Thanks Jim, I appreciate the link.
I also found some 82ohm 2W 5% flameproof resistors on ebay.
Some more goggling found that this Rochester probe w/82ohm resistor "work
around" has been used by owners of Pipers, Bonanzas and Commanders, all with
the AC Spark Plug CHT gauge. The 82ohms is the one constant in everything
I've read, the W varied between 2 and 3Watts and the tolerance was either 2
or 5%.

Not having a background in electronics, what ultimate difference would a
resistor of higher wattage rating have on the circuit, the gauge, or the
probe? If the circuit is only drawing mA's, 1) are there "smaller" mA rated
82ohm resistors available or 2) with a mA rated resistor would the required
ohm rating change? Forgive my ignorance regarding resistors, I basically
understand what they do, but do not know the implications of the
sizes/capacities. I'm just looking for a way to get out of several hours of
tedious PITA work with my upper torso stuffed up underneath our panel.

Instrument Tech of Dallas TX seems to have quite a bit of experience with
the combo and emailed me the American Bonanza Society newsletter that
contains the article. The original question was published June 1990, and
the explanation and work around was published some time shortly after
however I do not have that date.

Jim


"RST Engineering" wrote in message
...
BTW, that 82 ohm power resistor (??) you need is available at
www.mouser.com
5 watt cement coated fireproof resistors (280 CR5 series) are 39 cents in
onesies. 3 watt flame retardant resistors (283 series) are also 39 cents
in
onesies.

Mouser has no minimum order and a decent shipping policy.

Somebody needs to measure the current that these things are sucking. In
order to dissipate 1 watt in an 82 ohm resistor, you need a bit more than
100 mA (0.1 amps) to flow. My gut says that this is not happening.

Jim



"Jim Burns" wrote in message
...
But I think the width of the needle of our gauge will compensate for
that.
It's an old style gauge with only a dot at 200F and the next dot is at
400F.
The best we can do is try to keep the needle below the 400F dot a tad.
I
guess we could also calibrate it with a pan of oil, a hot plate, and a
candy
thermometer.