Greetings,
Having experienced a repeated condition of unlock in spite of all DC levelsfrom the Rb Phase Lock circuitry being correct, I traced the problem to A14,the logic ass:y. I went about to replace almost all discrete transistorsthere after testing and discovering that some of them was leaky.No problems after that except that I did not find an easy wayto replace CR13, a 3N58 according to the parts list.
Any modern readily available type that will do?
All the best
Ulf KylenfallSM6GXV

The CR13 can be almost any small SCR, like in a TO-92 size. I happen to
know of one offhand, because I just yesterday used it in the Z3801A
project, for the same type of function - latching the state of the
indicator. I have a bunch of these in the thyristor department, and
looked up various ones until I found this particular part was about right.

https://datasheetspdf.com/pdf-file/284595/UnisonicTechnologies/XL1225/1

This is an oldie. Another classic one is the C103 SCR. There should be
plenty of modern little SCRs that will do. If nothing seems right, you
can always make your own equivalent from a PNP and NPN Q tacked together
right - but two parts are needed, and possibly an extra resistor or two,
so it would be kind of a kludge.

For an SCR, the main things are gate current sensitivity, trip
(latching) anode current, and holding current.

BTW in my Z3801A project, the SCR holds the "power on" state, but I
drive the lamp the opposite way. It stays off in normal operation, and
lights amber to warn that AC power has dropped out in the past - simply
because I have plenty of a certain style amber lamps, but only one green
(for lock). The reset button trips the SCR back on, and the light goes out.

I found the circuit wouldn't latch at first - I had made the anode
current only about 1 mA, well above the holding current, but the trick
is you need the available trip current to be high enough to go, then it
holds down to much lower amounts. Changing to a smaller resistor made it
work.

Ed

You might try a 2N5060 scr.Sent from my Verizon, Samsung Galaxy smartphone by Morse code.
-------- Original message --------From: ed breya eb@telight.com Date: 10/10/21  3:36 PM  (GMT-08:00) To: time-nuts@lists.febo.com Subject: [time-nuts] Re: 5065A - Replacement of A14CR13 (Logic Ass:y) Thyristor "Continuous Operation" ? The CR13 can be almost any small SCR, like in a TO-92 size. I happen to know of one offhand, because I just yesterday used it in the Z3801A project, for the same type of function - latching the state of the indicator. I have a bunch of these in the thyristor department, and looked up various ones until I found this particular part was about right.https://datasheetspdf.com/pdf-file/284595/UnisonicTechnologies/XL1225/1This is an oldie. Another classic one is the C103 SCR. There should be plenty of modern little SCRs that will do. If nothing seems right, you can always make your own equivalent from a PNP and NPN Q tacked together right - but two parts are needed, and possibly an extra resistor or two, so it would be kind of a kludge.For an SCR, the main things are gate current sensitivity, trip (latching) anode current, and holding current.BTW in my Z3801A project, the SCR holds the "power on" state, but I drive the lamp the opposite way. It stays off in normal operation, and lights amber to warn that AC power has dropped out in the past - simply because I have plenty of a certain style amber lamps, but only one green (for lock). The reset button trips the SCR back on, and the light goes out.I found the circuit wouldn't latch at first - I had made the anode current only about 1 mA, well above the holding current, but the trick is you need the available trip current to be high enough to go, then it holds down to much lower amounts. Changing to a smaller resistor made it work.Ed_______________________________________________time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.comTo unsubscribe, go to and follow the instructions there.

Rick wrote:

"I just wanted to clarify that crystals are quite capable of
jumping without any help from temperature shifts.  The E1938A
proved this.  With a thermal gain in the hundreds of thousands,
the crystal temperature never budged.  Yet the crystals (which
were essentially the same as what was in the 10811) did jump;
every one of them from time to time.  There were no crystals
that "never" jumped, depending on how you define "jump".
A crystal might appear not to jump for while, but if observed
long enough you would always see a jump sooner or later.
It wasn't like you could sort them for "non-jumping" units.

The situation reminded me of the so called "smart clock"
concept, where the clock would "learn" what its aging was
and then compensate it out during hold over.  The trouble
with this was that the aging curves have "knees" in them
and you are hoping that a knee doesn't occur during holdover.

With the advent of small, low power, affordable atomic frequency
sources, we now have a way to get rid of jumps."

But don't all these atomic frequency sources ultimately (in practice)
depend on crystal oscillators anyway, making them subject to the same
jump issues?

Ed

Since the measurements indicate pass-through with no frequency effect,
you have to look at amplitude. Check to see if there are any diodes
across it, like a limiter PIN or SRD. A curve tracer would be best -
check both polarities, of course.

Ed