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ocxo/synth 2014 & U3S Rev2 2014 with v3.08 chip #u3s #ocxo #pcbversion #building


Graham J Smith G4NMD
 

After various health mishaps and house moves now getting round to building.

I need to clarify a confusion.  on page 37 of the ocxo build manual step 82 it talks about removing pin 12 if using with ultimate 3 .... then in bold type at bottom of step it says does not need to be removed for U3S or other applications..... step 88 shows pin removed and step 89 testing with U3S.

If I am to build and use this module with my yet to be built 2014 U3S Rev2 board ... do I remove pin 12 in step 82 or not?

Hopefully the group can advise (on the grounds the daft question is the one you do not ask and then make the error!!)?

Graham
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Graham J Smith
G4NMD
N4GJS


Mike Berg
 

I believe the pin was removed to be compatible with the old 9850 type oscillator.

The new Si5351a synth board has pin 12 grounded and your U3S pin 12 should be as well.
Mike

 


Graham J Smith G4NMD
 

so by new boards do you mean not the 2014 Rev2 board I have?
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Graham J Smith
G4NMD
N4GJS


Mike Berg
 

I'm of the understanding that the U3S was the major revision that switched VCO types, but that was before my time here.

To be absolutely safe, remove pin 12.  The Si5351a has plenty of other grounds.