Figured it was time to get a lead thermometer.
Bought a Lyman electronic thermometer off amazon last week. It arrived next day.
Fired up my old lee pot. Put a battery in the thermometer, turned it on and it is stuck at -75 degrees. No reaction when the probe is placed in the molten lead. Bummer!
Was going to return it to amazon but inside the paperwork supplied with the lyman there is a note stating if defective do not contact the retailer, call or write lyman for customer support.
So I sent them an email about the problem. Lyman replied asking for a receipt, sent them the receipt and a few days later a replacement arrived.
This one works just fine! Great customer service in my opinion! Would probably be still waiting on amazon to figure out what to do.
So got fiddling with the defective unit, the probe works fine on the new unit, new probe on bad unit no worky! Took the unit apart, surface mount electronics, not much to the circuit board.
I found by putting pressure on the circuit board underneath the lcd screen the thermometer would come to life and work fine until you removed the pressure. I placed a small rubber shim under the bottom frame of the screen and it worked fine for about ten minuets then back to -75.
I removed the lcd from the board (2 screws), cleaned its traces and the board. Then noticed the circuit board is warped like a bow where the lcd screen makes contact with the board traces. So apparently the lcd is not making full contact with the board.
I heated up the board in that area while applying pressure to it to remove the bow in the board. Reassembled it and worked fine for about 30 min then back to -75 again. Pulled it apart and the boards still straight, so now I'm guessing there's a bad solder joint on one of those three resistors that are mounted under the lcd. China is known for bad solder joints! If the lcd did not cover those I could pinpoint the bad joint.
I have a surface mount soldering iron, just no magnifying glass, so until I find one this will go into the pile that needs to be fixed someday! LOL
Hats off to Lyman customer service!
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