[Bill Hutchinson]

Here's the SS circuit I used for replacing a synchronous vibrator pack I described in another part of the Phorum. Pardon my hand drawn schematic.

[Image: http://i27.photobucket.com/albums/c170/p...brator.jpg]

A couple of notes - all resistors are 1/4W unless otherwise specified. The view of the socket is from the bottom (pin) side. I used a junked 6 pin tube for the connection. The use of D3 and D4 provide rectification across the transformer's secondary, and I incorporated it into the circuit, so as to create a 1:1 replacement of the original pack.

The original circuit was designed to run from 12V, but didn't provide enough voltage (about 100V DC under load) when using a 6V supply, so I changed R3 and R4 from 150 ohms to 75 ohms to create more base current on the transistors, and the end result was 170V.

The transistors were mounted on a sheet of aluminum, a spare Radio Shack project box cover, and I used an RS PC board to mount the remaining components, then seperated the two using PC standoffs.

I built this into a Zenith 6V27 farm radio, but I'm sure there are plenty of similar Philco radios that would benefit from replacing the vibrator pack with a SS unit.

Hope you enoy the circuit. Many thanks to Norm Leal for his assistance in this project.

Bill