[Boatanchors] Johnson Matchbox 275W

[telegrapher at q.com]

In hooking my 275W matchbox to the Viking II and back to the R-388 i'll be using with it i noticed that i could not get any signal thru it in the receive direction.  Well one thing is that the receive side is 300 ohm out to the receiver.  Hmmmm, a TV 300/75 ohm balun fixed that.  Still no signal.  Why does it have the extra coax connector on the back side.  What was it put there for?  Better pull it apart and see what is going on.  True to Johnson products, there are somehwer close to 10, 000 screws in it.  Well not really but if you've taken the bottom off the Viking II, and i suppose the Viking 1 is similar you know how to remove lots of screws.   Back to the topic at hand.  When i finally got the cover off the problem became pretty apparent.  On the screw terminals for the antenna lead to the receiver, nothing was attached to the supposed hot side.  The coax connector that was added, apparently part of a mod goes to the common leaf on one side of a 3 pole relay.  Both contacts whether operated or released runs the center contact of the coax connector to ground.  Wonder what was accomplished there?  The RF input connector which goes to another side of the relay was totally bypassed so the tuner was in the line all the time and could not be switched out.  Simple jumper removal and addition here will fix this.

Why or what was the purpose of the mod to add the coax connector and were there other changes included?  I've got the documentation off of Edebris or the Bama site but there is no mention of any mods.  I think i've heard from other sources that the 275W matchbox did have a coax mod done to it and i think it is for the receiver side but not sure.  Any clues from other users that have one of these?  Otherwise it appears to be a very nice clean unit.

Larry
W0OGH