Thermoworks Pro-Series High Temp Straight (TX-1004X-SP) Isolation Issue

[Joel K]

Just curious if anyone else has experience this. I have both the right angle bend (TX-1001X-OP) Thermoworks thermistor probe, and the Straight (TX-1004X-SP) thermistor probe on a Heatermeter v4.3 with a thermocouple (using a Thermoworks Hight Temp Air probe, TW-113-442-GC).

I have no problems using the right angle probe and the thermocouple air probe together. However, if I use the straight probe, and any portion of its outer braid comes in contact with the thermocouple probe's braid, I get erratic temperatures for both the thermistor straight probe and the thermocouple air probe. I did some searching on the forum, but I didn't find any other references to this issue, so I thought I'd create this post.

Here in the image, you can see all three probes reading the same ambient temperature. Then when the outer braid of the straight probe touches the thermocouple probe's braid, the readings go through the roof.

 

[RalphTrimble]

This issue had surfaced with certain Maverick probes but I've never heard about it with Thermoworks. I know the maverick probes in question used only one internal wire and used the braid for the ground. I'm pretty sure TW probes all have two wires inside the braid. I would suggest you reflow solder on the components associated with the probes in question, including the probe jacks, then wash the board with isopropyl alcohol and a soft brush (make sure you let the board dry completely before you power it up)
Out of curiosity you might check the braid on both probes for continuity to the ground on it's plug to see if there is a difference there between the problem probe and the one that doesn't present the problem.

 

[Joel K]

I took another look tonight. I was able to test continuity on the straight TX-1004X-SP probe, and not on the curved TX-1001X-OP, which lines up with the results I experienced above. However, I thought I had the same issue with the replacement straight TX-1004X-SP Thermoworks sent me, but that is not the case. I could not measure continuity on the replacement, and repeating my tests with the replacement probe did not have the same issue as my initial post. So it looks like the first straight TX-1004X-SP probe I received was just faulty and there's not some wider isolation issue with the Pro straight probe line.