The Mysterious Predicta Network

[Crist Rigott]

I've evaluated and designed about 31 different "flavors" of the networks used in the Predicta and Seventeener line of TV's. I have good info and design data for all of them except one. The Vertical Feedback 30-6509-2 and -2A.

The data I'm using is for chassis 8H25 (Seventeener II), 8L35, 9H25 (Seventeener III), 9L37 (Holiday and Pedestal), and 9L38 (Tandem). I have all the Riders stuff for the above chassis and Sams for the 8H25, 9L37, and 9L38.

Between both Riders and Sams there seems to be no consensus as to which part number, 30-6509-2 or -2A is used on which chassis. All of the Riders schematics show the same 30-6509-2 part number but on the 9H25 schematic, the 150K resistor is replaced by a 47K resistor.

The Sams parts list for the Tandem lists a 30-6509-2A. The Sams for the Holiday and Seventeener II lists a 30-6509-2. Sams lists the same value components for both the 30-6509-2 and 30-6509-2A!

I pulled a 30-6509-2A from a 9H25 (Seventeener III) and ohmed it out between pins 3 & 4 and got 160K. There should be a 47K between those pins according to the schematic in Riders. Also I checked the other 33K resistor and got 35.7K.

I also have a 30-6509-2 from a 8H25 (Seventeener II) and ohmed it out too. Between pins 3 & 4 I got 171K where a 150K resistor is according to the schematic in Riders. Again I checked the 33K resistor and got 39.2K.

So from what I have on hand in actual networks, even though they have different part numbers, they ohm out pretty close to being the same.

But wait, there's more!

Bob Andersen has made many videos and pictures of his restorations of most of the models (chassis) of Predictas.

In his picture album "Predicta Holiday II Chassis", picture titled "More Replica Networks", it clearly shows a 30-6509-2A and he used a 150K resistor. Now Riders and Sams both says that chassis should use a 30-6509-2.

In his picture album on the Tandem II restoration, picture titled "Replica Networks" , he shows a 30-6509-2A (which agrees with Sams) and used a 150K resistor.

My buddy sent me some pictures of a Tandem (9L38) and it uses 30-6509-2A. Again this agrees with Sams and what Bob had in his Tandem chassis.

All very confusing when trying to figure out what really goes where and most important, what value resistor goes with each flavor of the 30-6509-X(X) network.

It seems that most of the schematics use the 150K resistor with the 30-6509-2 part number. The only different schematic, that I have, uses a 47K resistor but is still listed as 30-6509-2 on the schematic.

Does anybody have any information on this network and its flavors to help me sort all of this out? It would be appreciated.

BTW, I hold Bob Andersen in high regard and in no way are the above references to his albums to be construed as a criticism in any way.