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Harbor Freight Auto-Darkening Solar Welding Helmet Repair

by on Sep.26, 2011, under Tutorials

A little over a year ago, I purchased one of Harbor Freight’s auto-darkening welding helmets.  For $50, it’s a great deal.

helmet1

Unfortunately, after less than a year of use, it simply stopped working.  Somewhat ironically, the way you find out that your helmet has stopped working is by getting a flash burn in your eyes when you weld using a broken helmet.

One of the guys in my welding class mentioned that there are batteries in the helmet which can go bad over time.  Batteries in a solar-powered helmet?  Clearly this guy was nuts — but I thought I’d check it out anyway.

Turns out, he wasn’t crazy.  There are two CR2330 coin cells soldered directly to the main circuit board inside of the unit:

batteryChecking the batteries with my voltmeter, I quickly discovered that one of them was completely dead.  The other battery was still putting out a solid 3VDC.

Since soldering in batteries every time they go dead is not exactly a user-friendly solution, I decided to replace them with AAA’s.  Here’s the procedure.

1)  Remove the darkness adjustment knob by gently prying it off with a screwdriver.  Un-screw the plastic nut which holds the unit in place.

2)  Remove the clear plastic shield from the front of the helmet, and then gently remove the electronics assembly by unhooking the retaining spring.

3)  Use a utility knife to pop open one corner of the enclosure.  Work your way around the circumference with a screwdriver, breaking apart the plastic weld, until the cover can be removed.

4) Mark the locations of the (+) and (-) of each coin cell.  Using your desoldering braid, remove the coin cells.

5)  Go to Radio Shack and buy two AAA battery holders.  I used these:

batt-holder

6)  Solder one AAA holder in place of each of the coin cells that you removed.  Be sure to observe polarity.

solder wires in

2holders

7)  Using the shaft of your soldering iron, melt a hole in the side of the enclosure so that the wires from the battery holders can exit.  You’ll also want to melt a corresponding hole in the cover.

8)  Mix up some 2-part epoxy, and epoxy the wires to the enclosure.  This step probably is not necessary, but I don’t want to burn my eyeballs again.

epoxy

9) Wait for the epoxy to dry.  Take this opportunity to clean all the viewing windows with Windex and a lint-free cloth, then  reassemble the unit.  There are four friction pins which seem to hold everything together just fine.

reassemble

10)   Re-install the electronics housing into the helmet.  Re-attach the darkness adjustment dial.

11)  Glue the two AAA holders to the inside of the helmet.  I initially used the same epoxy that I used to hold the wires in place, but it didn’t bond to either the plastic of the helmet or the plastic in the battery holders.  I ended up using my hot glue gun, which worked very well.

glue

glue2

12)   Install four AAA batteries, and then test your helmet.  I found – quite by accident – that the helmet will darken when you look at a halogen light bulb.

13)  Go weld stuff.

Good luck with your repair!

~Eric

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