Unfortunately Sears changes suppliers over time but for a very long time they had Harris manufacture their welding torches/gauges, better said they were just rebranded Harris equipment.
I would suggest you just go to a good local weld supply house that does repair! They may be hard to find, or ask at your LWS where they send out their torches for repair, and find the guy that works on them. Once you do that it's a piece of cake since these experts know the whole history. I have a few such places in the houston area that repair torches and refurbish gauges and they are great for this kind of info. Don't go through Sears as you'll just pay them 3 times as much to send it to a local guy anyway.
jbman45
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