TIG welding machine with OK repairability rating? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: April 15, 2023, 04:24:38 am
content: What is a tig welding machine that has a OK repairability rating, i.e. parts that are not glued down, no insane high voltage PCB card arrays, etc?I know that Miller is horrid and should be avoided based on reviews unless you have bloated department money that you need to spend and get your company sucked into service contracts because of internal arcing, non cleanable design, over heating parts that burn the PCB and parts choice that becomes obsolete in 2 years, but is anything OK, or is the entire industry like this?And with some design features like maybe a normal transformer for the control circuit rather then cascade failure set to blow switchmode flyback power supply chains.

author: Psi
author_rank: Super Contributor
timestamp: April 15, 2023, 04:46:07 am
content: Search for PDF service manuals/schematics for all the ones currently being sold and see what you can find.That is my number 1 requirement to find something worth getting. Then I look for reviews to check that modal is not shit.Then I check and see if replacement PCB boards are available.The really high end brands will be more reliable but also double the price of the cheaper china ones. So if you had to buy a 2nd one to fix a broken one you are still better off and have lots of spare parts.The TIG welder I got was a jasic wse200p, but that is old now, lots more new stuff that is better.Make sure you get one that can do adjustable frequency AC for doing aluminum. Some are fixed to 50hz and you really want adj up to at least 100hz, ideally 300HzOne failure mode of TIG welders that people don't consider is that- The device sits in a workshop- The device has large open grills down all sides for good airflow- Bits of metal and metal dust are flying around inside a workshop all the timeAll you need is one piece of metal to fly into the air grill and should a mosfet out and BANGMake sure you treat a TIG welder as the piece of gear it is, not something you can throw around and abuse like other tools in a workshop. Keeping a cover over it when not in use is a really good idea.

author: coppercone2
author_rank: Super Contributor
timestamp: April 15, 2023, 05:01:28 am
content: does any manufacturer provide component level diagrams?For instance, miller provides fake service manuals (if you read the testimonials, about 0% of users manage to fix their machines or even diagnose an issue by following this).Is anyone not balls deep in subassembly replacement scams, in case a $1 power resistor goes bad? Please replace 8 power transistors, 4 control ICs and 15 diodes because 1 resistor over heated due to a design oversight.

author: coppercone2
author_rank: Super Contributor
timestamp: April 15, 2023, 05:11:25 am
content: I am almost wondering if the knock offs are better then the 'brand name' units because the copy cats unfucked the deeply hidden MTBF parts 'time on target' attack by putting shitty parts in obvious places, and that the shitty parts are actually more available then some custom made slightly retuned rebadged transistors that the brand name ones likely have, and the design might be more flexible with replacement parts.Because I am thinking that its a fucking inverter, its not metrological grade cutting edge shit, it chops the fucking power grid to melt metal within the bounds of a god damn human hand, its just not that tuned. If it was for a robot, then I agree the copy cats would have a hard time, but its for a human operator, I am thinking there is only so much you can do with the electronics, there are too many unstable factors that the design should require ultra expensive electronics.I write this when I am contemplating taking a die grinder to capacitors on the miller PCB board. Lovely glue job between two heat sinks on 5 pin capacitors.Maybe I should just keep it all natural with the acetylene flame, no melanoma from UV from that shit, people have been living around high thermal radiation sources for a long time before the arc was invented.

author: Psi
author_rank: Super Contributor
timestamp: April 15, 2023, 06:33:17 am
content: If you do get a cheaper china one- Don't get the cheapest china one, get a more expensive china one.- Don't run it at 100% load, consider 80% your max.Sometimes if you can figure out who is actually making all the rebranded versions you can then buy that company's own brand. Which usually gets you a better quality unit.Usually the OEM will build it to the spec requested and this is often a lower price point so the quality suffers vs the OEM's own brand.The OEMs own brand is also usually been tested a lot more and the design has had time to mature.

author: Alti
author_rank: Frequent Contributor
timestamp: April 15, 2023, 07:53:21 am
content: TIG AC/DC or just basic TIG?My Kemppi Minarc Evo 150 is quite well built, there is a decentservice manualavailable from the manufacturer but this is not a very low level component level service manual. No custom parts (well, transformers and inductors), has screws but no glue. I use it as TIG lift, it also supports throttle pedal. It has conformal coating on a PCB but I guess that is necessary considering the environment.I second the opinion about spraying electronics with metal dust - buy 2x 3m of 25mm2 copper extension cable and put welder far from your activities.

