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HD 4860: Snapped capacitor, please help.

vorrin

vorrin

vorrin

Associate
Joined
4 Feb 2011
Posts
6
Hello dear people at OverclockersUK.

This is my first post here, first time out of the lurking, for I don't really know where else to turn :).

Some time ago, I bought a radeon hd 4890 at a car-booth sale sort of thing.
It was sold to me as working, and cheap, and I thought to go with the 'I'm feeling lucky' option. Which I wasn't.

When the card is plugged in, and the computer boots, all the fans spin, but there's no video output at all (I am sure my PSU can power an hd 4890, as it did in the past, also, my computer I'm writing you from, and that works too).

After a bit of plugging in and out and scratching my head, I take the card in a bad way, and a capacitor comes off, too (legs still on the PCB, capacitor itself off the legs).

Now, in all my years of hardware messing, I never found capacitors and similar bits to be so frail, so, I am wondering:

1 - whether such capacitor wasn't already damaged to begin with, and could that be the cause for the card not producing any video output.

2 - if so, how/where in the hell could I find another similar capacitor, to solder it back on.

Any reply, especially to question 2, would be really useful, as I haven't got the slightest idea how to find out on my own, I've already tried googling much, but to no avail.

I attach the pictures of the faulty capacitor.

This shows its position on the card:


20110204162856.jpg


And this shows the capacitor itself:

20110204162916.jpg


Thanks in advance!

Vorrin
 
You should be able to buy a replacement capacitor from a NO COMPETITORS! electronics shop, they might even solder it on for you.
 
youl be needing a 270uf Aluminium electrolytic capacitor, id guess 16v but you can put higher on, all it is is the tolerance to voltage so a higher denotion just means it can take more voltage, stick a 20v to be safe.

should run you about £1.50-£2

EDIT, rs are good also checkout Rapid online, used them a few times and found them excellent.
 
Last edited:
Kanifee said:
youl be needing a 270uf Aluminium electrolytic capacitor, id guess 16v but you can put higher on, all it is is the tolerance to voltage so a higher denotion just means it can take more voltage, stick a 20v to be safe.

should run you about £1.50-£2

EDIT, rs are good also checkout Rapid online, used them a few times and found them excellent.
Click to expand...



I think he mean this bit. Easy option is to buy a faulty graphics card off an auction site and use a heat gun to take off and put on the 4890.
 
ah if indeed that bits then im of no help other than retailers lol.

misleading picture was misleading :D
 
Kanifee said:
youl be needing a 270uf Aluminium electrolytic capacitor, id guess 16v but you can put higher on, all it is is the tolerance to voltage so a higher denotion just means it can take more voltage, stick a 20v to be safe.

should run you about £1.50-£2

EDIT, rs are good also checkout Rapid online, used them a few times and found them excellent.
Click to expand...

Yup it's a 16v 270uf capacitor - (made by nichicon from what I can tell - part number PLF1C271MDO1) 58p each from digi-key

LF is the series
270 is the capacitance (270uf)
c is the voltage code (c = 16v)
941 is the lot number (pretty meaningless)
 
Last edited:
 
PhillyDee said:
Thats not a cap pad!

Op: These are a bugger to solder back on. I suggest lead based solder (flows easier) and a flux pen. Tin both the pads on both card and the cap. Apply a lot of flux (no clean flux!) when cool. You can then apply heat via a soldering iron, on both the cap and board, the flux will suck the solder in (use 0.5mm solder for preference) soldering the pads. Repeat for 2nd pad.
The better way is to use a heat gun at 250-275C quickly which should melt the cap to the pad.
Click to expand...

Caps are probably the easiest thing to solder as long as you clean the solder pads first using wick or a sucker. You just poke the pins through the hole (checking the orientation first), add a little solder and clip off the remainder of the pins. What exactly makes that a bugger? They are through hole not even surface mount!
 
^Andy^ said:
Caps are probably the easiest thing to solder as long as you clean the solder pads first using wick or a sucker. You just poke the pins through the hole (checking the orientation first), add a little solder and clip off the remainder of the pins. What exactly makes that a bugger? They are through hole not even surface mount!
Click to expand...

Heh, thought they were surface mount ones! Hence the 'pads' :p
 
Thanks a bunch everybody!

