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. 73, Jim Robbins N1JR _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
