[Central-Electronics] 100V 160M kit

[GRANT YOUNGMAN]

On Apr 27, 2014, at 11:55 AM, GRANT YOUNGMAN <nq5t at tx.rr.com> wrote:

> Has anyone on the list installed the 160M kit in a 100/200V?  I bought a mod kit from Nick several years ago, and never got around to installing it.  So while I had the transmitter splayed out working on some other issues, thought I’d bite the bullet and put it in.   I’ve sent a query to Nick, but haven’t had a response yet, and being generally impatient, thought someone here may have been through it.
> 
> The additions to the affected driver section plugins went smoothly and are complete, but I have a couple of questions related to the installation of the resistor/caps in the RF deck around the 160M coil socket.  I’m slow enough that the installation drawing compared to physical layout and connection points isn’t entirely clear.
> 
> Thanks … Grant NQ5T


Ok .. figured it out.  It helped to look at a 200V schematic for comparison.

This link is a partial schematic of the 200V final section.  http://www.emmittsfixitshop.com/files/Download/Projects_CE200V_schematic_set.pdf


Note that in the 200V there is already a 15 ohm 2W resistor and .01 bypass cap at the junction of the output coupler HV pin for the “X” coupler.  To add the 160 kit to the 200V it is only necessary to add a second 15 ohm resistor in parallel with the existing one (R607) , and same for the .01 bypass (C607).  None of these parts are prewired in the 100V and the HV lead connects directly to the socket as does RFC-1 and it’s bypass cap, which makes it difficult mechanically — so the issue becomes one of breaking the high voltage feed at the socket and inserting a 27 ohm resistor and a pair of .01 bypass caps at the C-607/R-607 location.  Part of the complication is that the high voltage feed to the coupler sockets is “circular” — meaning that it heads off from the switch contact in both directions and runs between the sockets in a continuous loop, connected to the switch section at both ends.   Not sure whether this HV chain can be broken at the “X” socket, which may simplify installation, or if it necessary to leave the loop in place.  Assuming it was wired this way for a reason, I’m going to try to leave it in place.  Since I don’t much like the idea of leaving a HV connection hanging in space, I may also need to add an insulated tie point in there.

I think it’s going to be a long evening :)

Grant NQ5T