Johnson Viking Valiant Meltdown

   I had acquired a Viking Valiant from a local friend who had experienced a major melt down down of the unit, he did everything right but it was just time for the transformer T-2 to go. T-2 is very busy and has two sets of fairly high voltage windings(430 volts CT and 620 volts CT) and has a 2.6,6.8, and 5.4 volt winding. Finding a replacement was going to be hard and the price of a Peter Dahl replacement may be out of the realm of this projects goals. When T-2 went it spewed oil everywhere and destroyed some of the wiring insulation as well as infecting the fine coupling variable tuning capacitor.

   Anyway I acquired the beast and proceeded to clean it up and replaced most of the wiring in the melt down area (MDA)with Teflon insulated wire. Bobby my buddy had stored the unit outside in his shed for six months to "air it out" However the sniff test by the XYL prompted additional guidance on "airing" and cleanup prior to the Viking being welcomed into the home work shop. I decided to out board two transformers in order to power up the unit and see if it was going to survive.




First step is to mount wooden supports on the rear of the chassis so that you can flip the rig over to work on it with destroying the tank circuits. The starboard*** side has a single wooden support.


*** See Glossary else where




Wooden blocks were wired to the top of the HV transformer for support on the port *** side. After the
repair is finished you can leave them on for that rustic
effect. I didn't have no baling wore*** so used aircraft safety wire to secure the block's


             * * * see Glossary



The Melt Down Area(MDA), what a mess. PCB's anybody? All PCB material was carefully removed and put into plastic double sealed air tight containers and taken by courier for delivery to the proper agency for disposal.


The fine tuning variable condenser had to be removed and complete cleaned and over hauled.



All of this damaged wiring in the starboard corner will have to be replaced.
Two variable voltage power supplies. One of my favorite tricks when testing a piece of equipment is to power up each individual power supply cap using a variable voltage power supply, this way the cap rebuilds and I don't have to fire em all up at the same time, but . . . it is more exciting to just leave the caps alone and let er rip.
The 6BY5 "wreck d fier" failed and I put in a temporary mod of diodes,funny how temporary fixes become permanent. I used Motorola control head tip pins to hold the diodes but pins removed from an octal tube will work fine.
Decoupling beads were added to the wires as they left the chassis. Don't laugh, my budget does not include a Peter Dahl replacement transformer at this time. But I got lots of beads and Teflon wire.
New high voltage caps, small aren't they?




Anytime you work with high voltages always discharge the caps and power supply with a grounding probe.




A extension was added to the tank circuit shield to give additional shielding to my added external wiringfor the outboard transformers. The shield was held in place with metallic duct tape.
I needed two transformers to arrive at the correct voltages. Note that I added barrier strips for convenience and lexan plastic covers on the transformers for safety.




                    A closer view of a transformer with barrier terminal strip and its plastic lexan cover.
Remember that the neutralizing capacitor is above ground and insulated from the chassis, here I used a home brew wooden dowel screw driver to adjust the capacitor.
   Lots of High Voltages present in this transmitter, be careful, take electronics courses, read books, keep one hand in da pocket, seek professional help including therapy






The RF tank section cleaned up nicely
The bottom is all cleaned up and ready for inspection by the Commander In Chief.



  Testing using a 200 watt light bulb as a load. You can't do this with a rice box transmitter! Note the roll around table used to keep projects handy when you have to stop work on a particular project and work on something else on the bench. Helpful if you have electronics AD. Keeps the bench clear for important stuff.

 

Dis is the goal, fully operational C U on 160 or 10 meters on double sideband AM (note) with carrier.

Note: after all folks, SSB with supressed carrier is AM!

 

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              *** See Glossary elsewhere