Garmin 330TXP temp probe pictures

[karl gruber[_1_]]

Some of you wanted to see the variable resistor in the line out to the temp
probe. As most have found, the probe does not transmit the proper temp. Here
they are:
"Curator"
http://temp.corvetteforum.net/c5/kgruber//cimg8787__medium_.jpg
http://temp.corvetteforum.net/c5/kgruber//cimg8788__medium_.jpg
http://temp.corvetteforum.net/c5/kgruber//cimg8789__medium_.jpg
http://temp.corvetteforum.net/c5/kgruber//cimg8790__medium_.jpg

[mikem]

karl gruber wrote:
> Some of you wanted to see the variable resistor in the line out to the temp
> probe. As most have found, the probe does not transmit the proper temp.

Karl,
I must have missed the earlier post. What is the issue with the OAT
probe?

[karl gruber[_1_]]

As supplied, it isn't calibrated.

Karl
"mikem" > wrote in message
ps.com...
>
> karl gruber wrote:
>> Some of you wanted to see the variable resistor in the line out to the
>> temp
>> probe. As most have found, the probe does not transmit the proper temp.
>
> Karl,
> I must have missed the earlier post. What is the issue with the OAT
> probe?
>

[Thomas Borchert]

Karl,

> Some of you wanted to see the variable resistor in the line out to the temp
> probe.
>

As I said in my mail to you already: Thanks a lot!

Do you happen to know any resistance values printed on the thing?

--
Thomas Borchert (EDDH)

[karl gruber[_1_]]

I'll ask Jack, next time I see him.

"Curator"



"Thomas Borchert" > wrote in message
...
> Karl,
>
>> Some of you wanted to see the variable resistor in the line out to the
>> temp
>> probe.
>>
>
> As I said in my mail to you already: Thanks a lot!
>
> Do you happen to know any resistance values printed on the thing?
>
> --
> Thomas Borchert (EDDH)
>

[[email protected]]

Thomas Borchert > wrote:
>karl gruber wrote:
>> Some of you wanted to see the variable resistor in the line out to
>> the temp probe.
>
> Do you happen to know any resistance values printed on the thing?

I don't know what resistance it is, but I'll add that it looks like a
multi-turn trimpot, maybe 15 turns. This lets you adjust it more
closely, and also these type of trimpots are usually sealed a little
better. This kind of trimpot is maybe US$2 at a large electronics
supplier. (The more common types of trimpot are usually less than one
full turn, maybe 300 degrees, and are usually not sealed very well.)

You could work out the appropriate resistance by measuring the
resistance of the temperature sensor at various known temperatures and
coming up with a value of "degrees per ohm". Note that the resistance/
temperature relationship of the sensor may or may not be linear.

Also, depending on the sensor, adding a series resistor probably only
lets you correct the reading (reliably) in one direction. You could
add a parallel resistor but I don't think this would work very well,
depending on the range of temperatures you want to measure.

Disclaimer: This is based on experience with electronics in ground
applications. I don't have an A&P; I don't even have a TG&Y. Your
mileage may vary.

Matt Roberds