[R-390] Question about R-390 Calibration Osc

[Grant Youngman]

> For the multi-vibrator to work correctly, it needs to be a bit *low*  
> in frequency. It sounds like yours is simply running a bit to high.

I've done some measurements on the thing. When the radio is cold, and the
multi is apparently NOT syned, it runs at about 85 Khz, which is below the
trigger frequency.  As the radio warms up, this oscillation rate remains
very stable. After about 30-40 minutes it goes berzerk (indistinct raspy
signal as heard in the receiver and unstable trigger on the scope) and then
restablizes at a clean 100 Khz over about a 2 minute period.  At that point
it stays put, at least as long as I've been monitoring.

I set the sync adjustment when the radio was hot, which is most likely why
it pops back into sync when the radio gets hot enough.  I suppose one part
at a time tested with a heat gun is the next step.

Anyone out there have a surplus cal module for the R-390?

Grant/NQ5T