GPU caps solder doesn't melt for nothing. Even with the soldering set to 500c - Page 1
Forum section: electronics / beginners

author: snowzord
author_rank: Contributor
timestamp: December 22, 2016, 05:46:14 pm
content: Hi! First topic here, i hope i can get some helpFirst of all, i know that there is a topic similar to this one but i already tried all the options there and no positive results so i'm trying my luck on a new topic.So, basicly, i am a owner of a 7870 for almost 2 years. Till one year ago it worked fine but one day it started showing artifacts on Windows and on BIOS. After taking it apart and inspecting it i saw a bad capacitator but my "stupid-side" turned on and i decided to put the whole card in the oven for the "famous" oven reflow method. oh gosh, i was so dumb back then.After several minutes in the oven, all the eletrolytic caps started to pop it looked like a firework show inside my oven. I quickly stopped the oven, opened it and let the card cool down. From that day that i haven't even once inserted the card back on my PC. Some months later (ebay shipping times and so) i got all the caps that i needed to change the bad ones. Picked up a 15€ soldering iron from local eletronics shop, saw some tutorials on youtube and was hoped to fix my card, but no, the solder around the caps legs wouldnt melt for nothing. So after this i opened a topic on a portuguese (i live in Portugal) eletronics forum and they said to me to buy a soldering gun because it was more powerful. Bought one and tried once again to melt the solder around the caps legs but nope, once again the solder wouldn't melt.Went to back to the shop and bought a solder sucker, desoldering wire and water based flux. Tried all of those 3 and no sucess too. Tried lead-free and leaded solder and no results too.Since i had a long-term wish of getting into reballing and reflow's and knowing that i would need a rework station I waited till i got it (some days ago) to try again. And once again, the solder would not met, even with the soldering set to 500c (max). Tried both solder again (lead-free and leaded) and it seems that solder "slides" around the legs of the caps and it doesnt joins the existing solder on the cap leg. Already tried too to apply heat on the caps legs with the hot air gun in the rework station (heat set at 150c) and then use the soldering iron to desolder it and no sucess, once again.Feeling kinda desesperated to confess :|I hope i can get some help,Greetings snowie.

author: joseph nicholas
author_rank: Frequent Contributor
timestamp: December 22, 2016, 06:56:28 pm
content: Compter video cards have multi-layers, in order to get the cap out you will need a 100 watt + soldering iron to heat all those layer up to melt the solder. I tried this one my motherboard and was able to do it with a 60 watt iron but it was a struggle and I don't think I can get the new ones in without more horse power. Hope this helps.

author: SVFeingold
author_rank: Frequent Contributor
timestamp: December 22, 2016, 09:11:49 pm
content: As joseph said, some or all of those caps are most certainly soldered to large ground/power planes and will be a bear to remove. I had a hard enough time removing a micro USB connecter with my 80W Weller station and that was in a phone motherboard. A GPU will have way more mass. I'd say you need to pre-heat the board and get a proper iron. My process in these situations is preheat -> apply flux -> clean tip and add a bit of solder -> keep iron on joint for a few seconds after it appears to melt -> solder sucker. If they're SMD components then wick, but I'd probably break out the hot air for that since you need both solder pads to be liquid. It's a pain but doable. Use the biggest tip you can find. I wouldn't feel comfortable keeping the iron on the joint for more than 5-10s, else you could risk damaging the pad. The old components you don't care about in this case.And don't set it to 500C, that is waaaay too high. And it's counter-productive - at those temperatures a cheap iron tip will oxidize in no time and cut your heat transfer down by at least an order of magnitude. No bueno. You need more power, not higher temperature.Since it looks like you're interested in getting serious about electronics hobbying/rework in the future, you might want to invest in a decent solder station.

author: Jeroen3
author_rank: Super Contributor
timestamp: December 22, 2016, 09:21:51 pm
content: You will need a pre-heater. Multilayer planes are a challenge.

