[Johnson] Ranger Tx Working - At Last

[Jim]

Hello Mike,
Congratulations on getting the Ranger to work!!!!

Hate to rain on the parade, but take a look at what Phil Salas has done with 
the Ranger
http://www.ad5x.com/images/Articles/Ranger%20Mods%20RevB.pdf  and
http://www.ad5x.com/images/Articles/FrontPanelRemoval.pdf

After a lot of looking and head scratching I followed Phil's advise and the 
results have been worthwhile.

Jim

> First of all thanks to the many folks who sent me advice, the Ranger is
> finally working "OK", I'm not 100% satisfied, signal reports are good both
> phone and CW.
>
> Problem #1 - the large slider resistor (R35?) had been replaced with one
> that was physically bigger than the original having two results, it wasn't
> secured to anything so its terminals could come into contact with the
> chassis and the drive pot had been replaced with a physically tiny one to
> accommodate it.  I suppose that in conjunction other problems or maybe
> working on the bench a nasty surprise could have happened, fortunately 
> both
> these conditions were easily visible and correctable.  Problem #2 was
> brittle and cracked insulation on the HV choke and transformer leads, this
> caused a short to ground inside the HV choke end bell which resulted in 
> the
> HV rectifier tube plates glowing red very shortly after the Tx was 
> switched
> on.  Apparently brittle insulation on the leads is a common Ranger problem
> and the usual fix is to put heat shrink tubing over the leads.  With this 
> Tx
> moving the leads even slightly resulted in the insulation breaking and
> falling off, so the choke and transformer were taken out of the chassis (A
> big job) then the end bells removed from the choke and transformer.  The
> leads were clipped close to where they entered the windings, new leads
> installed, (Correct colors) then heat shrink tubing put over the
> connections.  It was possible to shove the heat shrink down into the
> windings slightly.  Longer leads were put on the HV choke so that it was 
> no
> longer necessary to connect to the terminal strip, they went straight
> through to the rectifier socket.  Problem #3 was that many of the .005 
> caps
> had been replaced using a variety of values, these were removed and 
> replaced
> with .005's @ 1KV, in most cases by clipping the cap leads close to the 
> cap,
> bending the short wires into a hook shape so the new cap could be
> mechanically fastened to the hooks, then soldered.  The "hot" end of the
> modulation transformer feedback winding had been moved to ground, (Result
> was that both ends of the feedback winding were grounded) after moving the
> "hot" end to the correct place problem #4 occurred - strong oscillation as
> soon as "PHONE" was selected.  This could occur in a DX-100 if the plate
> leads to the modulator tubes were reversed, sure enough they were in the
> Ranger, easy fix, move the leads where they should be, result was no more
> oscillation.  Problem #5 - the parallel triple 33K resistors connected to
> the clamp tube socket (effectively 11K) had been replaced with one huge 
> 16K
> resistor, the type that bolts onto a chassis for heat sinking, and of 
> course
> it was dangling loose on the connecting wires.   Why 16K?  My assumption 
> was
> that it was the resistor on hand so it was removed and one 11K 5 watt
> resistor installed.  Problem #6 - several connections to the function 
> switch
> were not even close to what the Construction Manual indicated they should
> be.  At first I thought there might be burned contacts on the switch and a
> previous owner had made the necessary changes, but this wasn't the case, 
> the
> switch contacts were fine.  The various wires were put back where the 
> manual
> indicated they should be.
>
>
>
> Voluntary Changes.  As acquired the Tx had a press-to-talk mod that was 
> done
> according to the instructions in the Operating Manual, but this meant 
> there
> was about 110 volts on the mic switch - maybe not good with my homebrew 
> push
> button mic switch, plus the voltage divider configuration to get the 110
> volts must have produced a lot of heat under the chassis.  The old relay,
> power divider resistors and associated wiring was removed and a 12 volt 
> 4PDT
> relay installed.  A small voltage doubler circuit using dial light power 
> was
> used to power the relay via a 33 ohm resistor.  With a the 3rd set of 
> relay
> contacts it was possible to wire the red transmit light so that operating
> PHONE the light only comes on when the press-to-talk is depressed.
> (Continuously lit when "CW" is selected - the 4th set of contacts were not
> used)  The modulator tubes were swapped from 6L6's to 6L6GC's. (No 1614's
> available yet)  I almost forgot, R3 the resistor inside the VFO 
> compartment
> that reportedly overheats was replaced with a 5 watter, although there 
> were
> no signs of overheating and the resistance measured normal.
>
>
>
> Future Possibilities.  I really don't like making changes too far away 
> from
> the stock configuration but...  does anyone know if biasing the 6146 grid
> has been tried?
>
>
>
> Mike VE7MMH
>
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