Heatermeter temperature dies during cook....


 

MartinB

TVWBB All-Star
So I'm in the middle of a brisket cook
Everything is good
I take my wife's little dog out for a walk and come back
And I noticed I had a temperature Spike of 20 degrees on the thermistor probe in the meat.

That don't look right.
Not to mention it's correlated with a spike on the thermocouple

So I pulled the probe out. It read 220 degrees in the ambient
Hooked it up to my Maverick, it works fine read ambient temperature
Plugged it back into the heater meter it reads 200 degrees.
Plugged it into a different heater meter plug that reads High also

Not to mention when I plug it back into the heater meter then the heater meter thermocouple reads like 300, unplug it reads normal, plug it back in the thermocouple reads 300+.

So what died in this heater meter and what do I need to replace?
Since I didn't build it, I bought it from Bryan, I'm a starting at Square One.

Also recall if you will that I've had noise on my thermocouple since day one swinging 1-2 F, if that's relevant

Thx

A second temp probe from the ready check reads a little bit lower than the heater meter thermocouple, but close enough that the heater meter seems to be reading right when no thermistor plug is plugged in.

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ppl
 
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I'd start with taking high quality pics of the PCB to see if you can zoom in and spot any corrosion, cold solder joints or solder bridges.

The circuit path from the thermistors to the microcontroller is pretty minimal. The thermocouple circuit is a bit more involved, but still not overly complicated.

You can take a bare wire or a thin paperclip and and insert it into the thermocouple jack (where you would normally plug in the thermocouple ) and it will force the thermocouple amp to use its own ambient temp as the reading. See if that reads ok. Try plugging in a thermistor and see if that changes things.
 
Well, fingers crossed, it work again.

It *might* been caused by temperature
It was hanging from handle of wsm, only slightly warm to touch, not hot. Just like many times before.

But after i moved HM away and cooler...plugged back in, .it works.

What really concerns me is the thermocouple reading very high when installed a thermistor probe, and not without one.

Is there a stated ambient temp operating limit for some of the ic's? At most it might have been 120F, no worse than being in sun.

???
 
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Also recall if you will that I've had noise on my thermocouple since day one swinging 1-2 F, if that's relevant
I recommended you install the noise-testing firmware, which I will recommend again. It is still fully-featured HeaterMeter so you can run it while doing a cook and see if when your temperatures go wonky if you're getting just a ton of noise that's throwing the reading off. That could be due to a weird power supply (either the mains supply or the power adapter), the thermocouple shielding feeding noise into the system, or a non-isolated thermocouple feeding voltage into/out of the system which would cause erroneous readings.
 

 

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