author: wraper
author_rank: Unknown
timestamp: December 22, 2016, 09:28:54 pm
content: Quote from: snowzord on December 22, 2016, 05:46:14 pmAnother one wanting to get on that myth and scam bandwagon.You need a soldering iron with a large enough chisel tip, preferably wide enough to cover both leads of the cap simultaneously. Also tip must be properly tinned. If you got some nickel plated crap of the tip which cannot be tinned, it will be completely useless. Small conical tips will be useless too, even if of good quality. And better preheat the board. Use leaded solder. For desoldering you could also use Wood's metal (70oC melting point) or something similar. Remains must be removed after that, as otherwise it will impact reliability of the solder joint.

author: snowzord
author_rank: Contributor
timestamp: December 22, 2016, 10:42:52 pm
content: Quote from: SVFeingold on December 22, 2016, 09:11:49 pmQuote from: Jeroen3 on December 22, 2016, 09:21:51 pmQuote from: SVFeingold on December 22, 2016, 09:11:49 pmQuote from: joseph nicholas on December 22, 2016, 06:56:28 pmhi guys!huge thanks for all the feedback!one detail that i forgot to mention, the rework station i got: Baku 702B. It looked pretty decent to me, even a user here on eevblog said it was pretty good for it's price point.Luckily i have a pre-heater on it's way to my home so that may do the trick!btw, @wraper can you please explain what you mean with: "Another one wanting to get on that myth and scam bandwagon." I tried to understand but you know, my english is far from perfect in terms of understandingthanks once again

author: wraper
author_rank: Unknown
timestamp: December 22, 2016, 11:40:10 pm
content: Quote from: snowzord on December 22, 2016, 10:42:52 pmSo I'll post this video again.

author: senso
author_rank: Frequent Contributor
timestamp: December 23, 2016, 02:50:06 am
content: BUT ITS NOT A REFLOW..Its a busted eletro cap.And as I have already said in another forum, its almost impossible to do that at home without decent tools/spending much more than the card is worth..Those caps wont prevent the card from booting and displaying an image, if it does not, its dead.And if you are "desperate" you can pull the old caps and have the leads of them exposed and then just solder your new cap leads to the old cap leads and its done, the extra 5mm of lead will not impact the capacitor job where it is.

author: lordvader88
author_rank: Frequent Contributor
timestamp: December 25, 2016, 04:00:04 am
content: Quote from: senso on December 23, 2016, 02:50:06 amthats what I just thought, if the pads are fine, but the smd part is busted, just try soldering anything at all in parallel over itworth a try

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: December 25, 2016, 09:23:11 am
content: You can try to use this low melting solder pastehttp://www.ebay.com/itm/100g-Solder-Paste-Lead-free-Low-Temperature-SMT-Melt-Melting-Point-138-C-SD-528T-/321990643524?hash=item4af8234f44:g:tKQAAOSwvUlWqG6vPut some on the leads. Then use your soldering iron. It will melt and it seems that it will also lower gradually the melting temp of the existing solder. Very efficient.

author: tatus1969
author_rank: Super Contributor
timestamp: December 25, 2016, 10:12:18 am
content: Quote from: Jeroen3 on December 22, 2016, 09:21:51 pm+1. you can use your oven to preheat the entire board to 120°c, then be quick and you should be able to remove the caps. use a short thick tip, and your iron should be temp controlled. use leaded solder.

author: TheAmmoniacal
author_rank: Unknown
timestamp: December 25, 2016, 10:14:48 am
content: And melt a good-sized blob of solder onto your iron, for making good thermal contact with the joint.

author: snowzord
author_rank: Contributor
timestamp: December 25, 2016, 10:45:17 pm
content: Thanks for all the feedback guys, a huge thanks!One last question before attempting it: If pre-heat the PCB to 120c, take it out and then turn it upside down to remove the solder with the soldering iron it's there any chance any mosfet or so can fall from the card? I'm asking this because the card will be hot and there may be a chance of that happening (??).Thanks once again.

author: rob77
author_rank: Super Contributor
timestamp: December 26, 2016, 12:05:26 am
content: Quote from: snowzord on December 25, 2016, 10:45:17 pmeven if you pre-heat to 150 celsius, nothing will fall off the board.i usually to it this way:1. put the board facing capacitor down2. pre-heat whole board with hot air (do not exceed 160-170 celsius - check with thermometer)3. continue heating with hot air , but the capacitor only - set hot air to 260-280celsius4. touch the leads of the cap with soldering iron5. thanks to gravity the cap will fall off the board