View Full Version : my first hobart

12-08-2010, 02:00 AM
so i picked up a hobart handler 120 the other day for $85 with a smith co2 regulator and a 20lb steel co2 cylinder. the catch is the welder doesn't work. the guy's kid brother used it on max settings for 30 min straight. this slightly melted the insulation on the mig gun wires near the connections under the cover. on top of the insulation damage the diodes are fried. new ones should be here next week.
diode replacement looks pretty straight forward. bolt to the plate and solder the wires on. any tips on other things to expect to be bad with such a severe overheating? i need to figure out how to test any protective switches that should have stopped it from overheating.

12-09-2010, 12:30 AM
No thermostats in your welder. It is up to the operator to watch the duty cycle limits.
and not over heat the welder. You will need to look at the output inductor and make sure it is not burnt or melted. same with the weld transformer. When soldering your diodes yous ahot iron and short melt time. an alligator clip on the diode terminal will help protect it while soldering. When the diodes are disconnected tape up the wires. Then power up the welder and pull the gun trigger. Make sure the transformer has AC power out and doesn't hum real loud. This would indicate a problem with it. almost no noise is good. The inductor you test by welding. Nice normal arc and we are good to go. Having a hard time keeping the arc going. and having it go out right after starting. could be a bad inductor.
hopefully it just the diodes and it will work fine after you install them.

12-11-2010, 03:45 PM
I have a hobart handler 120, and I can tell you that is does have some type of duty limiter as mine kicked out one 90 degree day while I was using it on max. After 20 minutes, it restarted fine. good luck Hkstwn7

12-13-2010, 01:32 AM
That's about 17 minuets past the duty cycle limit. All duty cycle are based on a ten minuet time period. 20% duty cycle is 2 minuets on 8 minuets off. Most welders are not run at max output. Which gives a little longer weld time.
Only the CSA model has a circuit breaker in the primary circuit. according to the diagrams there are no thermostats. Watch yor weld times and give the welder a cool of break every few minuets.

12-17-2010, 03:19 AM
minuets you say ccawgc, don't those bach ones last like 10 minutes each, x's 8 would make for long breaks. lol.

but on a good note the diodes came in and she is alive. took 20 minutes to install and away it goes.

12-21-2010, 11:33 PM
Duty cycle is limit used a set amp and volt setting.
A larger roll around 200 amp welder will have a 60% duty cycle. That's at 200 amp and 28 volts. But if I keep my output around 135 amps and 18 volts, I get a 100% duty cycle.
The limits on a welder change based on how it is used. 15 seconds on and 15 seconds off equals a 50% duty cycle.
These small welders are not production welders. They are for small jobs that allow for cool down time. You will get more welding time with smaller wire, because they need less voltage and current to weld with.