[Johnson] Ranger VFO question.

[Dee C. Almquist]

Morning All
Had to make a few comments on Ranger restorations. As to the "arcing" of the
VFO sw., that is common on a lot of Rangers & can fry the 470 ohm resistor
inside the VFO can. What to do? The best approach & the one I do on every
restoration is with the Dremmel tool (w/ flex shaft addendum) & a
carborundum blade wheel, carefully grind both contacts of opposing edges on
the switch off so that the rotating contact will not "short" when rotating
from 80m to 40m. If you are not brave enuf (grin) to try that, REMEMBER to
move the crystal / VFO select to "crystal" position before changing those
bands. Problem only happens when going from 80m to 40m. No worry on other
band changes. Seems Johnson bought many VFO switches with that err problem!
How do you know you have one of those switches? One time you will get that
aroma of burned resistor as the smoke comes thru the freq adj. holes of VFO
can. And then no VFO operation @ all.

Comment on SS the power supply: I solid state most restorations. I have no
problem afterward. Reason is the HV NEVER goes over 600v (+ a little). If
one makes the mistake of placing a filter cap on the INPUT SIDE of the
filter choke, B+ will go 800v ++! Don't do that! Choke input only. By SS the
LV, voltage is typically 380v - 400v. These are no load voltages. Voltage
drops under load somewhat. I find by SS'ing, the no filament current helps
on the overall heat condition on old transformer (the lo voltage tf). Also
under load, the net 380v of lo voltage works better for my 300v SS regulator
I use to feed the modulator screens & clamper tube. I eliminate the 50w
"chassis heater" altogether & obtain my modulator idle current from off the
minus supply off the CW time delay deck (also regulated & a 10K 10 turn pot
added). However, these SS devices are "plug in " devices. So the tube socks
are factory wired. One other thing needs to be done on all Rangers: The
problem w/ arcing on switches. Almost all Rangers have hi grade function
switches. If cleaned & contacts are in good shape / adjusted properly, I
have never had a problem w/ that switch. The problem comes on the METER
SWITCH. That dude has HV on it all the time. Best solution is replacing it
w/ Centralab 2003. Yep, its costly if you have go out & buy one new from a
supplier ($35. maybe). Look for one @ hamfest. Make sure its porcelain
before putting your money down. Next best thing to do is thoroughly clean
the meter switch & then CAREFULLY paint the wafer front & back w/ HV enamel,
the kind they used to used on TV HV circuits & use in motor shops today on
electric motor rebuilding. I have never had a problem yet doing that. The
problem on that switch is where HV contacts are too near the grounded frame
of that switch. That's where special care has to be taken.

These are just a few suggestions I hope you Ranger Afectioneros might find
helpful (essential?)

Very Warm Regards
Dee, W4PNT


----- Original Message -----
From: "Jim Brannigan" <jbrannig at optonline.net>
To: "Johnson at Mailman. Qth. Net" <johnson at mailman.qth.net>
Sent: Monday, October 18, 2004 5:10 PM
Subject: [Johnson] Ranger VFO question.


> After a couple of months of on and off work, my refurbed Ranger was ready
> for a smoke test.
>
> The smoke was kept in and the preliminary VFO tests (as outlined in the
> construction manual) were passed.
>
> However, as I switched from 80 to 40M, or 20 to 40M, I noticed a large
spark
> at pin 8 of the VFO switch (inside the VFO shield)
> Has anyone run across this before?
>
> Jim
>
>
> Johnson mailing list
> Home: http://mailman.qth.net/mailman/listinfo/johnson
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:Johnson at mailman.qth.net
>