[Lafayette] He-80 / JR-60 crystal calibrator

[Ken\Marlene]

Hi guys

 I've just about finished restoring a TRIO JR-60 (Lafayette HE-80) and it's
working splendidly except for the crystal calibrator (advice: replace all
the electrolytic caps, the RF gain control, and whatever tubes are
necessary. Then do a good re-alignment).

 I've tried two 100 Kc junkbox crystals (specs unknown) and they both
oscillate slightly high in frequency even with the calibrator trimmer cap
(20-60 mmfd) at maximum capacitance (tight!). One is close enough to WWV at
10 Mc that you can hear the beat, so it must be within a couple of Kc, but
that's as close as it will go.

 Does anyone know the specifications for the optional 100 Kc crystal? From
the schematic, it appears to be parallel resonant, but the load capacitance
isn't stated. My best guesstimate is about 40 mmfd (that's 40 pF to you
youngsters) which is higher than the usual 32 mmfd that rocks used to be cut
for and would explain why I can't bring it to zero beat.

 Also, what's the normal AF response like for one of these radios? Mine has
no high-frequency (treble) response. I  guess that's considered
'communications' quality.

 Thanks for whatever help can be offered. If I can be of  help, just ask.
73.


Ken, VE3FIT