[Premium-Rx] Racal 9400 reference osc "jumpy"

[Stein-Olav Lund]

Hello,

I have an older VHF transceiver tester from Neuwirth which uses a Racal
9400 reference oscillator at 5 MHz.

I discovered that the built-in frequency counter was off by around 12
ppm, and as I measured the output

from the ref osc (with a calibrated Fluke 1900A) this was also off by
the same amount.

The 9400 has a hole for a trimmer tool, but as the freq sometimes seems
correct, I am reluctant to "twiddling" the adjuster.

Are these oscillators possible to open for repair without destroying
anything? Any tips are welcome.