Need help for repair my Ati Hd7950

[Filrond]

(FINALLY NOW IN APRIL 28 2013, VGA HD7950 IS COMPLETE REPAIRED)

I buyed months ago, a HD7950 Card with 3GB in local Shop.

I used this card in Old computer 775 with Msi motherboard, and Vga work fine.

I Update this computer to 1155 system with Core I7 2600 and Asrock Extreme 4 P67 B3 motherboard.

Ati Hd7950 no work with this system. I tested it in other 1155 system with Pci 3 Gen and no work.

Finally I send message for help to Amd. Finally a lot of send messages replies to Amd.

I discovery, I was a great swindled. My local shop sold my a Dell Vga Hd7950 Card...... This card is no for sell in local shop, is card for sell with Dell Computers.

My card only work in Pci Express 16x working at 8X. No work in motherboards with Pci Express 16x at 16x .

Then I decide check my Vga Hd7950, and then I found problem...

Two smd components (Resistor or Capacimeter), missing in Card.

This Two smd components, are in the area of PCI Express Vga connector with the motherboard (where the pins). This missing Smd no appears broken, this missing Smd appears removed by Dell for use Vga at 8X in Computer Dell.

I look in google, other users problems with Vga Card only work at 8x Pci Express 16x, finally found exact problem with missing Smd components in the same zone Vga.

I have a Electronic Solder Skills. I have a Station solder and large experience with repair electronic components. Is easy for me resolder this two smd components.

But, I have a problem. I do not know who exactly are these Two SMDs.

1)Are resistor or capacimeter?.
2)And what is electronic value for this Resistor or Capacimeter?.

I have looked, this smd appears are standart in all Pci Express Vga Cards... but not sure.

I have a Dead Hd4890, and I can remove this two Smd from this Broken Hd4890 and later solder in my Hd7950..

But I prefer to be sure, these components are the same and have the same value.

Do any of you, known to be and what value do they have?.

I added Pics for my Vga Card and for Zone hardware problem and missing Two Smd.

My Card:





Two Smd Zone missing/Damage Pic from my Vga Card:





Other Pic from Google with Reference Card Hd7950. (All Smd in Zone)





Other Pic from Google with Hd7950 Twin Frozer (All Smd in Zone)





Thanks for help

[STEvil]

Look at your 4890, if the component is in a nearly identical location with the underlying traces connected to the pci-e slot like the 7950 and appears to be the same color you should be able to swap it from the 4890 to the 7950 without worry. The part appears to be a capacitor.

[chispy]

Let me see if I can be of some help , I took my HD7970 and measured the ohms to ground from those capacitors , all of them have the same value in my card wich is an MSI lightning HD7970 , im almost sure if you measure the one next to the missing one it will be the same value most likely , on mine it shows 561 ohms to ground from all those capacitors using my Digital MM . I checked for you number 5 and number 7 the ones that are missing on your card , they are capacitors of 561 ohms. Please measure one with a Digital MM and check your old HD4890 to see if is using the same value in ohms ,if it does just re-solder two of them back from your old HD4890.

Excuse my Spanish for a second guys I think he speaks and understands better in Spanish ( Si hablas espa?ol y no entiendes en ingles dejamelo saber yo hablo espa?ol as te puedo ayudar mejor )


Capasitor numero 5 en my tarjeta grafica :




Capasitor numero 7 en mi tarjeta grafica :

[CrazyNutz]

They are not resistors. They are capacitors.

I don't know the values, however you should be able to remove these from any cheap pcie card and put them on your 7950.

If you found the PCIe electrical spec. doc it would probably recommend a value for these capacitors.

[STEvil]

I was helping a friend move today and checked some cards in his stockpile of parts and most of them seem to have identical parts in that location regardless of being nVidia or ATi/AMD.. so you're safe to use them from what I can tell.

[Filrond]

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 0.1?F, 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 " 0.1?F 0402 package capacitors Pci Express " and with " 100NF *(100NF=0.1?F)* 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
0.1?F 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

[Filrond]

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

http://www.pcisig.com/developers/mai...a4ed768e93e9df

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

[Filrond]

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.



UPDATE:

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: 0.22?F
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.

[PaganII]

Good Work! Congratulations!

[Ket]

I love happy endings ^_^