E F Johnson Question - Need parts
Rodger
WQ9E at DTNSPEED.NET
Sat Jan 27 10:13:15 EST 2007
Bruce,
Sorry I cannot help you with a spare but when you find a new transformer
carefully check the wiring from T2 to the 866 sockets. On earlier Valiants
(both kit and factory) the wiring from the transformer to the 866 cathodes
is standard hookup wire with very thin insulation which is not sufficient
for the high voltage that appears. This wire will arc to ground where it
runs near the chassis and blow fuses which is probably what was happening
when the former owner decided to add the 20 amp fuse which then turned T2
itself into a fuse (or smokebomb). If you have the standard hookup wire
replace it with wire designed to carry higher voltage. If this is what
happened, there is a small chance that T2 is okay except for the 5 volt
winding being open. If T2 is otherwise okay, you can disconnect the 5 volt
leads and use solid state replacements for the 866 rectifiers.
Unfortunately, it is usually the transformer primary that gives up.
Also, you should loosen the insulating coupler in the VFO drive before
working on the Valiant. When you turn the Valiant upside down the front
panel will try to flex and the coupler will try to resist this flexing-and
lose. I found this out the hard way the first time I worked on a Valiant.
The Valiant was my novice transmitter and I have a couple of them today.
The 18K resistor in the VFO and the 866 cathode wiring are common problem
areas. Also be aware that the meter shunts (particularly in kit built
units) may be far from correct so you should check these for accuracy while
going through the transmitter. Mouser and others have precision low value
resistors you can use for shunt replacement. If the VFO tuning is stiff
and/or does not feel smooth the ball reduction drive needs to be cleaned and
lubricated. I have had to do this on one of my Valiants, both Rangers, and
my Viking Pacemaker and I imagine my soon to arrive 500 will need this also.
It is easy to clean, just keep track of the sequence of parts as you do
disassembly. Some people have had problems with the fixed output loading
capacitors but so far this has not affected any of my Johnson transmitters.
Good luck with your repair!
73, Rodger WQ9E
> -----Original Message-----
> From: Boat Anchor Owners and Collectors List
> [mailto:BOATANCHORS at LISTSERV.TEMPE.GOV] On Behalf Of hudlerb1 at netzero.com
> Sent: Saturday, January 27, 2007 8:40 AM
> To: BOATANCHORS at LISTSERV.TEMPE.GOV
> Subject: E F Johnson Question - Need parts
>
> Hello,
> Now that I am officially a true boat anchor owner, and a member of this
> fabulous list, of
> few questions please.
> I've got a pretty nice Valiant I, but it needs repairing. Some idiot put a
> 20 amp NO BLOW
> fuse in the primary of T2 and of course it is SMOKED. I think I'll have a
> rough time
> replacing this item, what do you folks suggest?
> Is some one able to rewind the thing or just keep poking around for one
> that is being
> parted out. I think this is a common problem, so the remaining parts are
> going to be
> scarce and expensive.
> Any other alternatives, such as two or more separate transformers?
> Please help! I'd LOVE to get this thing on the air again.
> Bruce WA3MKC
>
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