I have a thread started here: http://antiqueradios.com/forums/viewtopic.php?f=8&t=194028 about this thing, but I'm not having much luck finding out what is contained in the "mod unit". Maybe someone here knows what it is?

Thanks

Sweep generators, especially the lower cost versions foisted on the television repair people, are peculiar items. In order to sweep the frequency over a wide range, purely electronic methods fall short. So what they use is some electromechanical device to vary inductance or capacitance. I have seen loudspeakers used, for instance, in these sweeper units.

I'm sure that's what is in that 'mod' unit.

The 615 is actually all electronic - or so the manual clams. I restored a 615 not too long ago, but I didn't dig into the sweep circuit deep enough to uncover that little mod unit thingy.

Thanks guys. Yes, it is electronic sweep. After studying this thing some more, I still cannot find the stub of a broken lead on that mod unit. It only has 2 wires coming out of it. If someone with 615 could take a look and see what R109 is actually hooked to it would be much appreciated.

Thanks

I suspect that the MOD unit is not all electronic.