[time-nuts] 3.0GHz Channel 3 installation in Agilent 53132A counter
Randy D. Hunt
randy_hunt960 at yahoo.com
Wed Mar 19 13:47:20 EDT 2014
On 3/19/2014 8:26 AM, James Robbins wrote:
> Thanks for everyone's help here. I have done some further sleuthing.
> I have a second 53132A which has a 3.0GHz Channel 3. So, I switched the new channel 3 board into the old 53132A and it reads properly. Then, I switched the old 3.0GHz Channel 3 board into the new 53132A and it also read four times (4x) the input frequency. From this I conclude that the issue is with the new 53132A counter box and not the channel 3 board.
> Then I powered up each counter and measured at the pins on the ribbon cable connector at the Channel 3 board to the main board on both the new and old counters (channel 3 boards plugged in and powered). They each read the same voltages and/or grounds (pin1 = 2v; 2,5,7,9,10 = ground; 3,8 = +12v; 4 = -12v with numbering based on "1" shown on channel board).
> Someone suggested that maybe the new main board had been set up for the 12.5 or 6GHz channel 3 but was sold without that channel. The idea was that such a main board would cause a 4x reading. To my mind this is opposite to what I would think in that the division ratio for 12.5 or 6GHz would be higher than the ratio for the 3.0GHz board and would result in a fraction of the frequency rather than 4x frequency.
> Of course, it could be a FW mod (rather than a HW mod) which has been applied also.
> Any other thoughts are much appreciated.
> Jim Robbins
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Jim, I think the problem is with the Ch3 board as the issue migrates to
the other counter with the board. Also the know good board works
properly with the first counter that has issues with that board. I
don't think that it would be a firmware issue as the board from the
working counter works properly in the other counter with the non-working
board. Hope this helps
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