[Chuck Schwark]

Ok - here we go Bill.

I love the prototype AB Mystery Pack.

[Image: http://www.philcorepairbench.com/images/newpack01.jpg]

Two things to tweek:

1. Thickness dimension. Needs to "snug" into the hold down tabs on the Mystery Control:

[Image: http://www.philcorepairbench.com/images/newpack02.jpg]

[Image: http://www.philcorepairbench.com/images/newpack03.jpg]

2. The socket need firmer contacts. The formed soft brass stock bends and looses contact with the Mystery Control battery plug pins too easily. Consider using salvaged tube socket contacts? The four socket contacts need to be springy stiff, if you know what I mean.

One another note. Loaded the pack with the 2 C cells and 5 9-volts and "warmed up" my intact Mystery Control that I had not tested since I got it. It sprang to life most adaquately. Here is a scope capture of the RF output at the plate of the #30 tube being held in the "ON" mode and not pulsing. As you can see, the peak-to-peak RF output is 60-70 volts. Plenty of punch in my book. I adjusted the variable cap to move the frequency around a bit. The cap has more range than the five Philco specified 350-400 kHz Mystery Control "channels," and seems to put out a very respectable sine-wave signal with a minimum of distortion.

[Image: http://www.philcorepairbench.com/images/...%20Wfm.jpg]