Thanks.? I've been working off of the 8753B CLIP, not too much has seemed to have changed.? What is the part number for A11 in the 8753D?? In my ES it is 08753-60162.
What I'm seeing is that the YTO is over 200 MHz too high on the lower frequencies (under say 1-1.5 GHz) so the test 48, generate proper pretune voltages, fails.? The output at P1-1 to P1-2 is somewhat higher at the low end than the manual shows, being 4.0 volts in mine vs. 3.5 volts stated in the manual.? U18-6 voltages (not shown on the schematic shown below), out of the DAC, look good.? The drive signal from A11 is current rather than voltage so a slight difference could be attributed to tolerance of my YTO coil resistance (45.2 vs. 44.4 ohms?? Not enough for that difference).? I also tried swapping the YTO for another and the replacement behaved exactly the same.
The instrument PLL locks nicely when using an external source.
Where did you find the CLIP you sent?? I'd like to see the rest of the A11 board, and maybe more, as it may be closer than the A/B CLIP I have.? And I'd *love* to see a CLIP for the A3 source PCB!
Peter
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On 3/16/2019 8:42 PM, pianovt via Groups.Io wrote:
Maybe this will be helpful. It's from the 8753D, but should be the same for the ES.
Vladan
