their are several replacement kinds such as...
http://www.ksavionics.com/products/9...cht_probes.asp
As skyking says.. its only a couple of wires...
and a metal clamp.... well not exactly... because its not the wires that go bad most of the time...
If you look at the schematic you will see that both wires are held above ground... why because of the small voltage and types of metals...
yep their are several kinds of different ones and they all are not the same...
the older ones if you look at the wires coming out of them and the cable going to the inst on the dash.. you will see that they are colored... the older ones are the red/brown while the newer ones are yellow red... you can tell by the cableing as the yellow... is the newer while the brown is the older...
What is the difference... well neither will work on the other... so if you have the older system... you can't put the new probe on it... it won't work right.. neither will the cable .. nor the gauge... they all have to be the same thing... either brown/red.. or red/yellow...
Well the new ones are Yellow/Red, (called the K system) is made with Chromel/Alumel (say that 50 times and you win a chance at larrys duck if done correctly) wire... in that they have that type of wire all the way to the meter... and it has to be insulated and shelded from RF ....
the old ones are Brown/red, (Called the E system) and are made with chromel and constantan wires... all the way to the meter movement...
Which one is Positive and which one is negative...
well that was your first clue that they generate a voltage that is DC.... along with a pretty good current... In these cases the red is always the negiative (-) while the other color is always (+).
they changed from the older system some time ago because the older ones put out too much voltage... yep when you went thru the range... it would be too great for the meter movement.. to read correctly... (by the way.. EGT meters are not calibrated to a linear range... clue no. 2) so if you are parking that needle on one spot.. you are not at the same heat each time.. because as temp changes.. so does the resistance and voltage that it can generate...
But, one thing that we need to cover here... most of the time when you take the probe out of the engine... and put it in the propane torch... it reads good.. and deflects the meter movement... but, when you put it back in... ahhh well.. it just doesn't work... why.. because the forgot to tell you that the two wires are shelded from ground.. by a cermanic tube... and if it gets cracked and breaks.. due to vibration (and what skymaster doesn't vibrate).. you will short out the wires to ground... ground shorting is bad in the life of a EGT... so it will not work... be very careful when you move one around that you do not drop or damage it by shocking it...
Can you get the older ones.. yep they will make them up for you... but, you can not put a new one in... why because the new ones are about half the voltage.. but, last twice as long... so subing one is not what you want to do either... no meter movement... kinda thing...
To change the system out.. you have to replace the meter movement, cable and probes... they take no power from the plane.. and work on their own by generating voltage when they get heated by the engine exhaust...
Are their others.. yes.. their are a couple of others out their that use some different kinds of metals.. but, Alcor is the leader and founder of the EGT... why would you want to change... smile
NOTE:.... Also you don't want to hook your flashlight battery up to the system either.. as it will burn out the meter movement.. they are very... very.. sensitive and even using a DMM or VOM can damage one... to the point that it is history...
YOu can go to Alcors' page and see the trouble shooting guide if you don't have one they will send you one or allow you to download it off their web page... at...
http://www.alcorinc.com/DOCS/1/trouble.html
and while they are a good company they will not replace whiner...parts because they are bad or out of date... after all they have to make a living too... and how often do you need one... Hmmmmm.... they are like lightbulbs.. as to their life... but, most seem to go for 10 years.. or so... if taken care of... most of the ones we replace are the ones that some duck got in their and pulled the wires off of... breaking them when they were cleaning the engine... or working on it... smile...
Hope that this helps.. GMAs