How to determine or troubleshoot to find out which component is bad

[xboxhaxorz]

I have a broken video card that does not show any picture nor is it detected in windows when used as a secondary card. I was wondering how i might go about determining which smd components are bad so that i may replace them. There was a piece that was physically damaged so i obviously new it was bad and replaced it. But if they physically look fine, how can i tell which component is bad? I have checked and verified the IC chip to be fine.

Performed a reflow on it 3 times with no condition change. Was going to go for a reball of the IC but after using it in another slot and windows not detecting i knew that would not help and something else was the problem.

 

[mdanh2002]

Buy a new one. They are relatively cheap these days, and the efforts and time spent on troubleshooting may not be worth it. Not to mention that a repaired card will never be as reliable as a new one and can fail at any time, risking further damage to the motherboard. A few years ago I fried my motherboard when trying to get Windows to detect an old Sound Blaster 16 ISA card.

 

[xboxhaxorz]

gotcha
i wanted to do it for my own personal knowledge and skill since i am evolving my repair skills. but did not think about damaging the mobo, that alone is not worth it at all. thanks totally forgot about that

for my own personal knowledge, which is the best way or is there none to go about figuring out which component is bad?

 

[mdanh2002]

I think without specialized equipment and the full circuit schematics of the card (which the manufacturer seldom makes public), you can only identify loose connection and visually damaged components such as burned ICs or bulge capacitors. I know how to visually identify bulge through-hole capacitor (they are easy to spot). These are much more common on old ISA sound/modem/network card and seldom found on a PCI or AGP video cards, which use mostly SMD components. I think faulty SMD capacitor can only be tested using an ESR meter - but again they are too small, how to probe? And even if you could identify the faulty components, it's difficult to replace - these types of cards are not made to be repairable. When it fails, send for RMA if warranty is still valid, otherwise throw away.

 

[xboxhaxorz]

Thanks that makes a lot of sense. Will keep in mind.

 

[HiTech]

What amazes me are the very thin foil traces and feedthrough connections on PC cards. They can be a sensitive failure point that's extremely difficult to troubleshoot, thereby making it far easier and less stressful to simply replace with a new board. I'm amazed how those tiny traces manage to not break from flexing, let alone the multi-pin sockets soldered to them and the torque applied when affixing a connector to it.

 

[MakII]

If you have a huntron you can use it to look for shorts and check your diodes and caps. also use a multimeter to check resistors for the correct tolerances and continuity check all traces.

 

[mdanh2002]

I think resistor values cannot be measured precisely if they are still connected in circuit. At least one leg has to be removed from the circuit, which is troublesome on through-hole components and impossible on SMD components. The best you can do is checking for continuity.

 

[gary350]

I use to repair circuit boards back in the day when they could actually be repaired. Now days circuit boards are a throw away item. You can't read the part number on many of those surface mount components so there is now way to look it up without a part number. Lets suppose you managed to find a bad surface mount part then you have to order one and you have to pay postage to get it. So you got maybe $1 at the most in the part and maybe $6 to $10 in postage. Back when I was repairing circuit boards I ordered parts in lot quantities of 250 or more. After repairing the same stuff over and over it doesn't take long you know whats wrong without testing it so you just change out some parts then see if if works.

Buy a new video card.