[Premium-Rx] WJ 8618B(S 1) A5A2 question.

[Scott Schappert]

Hello to the list !

 

I have a few questions about the A5A2 frequency synthesizer interface PCBA
inside the 8618B(S 1) receiver.  First, the manual indicates two part
numbers for the A5A2, 796321-1 (SM REV enabled) and -2 (not enabled).  My
receiver has a 794110 PCBA installed.  I have made a basic comparison of the
two different configurations, and have found that the 794110 PCBA closely
mimics the 796321-1 configuration.  Other differences are two so far: U16
U17 are CD4503 tri-state hex inverter: pin for pin replaceable with the
80C97 (called out 796321-1) and second U23 changes from CD40106 to the
74C14.  I have suspected that a worsening problem of the receiver going into
different tuning ranges (spectrum monitor), without re-setting any values on
the front panel or changing dip switch settings on A5A2, may have been
attributable to this particular PCBA installed.

 

I do not have documentation for any other 8618A receivers, or specifically
any receivers of the "B" flavour except the (S 1) model.

 

Can anyone shed some light on the origin of the A5A2 794110 PCBA, and if it
is compatible with the (S 1) receiver configuration. 

 

Finally, The PLS100N FPLA (Floating Point Logic Array) device on the A5A2
(U12); I suspect that this device is receiver serial number specific.  What
would the indications be of this device coming from another receiver ?  How
might the indication of a corrupt FPLA unveil itself ?  How sensitive is
FPLA data from receiver to receiver.  There is no label on the Signetics
device, indicating a date OR s/n.  I would expect to see a label if the
receiver specific suspicion was correct. 

 

I have been using the receiver to program IEEE488 routines, and am
encountering increased genuflection issues with this receiver. 

 

I wish to thank in advance anyone who might shed some light on this
interesting (if not tedious) situation !

 

Kindest regards to all, and the wish of good health !

 

-Scott

 

 

 

 

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