How to Reflow a Board with Plastic Thru hole connectors? - Page 1
Forum section: electronics / repair

author: TheRuler8510
author_rank: Regular Contributor
timestamp: November 11, 2015, 02:05:44 am
content: Has anyone found a way to Reflow a Board containing plastic thru hole connectors without desoldering them?I'm thinking I can try to put layers of paper insulation around them, topped with aluminum foil, then reflow the whole board like normal?I have a reflow oven and I am looking for an easy way; reference Dave's video #762, where he melted plastic connectors.The subject board is a from a Smart TV only 1 year old.Regards,

author: Rasz
author_rank: Super Contributor
timestamp: November 11, 2015, 06:38:15 am
content: why do you want to reflow whole board? this suggests to me you dont know what you are doing (like Dave in that video :p)

author: TheRuler8510
author_rank: Regular Contributor
timestamp: November 12, 2015, 01:09:06 am
content: Yes, you are right; I was taking the easy way out, and probably not the best way.What is the next easiest thing to do? Is it a cheap hot air gun for SMD rework? What is the best model to get?Regards,

author: apelly
author_rank: Unknown
timestamp: November 12, 2015, 01:29:23 am
content: The cheap Chinese ones with the blower in the handle are ok. Surprisingly.

author: TheRuler8510
author_rank: Regular Contributor
timestamp: November 12, 2015, 01:42:12 am
content: What's a good example?

author: apelly
author_rank: Unknown
timestamp: November 12, 2015, 01:54:16 am
content: Can't remember where I got mine. Aliexpress I think. Dave reviewed one some time ago I think.Search on here for "hot air" for one of a boatload of threads.This ebay item might give you a starting point:http://www.ebay.com/itm/220V-700W-SMD-Rework-Solder-Station-Digital-Electronic-Hot-Air-Heat-Gun-868D-E64-/301614370242?hash=item46399e0dc2:g:UHkAAOSwrklVQeLv

author: Rasz
author_rank: Super Contributor
timestamp: November 12, 2015, 07:38:16 am
content: even if/when you get hotair, whats next? why do you think randomly heating the pcb will somehow magically fix it?lets start all overwhat is the product name? post a picture of the fault and picture of the pcb

author: TheRuler8510
author_rank: Regular Contributor
timestamp: November 15, 2015, 12:22:52 am
content: Quote from: Rasz on November 12, 2015, 07:38:16 amRasz,I was hoping for a quick fix. I realize reflowing the board is a longshot, but it is a dumpster-dive TV and I have nothing to loose. On other repair forums, there seems to be a lot of people that have gotten success that way.If a hot air tool has more chance of success, then I will try that. It would not be "random" reheating, but focus on the big BGA chips.Anyhow, what is the "proper" way? I'll post pictures in a few days. The TV does no go past the boot screen, people have said reflowing the main board is a good bet.Any input is appreciated.Regards,

author: Smith
author_rank: Frequent Contributor
timestamp: November 15, 2015, 10:59:11 am
content: Reflowing with a heatgun is not a problem. I've just repaired a DSO with a heatgun. There are a lot of reflow profiles to be found on google. You can use some thermocouple or IR thermometer to keep track on the temperature.If you have an oven or kitchen plate heater or somekind I would encourage you to preheat the PCB to about 100 degrees celsius. This greatly increases your change of succes. It also makes it easier to generate the needed temperatures, and the board and components have less of a thermal shock.

author: Aodhan145
author_rank: Frequent Contributor
timestamp: November 15, 2015, 01:31:59 pm
content: If you still want to do it in an oven. This is a bad idea. You can wrap it in a couple of things of cello tape then electrical tape then just cover it with a lot of tinfoil. Again very bad idea do it with a heat gun.

author: Smith
author_rank: Frequent Contributor
timestamp: November 15, 2015, 02:14:30 pm
content: Quote from: Aodhan145 on November 15, 2015, 01:31:59 pmCan you tell us why?

author: DaveCooks
author_rank: Newbie
timestamp: November 15, 2015, 03:38:14 pm
content: I'm fairly certain Aodhan means: "Again, very bad idea. Do it with a heat gun"

author: fivefish
author_rank: Frequent Contributor
timestamp: November 15, 2015, 04:39:30 pm
content: QuoteRemember not to use the oven for food preparation/cooking after you follow this advice.

author: Rasz
author_rank: Super Contributor
timestamp: November 15, 2015, 06:34:50 pm
content: stop giving him ideasThis thread is about a guy with broken car asking which hammer to use on the engine, because he saw someone equally as clueless do it on YT and fail

author: Aodhan145
author_rank: Frequent Contributor
timestamp: November 15, 2015, 09:33:42 pm
content: Quote from: DaveCooks on November 15, 2015, 03:38:14 pmYes I do, punctuation means everything. English is my first language and I can't use it properly.

author: Delta
author_rank: Super Contributor
timestamp: November 16, 2015, 03:04:00 am
content: Quote from: Rasz on November 15, 2015, 06:34:50 pmI think that's a bit harsh! The guy's just having a stab at fixing something that would otherwise be in a dump. It's got to be worth a try!

author: neslekkim
author_rank: Super Contributor
timestamp: November 16, 2015, 07:30:44 am
content: Quote from: TheRuler8510 on November 11, 2015, 02:05:44 amone year old?, what about warranty?

author: Smith
author_rank: Frequent Contributor
timestamp: November 16, 2015, 08:05:10 pm
content: My bad...You could use some pressure on the chips to find out which one has issues. Sometimes freeze spray makes it even easier to track them down.I don't know about warranty, but where I come from you need a receipt to claim your warranty.

author: neslekkim
author_rank: Super Contributor
timestamp: November 16, 2015, 10:03:12 pm
content: Quote from: Smith on November 16, 2015, 08:05:10 pmAh, didn't see that it was from an dumpster dive..

author: Rasz
author_rank: Super Contributor
timestamp: November 16, 2015, 10:40:03 pm
content: Quote from: Delta on November 16, 2015, 03:04:00 amIm all for fixing things, but nit with cargo cult thinking

author: Macbeth
author_rank: Super Contributor
timestamp: November 16, 2015, 11:55:01 pm
content: I have to admit any fix is probably only temporary, but if it keeps something out of landfill for a couple of months/years then why not? This isn't someone engineering something, this is someone trying something a few levels more than the usual "bang it a few times and she'll be alright!"Which by the way often does work. It's known as "Percussive maintenance" for a reason, not just because Dave jokes about it now and then.Having said that - just get a proper hot air source rather than an oven and use some common sense. Also get some liquid flux under the BGAs if you are trying to reflow them in situ. Underboard heating is a good idea too.If it fails at least you have some kit you can use in the future to unfail other stuff (and a donor board full of parts to stock!)