Help Repairing Weller WR3M Soldering Station - Page 1
Forum section: electronics / repair

author: deandadnaed
author_rank: Contributor
timestamp: March 14, 2019, 02:45:05 am
content: Hi everyone!A couple of days ago I made a terrible mistake.I have a Weller WR3M soldering station. The air pump wasn’t working since I bought it. So I thought I could inspect what the problem was and solve it.However. I made a mistake and now the station doesn’t work at all.By mistake I plugged the Air Pump (24V CC) to the plugs in the board of the Vacuum Pump (12.5 V CC). After doing that the soldering station stopped working.Here are some images.Visual inspection reveals nothing wrong (I think). The fuse wasn’t blown. Nothing seems burned. Still it doesn’t turn on. When I plug it, and turn on the switch I hear a little buzz and that’s all.Any help is really appreciated. I really like this soldering station. It has been with me for a while and I really want to get it back working.Thank you!Enviado desde mi iPhone utilizando Tapatalk

author: mahi
author_rank: Regular Contributor
timestamp: March 14, 2019, 05:23:02 pm
content: When you speak ofthe fuse, do you mean the primary fuse at the back of the unit or the 2 secondary fuses on the PCB (the brown and black thingies next to the big grey connector)?

author: deandadnaed
author_rank: Contributor
timestamp: March 14, 2019, 05:28:20 pm
content: The fuse I checked was the main one at the back of the unit.In this picture is right below the ground signal and the yellow/green cable.Enviado desde mi iPhone utilizando Tapatalk

author: deandadnaed
author_rank: Contributor
timestamp: March 14, 2019, 05:34:26 pm
content: How can I check the fuses on the PCB?It’s the one that says “MST T3 15A/250V” (black) and the other says “T1 6A/250V” (brown).Should I check them for continuity?Enviado desde mi iPhone utilizando Tapatalk

author: helius
author_rank: Super Contributor
timestamp: March 14, 2019, 06:30:08 pm
content: You can use your DMM in resistance mode and probe both ends of a fuse. If it reads below 1 ohm, it's good. Anything above that and the fuse is blown (there may be a path in the remainder of the circuit that provides a non-infinite resistance, but a working fuse is always less than 1 ohm, usually much less).

author: deandadnaed
author_rank: Contributor
timestamp: March 14, 2019, 06:44:28 pm
content: Quote from: helius on March 14, 2019, 06:30:08 pmI’ll do that. And I’ll post the results.Thank you very much!Enviado desde mi iPhone utilizando Tapatalk

author: deandadnaed
author_rank: Contributor
timestamp: March 14, 2019, 07:06:05 pm
content: Quote from: helius on March 14, 2019, 06:30:08 pmI’ve opened the case and measured the resistance of the fuses. Both give above 2 mega ohm of resistance.I think that given this results it’s for sure both fuses are blown up. I’ll replace them and see what happens.Anyway if there’s something else I can do, any advice will be appreciated.Enviado desde mi iPhone utilizando Tapatalk

author: deandadnaed
author_rank: Contributor
timestamp: March 14, 2019, 07:39:45 pm
content: I’ve tried “bridging” the fuses. And it’s correct. The Station does turn on.I’ll buy them and replace them. I know That’ll work.Thank you very much Helius!!!Enviado desde mi iPhone utilizando Tapatalk

author: juhuhu
author_rank: Newbie
timestamp: November 11, 2019, 01:53:15 pm
content: deandadnaed Do you have maybe high resolution pictures of the main circuit board of this station? If yes, could you send me in PM. I have one on the table for repair and need some burned components info.Thanks.

author: SB
author_rank: Newbie
timestamp: January 13, 2020, 06:20:49 am
content: Dear Juhuhu;Did you get a high resolution picture of WR3M board? If no, kindly let me know. I could send you the picture.If yes , did you repair your damaged WR3M ?Thanks a lot.RgegardsSaeed(Mr).

author: Brycharlie
author_rank: Newbie
timestamp: June 02, 2024, 09:34:24 pm
content: Would it be possible for me to get those images? I'm currently working on one of these. I'd also appreciate photos of the internals of the unit in general. Thank you!B.C.

author: mkinn
author_rank: Contributor
timestamp: May 31, 2025, 05:54:12 pm
content: I'd also like to ask you for a High-res photo of that main (output) board. Also, if anyone has a schematic for a WR3M or WR3ME, mine just had a short on ch 1, stays on even after temp is reached, will destroy an iron connected to it if I don't shut it off right away. Iron glows red hot! Hoping it's a shorted output trs. The green LED comes on immediately when an iron is plugged in, never goes out.

author: pamihai
author_rank: Newbie
timestamp: September 25, 2025, 01:42:12 pm
content: hi,I know it is an old post but want ask you SB if you still have high resolution pictures of the main board from Weller wr3?thank you