Another oops to amuse you.....

[Lieutenant Scott]

I don't know if I told you but I have a graphics card that's out of warranty and stopped working. Well I checked for swollen or burst capacitors, there weren't any. So as a last resort I tried the bake in the oven method to reflow the solder.

9 minutes at 196C as advised. The solder didn't appear to have melted, and the card remained inoperative. Perhaps my oven thermostat is inaccurate? Try hotter! Max - 240C. BANG! Now I've got burst capacitors. All over the oven. I shall refrain from reinserting it into the computer.

[Brian Gaff]

I'd have thought this outcome was pretty obvious. think about the soldering. When its done its fast and localised to the parts needed to be soldered. One cannot heat the whole card up and expect it to survive.

Brian

[Moonraker]

I'm sure the Lt. realises that now, but there we all have 20/20 hind sight.

[Pete Shew]

I fixed a terminal laptop with 8 minutes at 180 (just the motherboard). Googling showed that a common fault was overheating GPU causing solder coming unstuck. Early attempts with a blowlamp didn't work, but the oven cured it.

Reassembled with a bit more pressure on the heatsink :-)

[eastender]

Talking of kitchen appliances, I tried cleaning a keyboard that had not-working keys by giving it a good going over in the dishwasher. I got a spakling clean keyboard but it still didn't work.

E.

[Man at B&Q]

nty and stopped working.

Advised by who, FFS?

Reflow needs a short preheat, and an even shorter pulse of maximum temp, othrewise you will just destroy the components.

MBQ

[Dave Plowman (News)]

So isn't really possible at home? Or could it be done with two ovens? And at what temps? I have a decent probe so could set them quite accurately.

I've got a graphics card which is also intermittent, so wouldn't mind having a try.

[Mr Pounder]

Mr Hucker knows everything.

[Jules Richardson]

Usually[1] down to impurities/residue in the water/cleaning solution. Splitting things down into component parts, cleaning, then rinsing with distilled water and drying immediately helps a lot.

Beware of liquid getting trapped under ICs, too. Blowing accumulated moisture from PCBs with compressed air or bunging in the airing cupboard for a few days is usually a good plan.

[1] although modern keyboards usually use a flexible plastic membrane for the key switch matrix; it's not impossible for one of the tracks on the membrane to break (people who owned Sinclair Spectrums back in the day may remember that fault, too!), which will also yield various (and perhaps bizarre) combinations of non-working keys.

cheers

Jules

[Andy Dingley]

Mate of mine tried that and got a sparkling clean keyboard that worked perfectly.

Bit hard to type on all those unlabelled keys, mind.

[Andy Dingley]

eBay, China, buy yourself a surface mount workstation. Surprisingly cheap these days.

[John Rumm]

The "proper" fix is to reball the GPU, but that requires a bit more equipment. The simpler (but less good) fix is to just reflow it.

can get proper SMD IR stations from ebay for about £160. That includes a tempering platform to pre-heat the board, and then a IR lamp that you can position and focus on the device in question (foil tape / baking foil can be used to screen adjacent parts.

The cruder solution it to reflow with hot air - either a proper SMD rework air system (CPC £70), or even just a paint stripper gun can be used. These methods are less precise, and more likely to stress the board. However with care you can pre-heat the board a bit by using more distance and playing the air stream over the board (or just a few mins in a 100 degree oven), then moving in for the reheat on the device.

I have successfully reflowed an HP laptop with nVidea GPU problem using nothing more than a paint stripper and a few layers of tin foil.

[Dave Plowman (News)]

I've already got one. But that doesn't preheat the board and re-flow everything in one go.

[John Rumm]

You generally don't want to reflow everything in one go other than during initial assembly (where the toaster over techniques work well since you can do that before fitting anything temperature sensitive to the board). So general tempering and then targeted IR or hot air is what usually works.

[Lieutenant Scott]

It is stated on the internet that several people managed it. However the original fault of mine was unknown.

I thought professionally it was still with the whole thing in an oven, perhaps faster though.

[Lieutenant Scott]

A drunk apparently once fixed a motherboard they'd spilt beer on by washing it in the bath. The board functioned fine.

I spilt water on mine once (leaky watercooler). I simply dried it out and it still worked.

[Lieutenant Scott]

and stopped working.

[dennis]

Its relatively easy if you have access to a vapour phase soldering bath. They don't take anywhere near 9 minutes and you don't fit your through hole din edge connectors, etc. first as they tend to melt. They are usually flow soldered afterwards.

I have a broken Nvidia GPU on a Samsung laptop to fix so I may get the daughters hot air craft gun on it.

[Dave Plowman (News)]

Standard practice. Just rinse well and dry gently before applying power. A couple of days in the airing cupboard is best.

[Lieutenant Scott]

This was a Nvidia aswell. It broke when it reached the low 90s C when in use (poor cooling design by Inno3D). Radeons don't break like that. They run at

100C for hours without breaking, they just start making graphical errors. Why can't they make them with a thermal throttle like the Intel processors?