating Temperature Range: -55°C to +125°C
Capacitor Terminals: SMD
No. of Pins: 2

NEXT, I carry my card with buyed capacitors to my City local and Spanish Internet Electronic Repair/Sell shop IMPEXTROM. They solded capacitors with high quality machinery. I Have a station solder with pistol gun, but I prefer electronic professional from IMPEXTROM, with better machines, solder this components in delicate pcb Vga.

All ok. Card is complete Tested and working now fine.

Greetings.