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HP 8560E spectrum analyzer YIG YTO A11 question/problem

Question asked by 4thdoctorwhofan@gmail.com on Apr 8, 2016
Latest reply on Nov 28, 2018 by dhamilton
I have a 8560E which does not display any signal that is applied to the main input.  After initial boot there are six error messages.  After some troubleshooting, I think the problem is with the YTO A11 assembly but since I'm not that familiar with repairing this type of equipment, I thought perhaps some help is in order.  The assembly for the YTO in my unit is 5086-7906.  I guess there are probably no schematics available for the YIG right?

Since I am not measuring any signal directly out of the YTO, I thought perhaps something is wrong with the drive to it instead of a faulty YIG.  The drive comes from connector J3 on the A14 board.  Below is what I am getting on the J3 connector:

Pin 1:  -14.98V (-15V supply voltage)
pin 4:  4.61V (with the connector removed I get 4.96V, not sure if this is a problem;+5V supply)
pin 5:  -3.3V (main coil +)
pin 6:  -14.98V (main coil -)
pin 8:  14.75V (with the connector removed I get 14.88V, not sure if this is a problem;+15V supply)
pin 9:  voltage fluctuates between .5V & 2V (FM- signal)(I read 15mV with the connector removed)
pin 10:  voltage fluctuates between .5V & 2V (FM+ signal) (I read 13.6V with the connector removed)

Does any of this seem normal or is something way off base?  I'm just not sure what "normal" readings would be on the connector.  The attached file is the connector in question.

Any advice or help would really be appreciated.
Thanks!
Tony

Edited by: 4thDoctorWhoFan on Apr 8, 2016 8:01 PM  

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