[time-nuts] FRK-L Rubidium

Tom Curlee tcurlee at sbcglobal.net
Sat Feb 9 14:53:35 EST 2013


I'll add my own FRK-L failure story.  I have a FRK that suddenly stopped locking.  The 10 MHz was there, but off frequency so much that I couldn't adjust it to sweep over 10 MHz.  It suddenly occurred to me that the crystal oven housing should be hotter than just barely warm to the touch (it's usually too hot to touch).  I found that the Darlington transistor that is used as a oven heater was bad.  Replacing the transistor fixed the problem.

Tom

--- On Sat, 2/9/13, Dan Rae <danrae at verizon.net> wrote:

From: Dan Rae <danrae at verizon.net>
Subject: Re: [time-nuts] FRK-L Rubidium
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Date: Saturday, February 9, 2013, 10:31 AM

Since we're offering up faults for the FRK, I'll add one that I've found: there's a CMOS 4060 oscillator that should go off at 8.128 kHz, set by an adjust on test R.  If this drifts off enough the lock will never happen.  It provides the FM frequency for the synth.

Dan
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