Heatermeter Aux. Thermocouple And two probe board V6.1(Final Version)


 
I just got my board today and I am a little confused on how to wire it up so that I can use the thermocouple and probes on the aux board. Is there a schematic and/or pictures for the HM v4.3.4 on how to wire it?
 
I hate that im bothering Ralph so much so ill bring the question here. I built a new rdtc board and i cant get the TC working. Fan servo and food probes all work. there is continuity betweek all the IC posts on the board, no shorts. I had to salvage a tc amp IC from an old rdtc board i had that i never got working years ago. mainly because i didnt wire it right. Is there a way to troubleshoot to see if this IC is in good condition? being that mouser is out of them, how can i get a new IC.


Edit: Ralph repsoneed to check the voltage regulator and the IC pins.... Did that everything looked fine. Now it recognizes the TC but started at 500 degree and slowly lowered to around 200.
 
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That chip is pretty darn small and I’ve struggled with a couple of them. One of them required a good scrubbing with a toothbrush and some isopropyl alcohol. My guess is that some of the flux from the solder was allowing voltage to reach places it shouldn’t. If you have a magnifying glass or a camera with a decent macro function, you can try taking a pic of the chip and inspect it for any excess solder or bridges.
 
With a lot of help from Ralph, I have tested a lot of things. Im thinking it might be a bad IC. And they are out of stock to test that. I'm thinking that because I took this on off of an old RDTC board I had from years back I could never get to work.
 
I've got a 4.3 board already built, does anyone have any instructions and possibly some pictures on the best way to tap the appropriate points?
 
On Page 8 of this thread someone posted my diagram of how to wire the RDTC to the HM board. It shows HMv4.2 board, works the same way on HMv4.3 board though.
 
RalphTrimble said:
On Page 8 of this thread someone posted my diagram of how to wire the RDTC to the HM board. It shows HMv4.2 board, works the same way on HMv4.3 board though.
Click to expand...

The 4.3 board has a spot for a header.. which I've covered with probe jacks. I'm looking for some suggestions on how to best sneak these on a completed board without messing it all up or losing existing functionality. I wish I had decided I'd like the option before I soldered the probes in place, I could have put the header on and trimmed it flush. Maybe added headers to the spare jack pins.
 
My mistake, I see that now. I think that makes it easier. Any suggestions for the best way to hide the switch and resistor, maybe a switch type I'm not thinking of?
 
Hide the switch? A hidden switch that you can't flip doesn't do much good!
If you're not going to flip the switch because you plan to only use the RDTC pit probe then just eliminate the switch and jumper from pin 7 through the 100k resistor for the pit probe... The 10K resistor can be omitted in this configuration.
 
Update and odd problem. The heatermeter receives a thermocouple temp from the rdtc board if I hold the rj45 Jack and physically rotate the end of the board near the thermocouple clockwise. Is there a test procedure that I can tell where the thermocouple signal is getting held up?
 
If you look at post 55 in this thread here I shared a color code diagram of what pins on the TC amp should be connected to what components. You can use a multimeter in continuity mode to test of they are connected or not... However, you may put enough pressure on them with the meter lead to make the circuit (like when you twist the board)
If the problem doesn't present itself by testing continuity I would suggest you carefully reflow the solder on resistors and caps first and see if that solves your problem, then reflow the tc IC as a last ditch effort. Use some sort of magnifying device when soldering these small parts if possible.
 
Thanks Ralph. I did find post 55 before I posted, and had continuity, but I will try a lighter touch to see if I missed something. I will also reflow and hopefully that will solve it.
 
Well, I tried retouching the resistors and capacitors, but the problem persisted. I finally did the last ditch effort and heated up the TC IC leads on the side next to the potentiometer. That worked. I now have readings even if I flex the board. It must have broken free when the board dragged against the body of the rd3 when I first tried assembling, flexing the circuit board. Unfortunately, the yellow test location under the pot is not available when the board is assembled, so I was not able to test continuity at those locations. Thank you, Ralph for your help and for you and John answering all of my questions by email as well.
 
You should be able to get at that yellow test spot from the other side of the board, but none the less, glad you got it suss'd out!
 
I need to build or get an RDTC board. After my first long burn (20 hours for a large pork butt) it's clear the HeaterMeter (at least the case) cannot take the Arizona heat. Event though I had an big beach umbrella covering the grill area, it started to warp - and it's not even July or August :-(. Aside from that the HeaterMeter 4.3 board and RD3 did an amazing job!

Looking at the Mouser it seems at least one of the parts is still on a very long back-order (Multilayer Ceramic Capacitors MLCC - SMD/SMT 0805 0.1uF 100volts Y5V 20%).

Are there alternate parts that can be used? I've got a good variable temp soldering iron, but the size of the components and my lack of recent soldering experience is giving me pause. Even better would be if I could get an assembled RDTC board from someone - is this still an option?

Thank you in advance - Richard
 
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