[Problem] A resistor on a 3850 256MB!

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os008

n00b
Joined
Nov 21, 2007
Messages
20
Hi everyone,
My hands for 'some' reason jerked while i was soldering the wire next to that resistor, so i chipped it off, i then removed all the soldering i made, started up the computer, but the card didn't display any picture on the screen, however, it booted into windows, cause i could hear the harddisk working, then the loggin windows sound.

I then got a replacement resistor (based on an advice from a friend), and it worked again no problem.

Then, i was measuring the voltage of the core to make sure everything is ok, it measured 1.2v, i increased it a bit by bit to get the max for my cooling, i reached 1.53v, got 930 on the core, stable and everything again was excellent and fine.

Decided to wrap it up, and close the case, but decided to measure the voltage one last time just to be sure, worst mistake of my life ... shorted the +ve and -ve lead from the PCI-e plug to card by accident (out of excitement, or maybe i have some nerves problem :rolleyes::eek::(), it made a spark, then no picture, just like before.

It could boot into windows still, same previous problem, so i simply tried increasing of decreasing the resistance (from its default of 1.2v, i returned everything to default just in case), not budging, boots into windows but no picture from the computer startup.

Oh, one more thing to note, before i fixed the first problem, and also during this last problem, in both cases the voltage reading of the core was zero.

I know i screwed up BAD, because i'm careless when i get excited :rolleyes:, and i know i burnt something, so, my question is ... can this be fixed, or is this the 'real' end of it.

I'm going to get a 8800GT next week anyway, but would like to get this card working still, it would be a waste not to :(, especially that i learnt a LOT of lessons in modding, and in electronics from tampering with it, and above all, in carefullness :p.

I would really appreciate any help, thanks a lot guys :).
 
I wish i could see the damage, at least i would have known by now what has happened, but the card doesn't have even a darker area, or a smell of smoke, nothing :(.
 
you are going to need to test every resistor, there is a chance you have just blown the one you fixed.
 
I measured a nearly EVERY resistor near the power regulation area, 50% of them have zero ohm resistance, is that normal :eek:, i mean, i measured like 30 of them or something, and a lot of them measure 'zero' ohm, shorted.

Could the mistake i made above cause all those to short out like that? OR, did you mean by testing them ... to check if one or more has max resistance (testing it but no reading on the DMM)?
 
Have they got any bands on them?

They could just be bridges.
 
Some have '000' on them, and some are a bit small to have that number marked!

But, what do you think i burned by that short, could it be the main voltage regulator chip on the back of the card?


EDIT: sometime when i measure a resistance, it starts at say 3 Ohm, then goes up gradually to 10, and keeps on going, i just stop measuring lest it burst or something :D, is that a Capacitor charging? i mean, near that resistor, cause i'm sure it was a resistor (black), while capacitors are yellow, right?
 
Hmmmm, Robo, are you sure man? cause the 'thing' i chipped off was black, i got another one as a resistor and it worked.

Or another way to put it ... what are the yellow ones?
 
Finding out what happened would be a bit difficult to do. I'd start by looking and testing for resistances around the area that you shorted. It is very likely that you broke a component (you can't always tell by just looking), and that part or several parts need to be replaced.

I don't think this has anything to do with the resistor you added/replaced, as this is a totally different event, unless you shorted at that resistor.

Either way, I'd say you've got a lot of work ahead of you to try and find out why this card isn't working. I'd wait for that 8800GT unless you've got a lot of time, a multimeter, and some electric circuit experience (or the will to learn ;)).
 
Thanks for your reply, indeed i felt it would take a lot of time, so i'm waiting on the 8800GT now, in a sense, it's an upgrade, so not all a loss, lol.

I tried testing the components around the PCI-e plug, it's a bit hard without experience on what reading to expect, nearly all the components give me a reading, non are broken in the sense of giving no reading, so i guess i have to give it to someone who knows in those stuff to test it out for me and try to repair it.

Thanks.
 
os008 said:
Hmmmm, Robo, are you sure man? cause the 'thing' i chipped off was black, i got another one as a resistor and it worked.

Or another way to put it ... what are the yellow ones?
Click to expand...

The yellow ones, IMO, are generally caps...
 
Yellow ones with a marking on one end are usually tantalum capacitors, polarized. Electrolytics ones are fairly obvious ("can" caps), and the other SMD varietes are usually brownish in color (they will probably be labeled Cxx with a number). Don't know where the mention of caps being black came from...some electrolytics are black, but its completely obvious they are caps.

Black SMD parts in the 1206/0805/0503 sizes are almost always resistors/bridges or similar, though jumpers are usually black or green with '000' screened on their top.
 
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