[Findm-Keepm]

My sincerest apologies - the tuner in these doesn't have the griplets either. The white wires you see? Jumpers that solved the problem in the 112 and 130 channel tuners. (EP93X442 and EP93X590) - the earlier 108 channel ones did - they were used in the AB/AC remote/random access sets.

The BC-A chassis tuners used a Siemens design, straight from their datasheets, minus changes made for North American use. Grundig also used the same design/chipset for the prescaler and band-switching chips.

108 Channel tuners used a Toshiba or NEC chip set that was rock solid. Some folks modified them for use as tracking generators for their homebuilt spectrum analyzers. The local oscillator in the tuner was shifted, filtered and tapped for use.

One of these days, when I get a new all-in-one printer (my Canon Pixma died...) I'll scan all of the GE Engineering notes found with all of the Engineering Dept stuff. Some of it is boring - small value changes in resistors, caps and the like for performance improvement over the datasheet designs, and outright breakdowns of competitors stuff, like Sony tuners, RCA (pre-GE) tuner control modules. Other stuff is insightful - like what CRT brands and types had the best resolution with their chassis (EC and AB/AC only, nothing later...).

I think I've posted pix of bare PC-A chassis boards I have where they were checking out temperature effects on different Phenolic materials used in the boards. I've also got modules with no markings on the board, extra holes, and "ENG SAMPLE" stamped in ink on the boards. I thinned them out some - and salvaged CRT sockets, power resistors and hardware, keeping only the best 4 or 5 boards - some date back to the JA/MA/MB sets of the 70s.