[time-nuts] HP 1820-0313 4.2V Logic (Flip-flop)

Ulf Kylenfall ulf_r_k at yahoo.com
Tue May 16 16:33:43 EDT 2017

Starting to trouble-shoot some of the 5065A circuitryI saw that the (mechanical) clock drive flipflop IC1of the digital divider ass:y A16 is behaving very strange.
All of the voltage regulator circuitry in this ass:y is working,providing 4.2V and so on, but IC1 and the two transistorsQ11 and Q12 exhibits a strange behavior.
When IC1 is driven by a 1PPS squarewave of 0...4.2Vthe outputs of the transistors goes from either 0...4.2VOR 4.2...13V OR 0...13V in a random pattern.I can see this also at the bases of the transistors.The 13.3V is stable
That the 1820-0313 is unobtanium I can understand.Has anyone created an equvalent based on discretesor is there a suitable SMD "single" flip-flop like single gatesthat could be suitable?
(Just want to know if I should scrap the Option 01 and 03alltogether)

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