Got this CG Tristar yesterday. Testing it was not successful as the control know was not moving. After some gentle "persuation" on the knob something broke and it now spins freely, but does not engage the valve control. I assume there is a plastic catch in there that engages the valve spindle which broke, but I am unable to the knob off. The knob is in two pieces; a top-most tabbed piece which appears to be held down by some metal inside. Then the sleeve with the printed numbers appears to be attached to the tabbed piece. Neither are moving. Anyone taken this knob apart? I'd love to remove it without completely wrecking it.
Disregard. I figured it out. There was no clean way other than to press a screwdriver in between the sleeve and the top knob, and pry it off.
Here's the final diagnosis: broken. There is also an easier way to get the cap off I just realized. The manufacturer likely had/has a little key that would be inserted into the 4 holes at the top of the knob, releases the catches. That was not a metal washer. Once inside we see the valve control. I consists of a plunger mechanism that was fully seized up by old lubricant. I cleaned off the cruddy lube as best I could and smeared some reel grease on it. The plunger presses on a spring which I assume presses on a schrader valve underneath it all. I tested the plunger and it passed gas as expected. However, when I reassembled the knob, nothing happened. We can see the steps on the inside of the cap, so why is it not working (besides the fact that everytime I prize off the cap I chip off a chunk of plastic)? Well, there's nothing on the plunger for it to catch. Upon closer inspection of the plunger piece I can see where a part has broken off. There would have been some tabs on the outside of the plunger. Probably the "snap" i heard when I initially tried to turn the knob. The plunger was stuck and the puny, aged tabs didn't stand much of a chance. Only way this will be fixed is with a new plunger piece or to fabricate a whole new control knob.
For posterity, in case anyone else has the misfortune of having to perform this particular repair; I have won this battle. I ended up having to fabricate a replacement for this part. The original has two wings/tabs broken off. I tried to commission one to be 3D printed, but wasn't having much luck. So I worked in parallel on a metal fabricated replacement. After a couple of failed attempts, I landed on this production. It consists of a 7/16" brass tube, some bits I cut from a Coleman lantern pump stem for the tabs, and a decorative faucet knob screw cap (which fit perfectly!) for the cap. Once that was all soldered together I just had to make a few adjustments and its back off on its way. The real trick was accommodating 2 different diameter springs for the engagement of the Schrader valve. I may work on a nicer one in my "spare" time, but this one is serviceable. I can't discern any difference between 2 and 3, but 1 has a nice simmer and 2/3 will definitely boil.
Thanks! Unfortunately this stove will have a short lifespan. They don't have much resale value, especially with the repair, and its usefulness to me will be limited to the remainder of whats in the tank (very little), plus a full spare. But I enjoyed the repair and will relish the win.
Just got one of these in a auction lot of camping stuff ($3!) and sure enough knob it quite stuck. This post is going to help a lot! Not that I NEED another stove, but just can't stand having something not working and I'm not gonna throw it away, besides, got a bunch of canisters with it.
Nice! Assuming you have a fuel supply they are great burners. The key here is , if it’s stuck, don’t attempt to turn the knob. Focus on removing it and clean every bit of old grease out from the plunger assembly and you should be good to go.
I have one somewhere, mine has no simmer and settings appear to be inferno , incinerate and the interior of the sun.
