If the charger doesn't work but the main unit does work, the two usual
culplrits are a bad contact on the selection switch or a blown diode.

In most electronic equipment, switches are not much of a problem but
welders tend to have high currents, dirt, open design, and not high
useage of the switch. Look for cruddy contacts, buff them lightly with
some soft abrasive (NOT steel wool!) and see what goes.

Simple ohm meter check from both directions shouls spot a bad diode.

Odds are good you could find the culprit in half an hour of open case
diagnostics.

Christopher Tidy wrote:
Hi all,

My welding set contains a 75 amp battery charger, but it doesn't work.
I'd like to fix the battery charger so I can use it for electrolytic
de-rusting and electroplating, but I'd rather not pay for the welding
supply shop to fix it.

The welding set is a Cytringan Bantam 180 amp oil-cooled AC set. I don't
have the digital camera to hand, but it looks very similar to the
Cytrigan set shown at the top of this page, just a little smaller:

http://www.johndavies.co.uk/uarc.htm

I can take a photograph later if necessary.

My question is, does anyone know what I can expect to find if I open the
welding set, and what the problem might be? I'm assuming the battery
charger uses a single diode to produce half-wave rectified DC. You can
adjust the battery charger current using the same knob used to adjust
the welding current, but the charger current apparently only reaches
about half the welding current. There is a separate terminal for the
battery negative, and you connect the battery positive to the welding
earth. Even with no load, there is no voltage measurable between these
terminals.

I'm guessing that there's a dud diode or loose connection inside. I hope
there's nothing wrong with the transformer (it welds fine). Anyone know
what I might find inside the set, and what the problem might be?

Best wishes,

Chris

PS: Got some 6011 rods on Monday. Will try them this weekend.