JD Siegrist
New member
so I finally did some back tracking on mine. Turns out I was using 1/4w resistors, and after I desoldered them off, sure enough the came out to be 22k still. Its just so strange...
the whole story is that during testing and the build, my temp probes tracked out perfectly. During the 'test run' they tracked out perfectly as far as I could tell.
Then on the maiden voyage, I noticed they were off by about 10*. I adjusted and proceeded with the cook, but for some reason as the cook went on, the gap widened to the point where 10 hours later they were 40* off.
I agree with Brian that measuring stuff in circuit is tricky at best. What I figured is that whatever I measured on the PIT line, I should measure the same thing on my PROBE1 line. Whether its voltage across the resistor, voltage before the resistor, etc. they were NOT the same.
So I desoldered them and verified everything, and it all checked out. So then I put everything back together again, and gosh darn it the temp probes were accurate again.
So then it sat for about 2 weeks and I'm planning to give it another go... tonight i decided to check on the accuracy, and now I'm 10* off again :-(
Going on a dry run tonight to see what happens. I have a diff q for those of you that have one built. What is your measured voltage across the 22k resistors when the system is live? Also, if you don't plug in all your probes, does it affect the ones that are plugged in? For example if I leave my PROBE1 unhooked (but not grounded) I get a super funky reading on my PIT temp (even though that one is hooked up fine).
I gotta figure out whats going on, the easter brisky depends on it!
the whole story is that during testing and the build, my temp probes tracked out perfectly. During the 'test run' they tracked out perfectly as far as I could tell.
Then on the maiden voyage, I noticed they were off by about 10*. I adjusted and proceeded with the cook, but for some reason as the cook went on, the gap widened to the point where 10 hours later they were 40* off.
I agree with Brian that measuring stuff in circuit is tricky at best. What I figured is that whatever I measured on the PIT line, I should measure the same thing on my PROBE1 line. Whether its voltage across the resistor, voltage before the resistor, etc. they were NOT the same.
So I desoldered them and verified everything, and it all checked out. So then I put everything back together again, and gosh darn it the temp probes were accurate again.
So then it sat for about 2 weeks and I'm planning to give it another go... tonight i decided to check on the accuracy, and now I'm 10* off again :-(
Going on a dry run tonight to see what happens. I have a diff q for those of you that have one built. What is your measured voltage across the 22k resistors when the system is live? Also, if you don't plug in all your probes, does it affect the ones that are plugged in? For example if I leave my PROBE1 unhooked (but not grounded) I get a super funky reading on my PIT temp (even though that one is hooked up fine).
I gotta figure out whats going on, the easter brisky depends on it!