# Need help finding the values of missing capacitors

#### desecravity

Joined Jul 23, 2013
3
Hi to all from All About Circuits,

Firstly, I am new here, and I apologies if this thread is not in the right section. Now to business.

I have recently come across the opportunity to purchase a brand new EVGA GTX 690 graphics card at a great price. The catch is, the card is faulty, and the seller (an online electronics 're-seller') does not know much about graphics cards, and has not tested the product to see if it works or not. The card has never been used, and was obtained from Best Buy by the seller with the message 'Missing two resistors' on the packaging. The seller does not know any more about the card, and is selling it as is. Pictures below.

I have limited knowledge when it comes to electronics, but from what I can see in the picture, the two missing parts are in fact capacitors, and not resistors. And.... here is my dilemma, without the circuit diagram of the the cards PCB, I cannot find the value of these missing capacitors, and as such, I have no idea if this card is repairable or not. I have searched online for this information, but to no avail.

I am here on All About Circuits with the hopes that any of the members here can tell me if this information is available to the public and where I could find it (circuit diagram of the GTX 690), or even better, if someone with a 690 has dealt with a similar problem and knows the values already (one can only hope, right?).

Lastly, I am well aware that this is a risky purchase, but given the above information would you think this purchase worth while (i.e capacitors can be replaced), hell there might even be something else wrong. Or would you consider this a complete waste of money? Keep in mind the card is going for about 25% of the price of retail.

PS; Soldering, and any other electronic work is not a problem, and should be left out of the equation.

Gus.

#### sheldons

Joined Oct 26, 2011
613
waste of money-you will be very lucky to find any info on this pcb,plus they are surface mount components.....if they are decoupling caps then any value from 0.1uF upwards should be ok

#### MrChips

Joined Oct 2, 2009
23,528

#### wayneh

Joined Sep 9, 2010
17,152
It's hard to tell from the photo - were there capacitors there once in place that got physically knocked off? It's quite common for a PCB to appear to have missing components, due to redesign I suppose. The note regarding missing components was probably pure speculation by someone that knew nothing.

Plug and chug - testing - may be your only approach. Just keep trying caps until you give up. Have you tried the card as-is?

No offense, but spending $250 for a non-working video card is pretty nuts, IMHO. #### Dr.killjoy Joined Apr 28, 2013 1,196 It's hard to tell from the photo - were there capacitors there once in place that got physically knocked off? It's quite common for a PCB to appear to have missing components, due to redesign I suppose. The note regarding missing components was probably pure speculation by someone that knew nothing. Plug and chug - testing - may be your only approach. Just keep trying caps until you give up. Have you tried the card as-is? No offense, but spending$250 for a non-working video card is pretty nuts, IMHO.
+1
I fully agree with you..
Nut in reality you are posting on the wrong forum for what you trying to do .... Check out Overclockers.com and see if those guys can help because those guys mods card all the time to get max performance ..

Here is my rig so far but way over due for a upgrade
MB~GIGABYTE GA-880GM-UD2H AM3 AMD 880G CPU~AMD Phenom II X2 555 BE
MEM~CORSAIR XMS3 4GB
GPU~ Sapphire ATI HD 4870
HS~Spire TherMax Eclipse II Five D.T. Heatpipe
TC-Tuniq TX-4 Extreme Performance
PS~Corsair VX550W
HD~SAMSUNG Spinpoint F3 HD103SJ 1TB 7200 RPM
CASE~Rosewill CHALLENGER

Joined Feb 27, 2010
249
its the same with a lot of tv boards and other electronics. even if you get the service manual, you will be lucky to find a detailed schematic and parts list in there for the board you need to troubleshoot. companies dont typically share that sort of information.

thats why the only real way to troubleshoot something like that is to have an identical video card thats working. must be exactly the same make, model, and revision though.

#### THE_RB

Joined Feb 11, 2008
5,438
I'll go a bit "Sherlock" and deduce that the two caps knocked off the PCB were caps with significant height, like C388 etc.

In that case they were almost certainly larger value caps, for non-value-critical PSU decoupling or filter cap use.

C791 is very likely the same size and value as the 3 caps next to it, in a row.

I would solder in a couple of high value 0805 ceramics (3.3uF? 6.8uF? 10uF?) whatever you can fit in there. That should get it up and running fine, assuming those 2 missing caps were the only problem.

It's worth checking the whole PCB carefully for any other physical damage.