Hi All,
When I looked carefully (pic time_step-01.jpg in files/DFC-7), the mixer is definitely Texas Instruments, and I thought I could make out "SN7651?". Did a search and came up? with a data sheet for a SN76514 balanced mixer. Function and pin-outs match the schematic for the DFC-7, and part was around when the FRG-7 was produced, so I'm calling this as THE part number for IC1.
Have put the datasheet in files/DFC-7.
Cheers,
Steve
