thermo

So, I finally broke down at Target and spent the 15  bucks on a thermometer with a corded thermocouple so that I could monitor the internal temperature  of things in the oven. It features a removable cable with a two-conductor phono jack, presumably for the purposes of cleaning it.

It’s a nice little sans-frills unit from a company called Taylor.

We got around to using it the other night on a meat-loaf, only to have it have a weird readout:

Weird Readout

The readout would flicker between ‘LLL’ and the actual temperature as I twisted the connector round and round in the plug. I could get it to stay, but as soon as I turned away from it, it went back to ‘LLL’ – making the alarm feature worthless.

Not that I’ve ever had a problem returning anything to Target, but I wasn’t really ready to put up with the hassle of taking it back – besides, I needed it to work THEN, not two days from then! I said to myself: “I can fix this, I’ve worked several jobs [as an audio technician] fixing just these types of problems!”

So I took it into the office and fired up the soldering iron – I basically assumed that I was going to have to cut the connector off the thermocouple and solder it directly to the PCB. To hell with being able to disconnect it…

Once I got it apart and took a closer look, I began to wonder if the jack was the actual problem… it seemed sturdy enough.

Cable and jack

Partly out of curiosity, partly out of ‘this wire seems extraordinarily loose’, I took the display portion completely out of the housing (BTW – SIX screws to hold the PCB to the housing?! It’s only two square inches!)

So, once flipped over, the problem was annoyingly obvious:

The problem

The caption says “No Solder Here”  Seriously – possibly the most critical solder connection for a thermocouple based thermostat (The connection to the thermocouple) was not even soldered! It hadn’t just broken, it hadn’t cracked, it wasn’t insufficiently soldered – it was never soldered!

So, a few seconds later, it was fixed. And I didn’t have to connect the wire directly onto the PCB – I can still unplug it if necessary.

I wonder if I broke the warranty…

Thermometer Fixed