author: jpanhalt
author_rank: Super Contributor
timestamp: April 15, 2023, 10:54:51 am
content: Quote from: coppercone2 on April 15, 2023, 05:01:28 amMy Miller AC/DC Tig with foot control came with schematics. Here are two more (I am too lazy to scan mine for evidence):https://www.millerwelds.com/files/owners-manuals/o1578_mil.pdfhttps://www.dropbox.com/sh/7ijbgx67wuq6ivd/AABgjByv5ShkF3L5riJj79mCa?preview=330+technical+manual.pdfThis is the 40th year I have had it and not a single problem. Presumably, you don't need a repair manual if the item never breaks.

author: coppercone2
author_rank: Super Contributor
timestamp: April 15, 2023, 03:53:00 pm
content: alright, if you can get schematics. I think thats their not miniaturized version.

author: jpanhalt
author_rank: Super Contributor
timestamp: April 15, 2023, 04:41:57 pm
content: Quote from: coppercone2 on April 15, 2023, 03:53:00 pmSpace is not a problem. I never go kayaking with my TIG welder.If you want something that repairable, don't get anything modern with a microcontroller for the on/off switch.

author: Gregg
author_rank: Super Contributor
timestamp: April 15, 2023, 05:22:16 pm
content: I have two older Thermal-Arc AC DC TIG welders and have schematics for both. Both are made in USA and have been ultra reliable.

author: coppercone2
author_rank: Super Contributor
timestamp: June 10, 2023, 06:27:44 pm
content: I decided to repost in this thread because the issue with the machine was solved after like a year.What I am saying to anyone here that might be attempting it and does not feel like searching for tons of threads to get the whole picture is that with this kind of machine you might find this1) multiple failures around various circuit boards2) boards that absolutely require replacement or very heavy repairs. I am saying like that the char areas are bad enough where in some places you can mill it out with a dremel and fill with epoxy, possibly replace a trace.. but there might be heavy damage that involves say.. remaking a 1.5x2 inch piece of PCB with lots of traces. That was my biggest hangup, I had a PCB that looked to my experience OK, but something was causing fets to sometimes melt/pop. I suspect it was contamination. I replaced the board because the amount of board area that needed fixing was high. I gave it a few go's replacing parts and... attempting more cleaning/repairs between the attempts, but it was just gobbling up parts.3) you need to be willing to pay for solvents/cleaners/coatings, that is there might be alot of degraded conformal coating on the PCB. I had to strip and recoat a few PCB.4) the non spray conformal coating can rework, the spray can will wrinkle the old coatings5) there is alot of 'iffy' stuff that you should fix like yellowed conformal coating that is a big pain in the ass.. because unless you just ignore degraded components, you will suddenly have ALOT of extra work.6) tons of cleaning, an old machine will have metal dust everywhere. It needs disassembly, washing and baking.

author: MadTux
author_rank: Frequent Contributor
timestamp: June 16, 2023, 11:22:49 pm
content: Stuff from europe:Old (gen 1/2) EWM and anything with it inside: utter garbage!Lorch IT G/GW (gen1) inverters: great repairability (lots of available 20-40$ Mosfets), but power rails on DC/AC stage too weak, put big copper bars there, and have fun for long time.Later Lorch V25/30/40... less simple construction and more integrated DC/AC stage, what makes them less repairable.ESS/Cloos Insquare: Simple and best HF start, IGBT modules might be difficult to get, if broken.Sweld (rare Swiss machine) is similar design/construction (half wave DC/AC converter), but without any microcontrollers.Fronius MW450: Beautiful construction but lots of custom parts and PLDsGYS stuff: lots of epoxyied PCBs and horrible to repair, from what I've heard so far.Chinesium TIG: Inside they are all the same, not too difficult to repair, but breaks down all the time.

author: Overspeed
author_rank: Frequent Contributor
timestamp: June 23, 2023, 08:00:19 am
content: HelloTig as all other welder shall be stored in a dry place , often they stay in shop cold / not heated and humidity generate catastrophic failureRegardsOS