Phatzy: I did mean the cap with 'LF 270 C 941' on it, the one you can see in the pic, the capacitor came completely off of its two metal legs, so it's just plugged there, sitting in its normal position, but I reckon it might well not be working.

Kanifee, ^Andy^: thanks for the explanation, I was really wondering what those numbers meant.

So I will get one capacitor as described, and solder it on, in the hope that was initially the only problem with the card. I'll let you know how that went :)


Cheers!
 
vorrin said:
Thanks a bunch everybody!

Phatzy: I did mean the cap with 'LF 270 C 941' on it, the one you can see in the pic, the capacitor came completely off of its two metal legs, so it's just plugged there, sitting in its normal position, but I reckon it might well not be working.

Kanifee, ^Andy^: thanks for the explanation, I was really wondering what those numbers meant.

So I will get one capacitor as described, and solder it on, in the hope that was initially the only problem with the card. I'll let you know how that went :)


Cheers!
Click to expand...

Good luck - as long as you carefully desolder the broken off pins and clean up the holes you should be fine - you may need some desolder braid to help you with that to minimise the risk of lifting the traces off of the pcb.
 
well then, it looks to me that that from that picture there is also some SMC missing (blown off) on NF1200, poss diode or resistor.

Unless the picture is not of your card?
 
Its_Me said:
well then, it looks to me that that from that picture there is also some SMC missing (blown off) on NF1200, poss diode or resistor.

Unless the picture is not of your card?
Click to expand...


Doesn't look like anything was ever soldered in that location to me. It's pretty common for the pcb to have solder points for components that are not installed (the same pcb's are usually used for multiple different models of card).
 
Looks to be the remains of something attacked to the pads, usually they would be flat and silver in colour.
ofc it could be a trick of the picture, but it looks the wrong colour and has some SMC remains.
 
Its Me: I see your point, and thanks for the suggestion, as I don't know what the fault was to begin with, with this card, anything helps :)

Giving a good look on the card itself, though, it doesn't really seem there's anything wrong with that bit, definitely looks like it came out of the factory so, there's no sign of anything being snapped off, or torn away or so, neither on top, nor on the bottom of the card, so I think that is probably supposed to look that way...


Anyway, I've ordered the capacitors from RS, they shall have them tomorrow :)

In the meantime, I've done some minimal toying with soldering, but mostly when I was quite small, so I don't really understand some of the advice I got about that (ie. dunno what a desolder braid is) , if anyone would have a fairly simple and good tutorial on something like what I'll need to do at hand, that'd be nice.

Else I reckon I shall find something on google about it without sweating too much.

So, will let you know soon, my main fear by now is that the capacitor had nothing to do with it in the first place, in which case, after that I'll be lost as to 'how do I fix it' -_-
 
vorrin said:
Its Me: I see your point, and thanks for the suggestion, as I don't know what the fault was to begin with, with this card, anything helps :)

Giving a good look on the card itself, though, it doesn't really seem there's anything wrong with that bit, definitely looks like it came out of the factory so, there's no sign of anything being snapped off, or torn away or so, neither on top, nor on the bottom of the card, so I think that is probably supposed to look that way...


Anyway, I've ordered the capacitors from RS, they shall have them tomorrow :)

In the meantime, I've done some minimal toying with soldering, but mostly when I was quite small, so I don't really understand some of the advice I got about that (ie. dunno what a desolder braid is) , if anyone would have a fairly simple and good tutorial on something like what I'll need to do at hand, that'd be nice.

Else I reckon I shall find something on google about it without sweating too much.

So, will let you know soon, my main fear by now is that the capacitor had nothing to do with it in the first place, in which case, after that I'll be lost as to 'how do I fix it' -_-
Click to expand...

Google is my advice but you need to try and clear all of the solder from the original solder points leaving the 2 holes clean for you to pass the legs of the new cap through and solder into place. Solder braid helps by soaking up the existing solder and making it easier to remove. There are plenty of good tips on soldering and desoldering to be found on the net.

You will definitely make the job much easier for yourself if you can cleanly desolder the remains of the busted cap and clean up the 2 holes though - just be careful not to overcook it or force it at all as that could damage the trace on the pcb leaving you nothing left to solder to!

Do you have any scrap electronics to practice on?
 
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