[Johnson] Ranger II resto

[C E]

After my work on the Navigator, I decided to switch
off to another lingering project: a slightly modified
Ranger II. The modification was somewhat acceptable.
The chassis had been drilled to accommodate a fuse
holder. Ditto with the cabinet shell. The mod was
sanitary but now the cabinet is permanently mated to
this particular R2.

Whoever did the work on this R2 before did a bad job.
They took a chassis mounted electrolytic and wired it
though one of the 7027 sockets. Of course, I removed
the unit. Luckily, there were no other permanent mods.


I also replaced the 18k 2 watt unit and brought it out
to the bottom of the chassis via two wires soldered to
the leads of the OA2 resistor and soldered them to a
pair of 43k ohm 2 watt resistors hooked in parallel.
That's 21.5k ohms at 4 watts rating. I don't think
that would be bad. Near that resistor bank, I also
replaced the old 30 ufd l.v. filter cap with a 100 ufd
unit at 450 VDC as I had done in prior Rangers. 

I removed the 750 VDC h.v. capacitor and sustituted
two 47 uF caps (rated at 450 VDC per), hooked them in
series with two 470 kohm resistors paralleling each
cap for voltage equalization/bleeding purposes. I
built the replacement using two terminal strips on top
of the choke where the old 8 ufd cap was stationed. It
looks fairly sanitary. 

I also cleaned up a fair amount of crud that seemed to
pervated the aluminum chassis with a weak solution of
white vinegar. I followed up with wiping down the
chassis with water to neutralize any remaining vinegar
residue. 

Incidentally, I took blow-by-blow pictures of the
transmitter being dismantled from the old front panel
(which had holes in it). I hope to write up a
procedure for ER. No, I didn't want to polish the
chassis to a high sheen (as others have done) but I
did want to show a completely stock unit that was
fairly clean.

I did one screw up: I turned the transmitter chassis
on its end (which scrunched the final coil). I ended
up cracking the top plastic coil form but after
bending the coil back into shape, it looked fine.
Plastic modeling glue to repair the crack should
suffice alongside gluing an acrylic support piece at
the bottom side of the coil form.

Stay tuned for more addendums. 

Cal, N6KYR/8


 
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