Yihua 908D soldering iron seems to have given up the ghost. - Page 1
Forum section: electronics / repair

author: KaoDome
author_rank: Newbie
timestamp: November 26, 2018, 09:38:28 pm
content: Hi everyone, so today I was about to solder something when I realized my soldering iron acts up. It's out of warranty for a couple of months, but I had only used it for 4-5 times over its life, so I'm kind of bummed that it doesn't work anymore.When connected to the mains voltage and turned on, the 7 segment display and the heater LED light up for a fraction of a second and then turn off, repeating this cycle indefinitely. It's not able to heat up this way (in a reasonable time anyway), so it's useless as of now.I decided to open it up, in the hope of finding some component that needed replacement. It doesn't smell like burned electronics, and there's nothing evidently broken in there to me; but I barely know the components that make up the circuit since I'm just beginning with electronics, much less the circuit at this point. Besides, there's a microcontroller in there, an S3F94C4 so it complicates things.I don't own any other soldering iron to desolder or replace components, but I could get access to one (I do have a multimeter, but no scope either). How would one go about repairing something like this anyway? I am thinking about going through the traces and try to reconstruct the circuit, and then see what's up. Would it even be worth it anyway? I spent around 30 bucks when I got it, which isn't much, but it's significant for me.I'm attaching a couple of images in case anybody more experienced is able to see something I don't, thanks anyway for the time and the advice on how to procede.

author: Armadillo
author_rank: Super Contributor
timestamp: November 26, 2018, 10:00:02 pm
content: Can you take this photo close up again?

author: KaoDome
author_rank: Newbie
timestamp: November 26, 2018, 10:57:29 pm
content: I couldn't focus it cleanly right now, but that seems to be the problem, that leg of the (smoothing? ripple filtering?) capacitor is lose. I'll solder it properly tomorrow, but I made sure it was touching the board before plugging it in and it works as expected now. Thank you very much!I'll make sure to clean up the board too, that area has some yellow-brown-ish deposits as if it were corrosion, but I'm thinking it could be some flux residue, it has certainly not been near water while in my possession.

author: oventech
author_rank: Contributor
timestamp: November 27, 2018, 02:34:38 am
content: Bad soldering, mistake totally missed by assembler,QA. Resolder that point. clean the PCB with IPA. Clean both sides of the board. Reassemble and use it. Good luck.

author: perieanuo
author_rank: Frequent Contributor
timestamp: November 27, 2018, 10:10:44 am
content: Ha ha, needs a solder iron to repair the solder ironEnvoyé de mon iPad en utilisant Tapatalk

author: Rasz
author_rank: Super Contributor
timestamp: November 27, 2018, 11:14:44 am
content: Quote from: perieanuo on November 27, 2018, 10:10:44 amof course. buy cheap, buy twice

author: bd139
author_rank: Super Contributor
timestamp: November 27, 2018, 11:33:28 am
content: This doesn't surprise me. I remember when I had an equally shitty Aoyue iron. The element went pop. So I tore the iron down and realised I needed a damn soldering iron to replace the element. So I bought an Antex XS25 and used that to fix the Aoyue. Then I thought "hey this Antex firestick is less shit" and just used that.Also I recommended one of those T12 irons to someone a couple of weeks back. I said "buy the assembled one". What did he do? Bought the bloody kit so guess who has to assemble that because he doesn't have a soldering iron

author: stj
author_rank: Super Contributor
timestamp: November 29, 2018, 01:09:27 pm
content: now that's funny, buying a kit when he didnt have an iron!!is he an idiot, or just very devious?? i would charge him the difference in cost between the kit & assembled version to build it.

author: bd139
author_rank: Super Contributor
timestamp: November 29, 2018, 01:10:48 pm
content: He’s definitely an idiot. I am just avoiding him now

author: mnementh
author_rank: Super Contributor
timestamp: November 29, 2018, 05:56:25 pm
content: What you do is you tell him to drop off the kit so you can tell him what it needs to be assembled.THEN you avoid him.mnemLike the plague...

author: bd139
author_rank: Super Contributor
timestamp: November 29, 2018, 07:49:09 pm
content: He’s got the kit. Had three SMS messages today inviting me over on Saturday for dinner. The sociopath in me wants to go because the food is always good and just forget the soldering iron

author: mnementh
author_rank: Super Contributor
timestamp: November 29, 2018, 11:06:31 pm
content: Well, speaking as someone who routinely cooks for a family of 2-20 (depending on how many of my two children are home) , I can say with some degree of conviction that the level of assache involved is probably worth right around 2 good meals, or one VERY good meal. As long as someone else cleans up afterwards. Of course, I've got a fair amount of experience building these now, and it probably wouldn't take me more than half an hour or so... and I'd still let him screw everything together once I'd got it soldered up and working.mnemI am not my pants. No, I am not your pants either.

author: stj
author_rank: Super Contributor
timestamp: November 30, 2018, 01:14:05 pm
content: Quote from: bd139 on November 29, 2018, 07:49:09 pmgo over, and leave your irons at home.

author: mnementh
author_rank: Super Contributor
timestamp: November 30, 2018, 07:05:19 pm
content: bd's way ahead of you...Quote from: bd139 on November 29, 2018, 07:49:09 pmmnem*Waiting for the Electrician or Someone Like Him*

author: bd139
author_rank: Super Contributor
timestamp: November 30, 2018, 07:27:22 pm
content: I’ve decided to actually help seeing as I’m getting slow cooked ribs

author: GreyWoolfe
author_rank: Unknown
timestamp: November 30, 2018, 09:12:57 pm
content: Quote from: bd139 on November 30, 2018, 07:27:22 pmI would do it for slow cooked ribs, especially if there is home made potato salad and cole slaw. And beer. But after the soldering.

author: bd139
author_rank: Super Contributor
timestamp: November 30, 2018, 09:16:11 pm
content: Beer is good for soldering. Helps counteract the shakes from the coffee

author: GreyWoolfe
author_rank: Unknown
timestamp: December 01, 2018, 01:29:00 am
content: I don't really drink coffee so the beer might give me the shakes.

author: mnementh
author_rank: Super Contributor
timestamp: December 01, 2018, 04:04:43 am
content: Quote from: bd139 on November 30, 2018, 07:27:22 pmQuote from: mnementh on November 29, 2018, 11:06:31 pmIt would appear that your "price" is very similar to my own.mnem*Always willing to prostitute my genius for the right combination of food and friendship*

author: bd139
author_rank: Super Contributor
timestamp: December 01, 2018, 10:00:06 am
content: Indeed it isEdit: paid with ribs. Was a worthy meal for the job. I’m happy.