New build - Link meter problems


 
Do you have 3.3v on the output of the 3.3v regulator? It sounds like you either currently have a short somewhere on the 3.3v line, or have blown the 3.3v regulator (by shorting out the 3.3v line somewhere), or perhaps have a wrong component soldered in somewhere
 
I tested the 3.3v reg and one leg has 12v the other doesn't get much reading at all. I just placed an order with digikey for a replacement part.
 
The 3.3V reg should only get a 5V input!

Just to be sure, the 3.3V reg looks like this:
medium-MCP1700-TO-92-3.png
 
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Yeah, I just checked again the 3.3v reg is in IC4 right?

I checked again on the voltage and the center is reading 5v. The the other leg is reading about 1.4v and then the last leg is ground.
 
That 1.4V should be 3.3, this can mean 2 things;

1) Your MCP1700 is dead and needs to be replaced.

2) There is a short circuit somewere.
 
Peter is right, it's 1 or 2...

If you can pull the output leg of the 3.3V regulator out of the board you can see if it jumps up to 3.3vDC and know whether it's scenario 1 or 2 you are dealing with. Keep in mind scenario 2 can lead to scenario 1, so you might have both.

If you have a short somewhere and you do not clear it up before you put the new 3.3v regulator in you might blow the new one up the instant you power it up. The 3.3v regulators are cheap, so I hope you ordered a couple in case you take another out in the process of figuring out what is going on here.
 
Thanks for the info. I really appreciate all the help and information everyone has provided so far.

I did order 2 new 3.3v regulators.

When you say to take out the output leg does that mean I have to keep in the ground and 5v legs somehow and just pull out the 3.3v? My replacement parts are out for delivery and should be at my house when I get home tonight.
 
What I mean is, a simple way to test the 3.3v regulator is to isolate the 3.3v output leg while the gnd and input legs are connected (by whatever means). If you have 3.3VDC on the output leg while isolated then your 3.3v regulator is good. However, if you put gnd and +5VDC in and you are not getting 3.3v out the output leg then the regulator is toast.

IF your 3.3v regulator is toast then you have to wonder, did it fry during a momentary short circuit (like you set the HM board on something metal and shorted it out long enough to fry the regulator), or is there a short on the board (still) that will kill the new 3.3v regulator the instant you power it up in the board?
 
So I replaced the BS-170 that was bent over and had the long leads, I removed the 10k resistor that was mentioned much earlier in the thread as not needed on my setup because I have the thermocouple, and finally and most important I replaced the 3.3v regulator.

I only had time to boot the board and let it run for ~30 seconds but it seems to be working. It turned on, I have LCD backlight again and the LCD readout said "No pit probe". I'm also running without the RasPi, so when I get home I'll pair it up again and plug in some probes just to verify. I'm pretty excited as I plan to do some cooking on Saturday and it will be great to have my heatermeter controlling the cook!
 
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Last night I paired up the RasPi and also plugged in my thermocouple. Everything is running great. Thanks again for all the help everyone! I let it run on my desk for a few hours last night just to be sure everything was working well.

I'm planning to do a pork but tomorrow on my UDS so we'll see how she does then.
 
That's awesome! Glad to hear it got all worked out. It sometimes feels like voodoo when this stuff works (or doesn't) but it is nice when you can look at a part and say "this is definitely bad", replace it, and everything works perfectly. Gives you that feeling that you know what you're doing! Enjoy the cook this weekend.
 
Yeah, I have to say it feels great to have it all working.

I thought I saw a thread on here were people were posting about their working heatermeter builds to track how many were "in the wild" but now I can't find it.
 
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