Tejon frequency drop over time?

[kac]

Few months back my Tejon was running 17.5khz. Last I checked as I was comparing coils is it is now 16.2khz. What would cause it to drop?
I only see 2 pots on the board not sure if I can adjust by those or if it may be a failing component like a cap?

Any suggestions would be appreciated.
Ken

[vlaser]

Hi.
Where do you measure the frequency?
It is necessary to measure the output of comparators.

[kac]

Was using a coil sensor and scope. Sensor seeps pretty accurate as it showed my other machines as correct frequencies ie AT Pro at 15khz, Apex at 5,10, 15, 20 khz, Multi Kruzer at 5, 14, 19 khz.
I checked again against all my coils and all exactly the same. Any idea what would cause it to drop?

[vlaser]

Tesoro Tejon has an auto generator.
It is necessary to measure on comparators!

[vlaser]

Yes.

[kt315]

Was using a coil sensor and scope.

when you bring a coil, this is a copper mass, in the detector coil you get the frequency decreasing. it is normal for phisics rules.
unferrous decreses the freq. remember detectors with BFO principle working.
you must measure ON BOARD, after preamp for example
also, check around the coil - there are not be metallic objects around, nails/srews in a table,
metallic fittings in a wall/floor near, electric cables 120VAC, etc.

[kac]

I hooked my scope directly this time, there is a 2hz difference between sensor and direct scope connection which is the sensor being +2hz. Not a big difference.
Tejon read in at 16.1khz and change.
I will try to find a quiet spot in my shop to test away from everything and test again. Could be fine and I might be just paranoid.
Thanks!
Ken

[kt315]

connect another coil you have and measure again. you have to understand a cause is in the block (TX generator) or in coil.

[kac]

Was in fact objects around the coil that caused it to drop.
Pulled the machine away from benches and fired it up and frequency is correct.
Thanks so much!