[Boatanchors] [Boat anchors] JOHNSON RANGER

[Jbrannig at verizon.net]

Add to all of Bill's comments below:

Replace ALL electrolytic capacitors.
I replaced MOST of the interstage and bypass capacitors.
Check all the resistors and replace those out of spec.
Replace ALL the metering resistors.

I had an issue with VFO stability/frequency calibration,
this was traced to leaky mica capacitors in the VFO compartment.
They were all replaced.

It is a bit of a chore to disassemble the Ranger, so it is worthwhile to 
spend the time upgrading the Radio.

My upgraded Ranger has been running for several years.

Jim

-----Original Message----- 
From: Bill and Liz
Sent: Sunday, February 23, 2014 4:52 PM
To: boatanchors at mailman.qth.net
Subject: [Boatanchors] JOHNSON RANGER

Three years ago I did a number of mods to my Ranger, many of them as
described by Phil Salas, AD5X and some as suggested by WA1HLR.  Yes, with
solid-state rectifiers the B+ voltages are somewhat higher, but not to the
point where they cause problems.  My HI B+ runs around 695V and the LO
around 335, both unloaded.  I did not place a resistor in the low B+ feed to
drop the voltage but I did change a couple of screen resistors to compensate
for the higher voltage.

At full output the B+ values are 640 and 290.  This has resulted in higher
power output if I want it; I now have an easy 48-50 watts out at around 110
ma and the transformer runs a lot cooler.

I also did some VFO mods which make it settle down much faster.  Moving the
dropping resistor outside the cage and changing its value experimentally
with a variable resistor did the trick.  Tube change to a 6AH6 is very
desireable....I have done this in a few 6AU6 VFOs with great results.

I also changed from 1614 modulator tubes to 6550s as the latter handle the
higher B+ much more safely.  Apart from the greater voltage headroom there
is no difference in modulation, except now there is more of it available.

Other changes: antenna changeover jack and power supply for an external 6V
Dow Key relay, a phono jack from the PTT line to control a linear and, of
course, a 3-wire U-ground line cord and chassis-mounted fuse holder for
safety.  You might also want to add an X-Y cap across the AC input.

On-air reports have been very good and my Ranger is a much better performer
than when it was first built. Heat inside a radio is a great killer-ask all
those who have blown the power transformer in their Rangers!

Bill VE3NH


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