Johnson Viking

[Don, W2DL]

Hello all,
A friend of mine just called and said his Viking all of a sudden lost all audio, tubes are lit, RF output is normal. As I remember this rig uses a driver transformer to go from single plate to P-P grids, and I also somehow remember the driver xfmr does have a habit of developing an open winding. Question is, if it does turn out to be the driver xfmr would a Stancor A53C work? This is rated 10k single plate to 90k p-p grids, or 1:3 ratio. I don't know if the grids in the Viking pull any grid current under modulation, if so the rig might need a more normal Class B driver xfmr which can drive the grids into the proper region.  Any ideas ? I do have a Stancor A53C, that's why I mention it. A proper class B driver xfmr would be a lot harder to locate, I'm afraid.

73
Don, W2DL

[ka3zlr]

Good Morning Don,

 On the two Viking II's that i have restored, I replaced the driver transformers with Hammond 124B series here's a link if you want to look at the specs:

http://www.hammondmfg.com/124.htm

It's a nice little tranny fits well in the stock position and it has some nice criteria.

73
Jack.

 

[WA1GFZ]

Check the cap feeding the audio level pot. The past two I did had a leaky cap saturating the audio driver tube.

[N3DRB The Derb]

zlr has the good dope. I used 2 of those trannys in 2 of my viking 2's over the years. The stock one is a joke, as is the entire stock low level viking 1/2 audio system.

the "universal" hammond driver transformers from antique electronic supply is also a good choice.

http://www.tubesandmore.com

[WA1GFZ]

I had an A53 in one of my V2s. it is a bit larger than the stock one.
I changed the driver to a 6AQ5. It worked AB1.