Neutron Build confusion

[Giglawyer]

A while back I bought a Neutron PCB for a build.  Now that life has slowed down a little for me, I am going to give it a shot. I have one question before I begin (I am sure I will have LOTS more). 

There is a resistor labeled "Rx" in the plans.  The notes say this:  "This resistor adjusts the amount of drive current to suit the sensitivity of the specific LED; it must be adapted for the one you use. Start with about 560 ohms and work up until you get a value that makes your unit have about the right amount of sweep. This should be less than 4.7K." 

What?

I am planning to use two VTL5C3s for the optoisolator option.  I have tried to search on this, and I have seen various results.  Some people suggest using a pot for the Rx.  My plan was to install a socket and try different resistors. 

Any thoughts here?  Anyone Build a Neutron with the VTL5C3s?  If so, how did you resolve the "Rx" issue? 

Thanks!

[Mark Hammer]

The sensible thing to do is to build it, sub a pot/trimpot for RX temporarily, adjust to acceptable functionality, read the value of the pot setting, and use THAT value of fixed resistor for Rx.  It is quite possible that the final Rx value may be something a little off the beaten track, but I'm sure that some combination of 1% resistor values will nail it.

[jgmorr2]

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