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Doall blade welder stops working

Knguyen

Cast Iron
Joined
Jun 16, 2003
Location
Bergen, NJ.
Dear gentlemen,
My doall band saw blade welder (DBW 1) was doing fine until today when I tried to weld a 3/4 " blade for my Horizontal band saw. Mounted the blade on the holders and pushed down the levers and nothing happened. I wonder if there is a fuse that was blown or it was a commonly encountered issue that can be resolved with simple maneuvers. Any input would be greatly appreciated . Thanks in advance.
Khanh
 
DoAll guarantees just about every thing they sell. Get a replacement. The one we had at work quit working because the ground had a bad connection. I cleaned it and it worked fine.
 
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I don't know how it is built, but there is a possibility that there could be a bad microswitch inside, so when you push the weld lever, its simply not closing the main relay anymore?
 
Yes, I would recommend you call DoAll and tell them you have a 40 year old device that has stopped working. They will be sure to just send you a new one.
 
Thanks, I did open the panel and looked behind the unit . Not sure if it has a fuse but a micro switch is possible. Nothing on no welding on trouble shoot section of doall. The thing is well built . Wonder if you can check for presence of electric current using a meter.
 
With the box open and the grinder powered up, get out your voltmeter and start tracing power from where it comes to the box all the way to the transformer. Probably you didn't blow the transformer. If a fuse blew then do NOT just jump it and try it again, that's how you really F something up.

When it goes from having power to no power you have isolated the problem.

Hopefully it is something simple like a switch's contacts needing cleaning.

metalmagpie
 
When was the last time you lubricated the moving blade mechanism? I've had mine stop working after 50 years and some oil was all it needed.
 
When was the last time you lubricated the moving blade mechanism? I've had mine stop working after 50 years and some oil was all it needed.

Mine also needed similar attention. It is a spring balanced mechanism that if parts get sluggish due to dried oil the slides hang up and do not make contact.
 
i have worked on many of these. I have seen WWII era welders with broken wires, but most of the time they just need a really good cleaning and TLC. the voltage is very low so any dirt will stop the current. Look at the face where they clamp the blade, it should be flat and clean, of not dress it up on a belt sander. this often is all that is needed to make it work like new.
 
Its already been said but its a resistance welder. Good electrical connections are a must. Even if the outside of a bolted connection looks good it can have pitting and arcing underneath. If you had thermal imaging you may be able to find the problem if its barely welding as a bad connection would have enough differential to be detected.

A bad connection can sometimes be improved in a pinch with some copper based anti-seize.
 
After a thorough cleaning, I checked also voltage across the transformer secondary output and there was none. There was voltage input from the primary. Conclusion: the transformer is fried. I am thinking of replacing the transformer or even rewiring it. Has any one any experience doing this? Thank
 
No, not at all. Would you suggest rewiring to replace the broken wire? which I think the way to go but my electrical skill is quite limited. Perhaps getting a replacement. The one from Doall quoted $1700!!!
 
I was going to guess $1700.oo but I did not want to sound negative, You might have luck taking it to a motor re-wind shop. I never had a transformer re-wound. The old wires get pretty brittle so if you are lucky maybe one broke out side the coil. clean it up and look at it carefully. DoAll 's re-placement parts are crazy expensive. About 20 years ago I got a quote on a ML table trunion , $1700.00. for a 5 pound iron casting. I had one made for about $250.00.
 








 
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