HP82240A Hardware

[Tony Duell]

(01-20-2014 06:56 PM)TomC Wrote:  Is anyone familiar with the early variants of the 82240A Hardware?

Existing Documentation (the very fine T.Duell schematics) show a KA2183 device as the IR front end IC.

I've disassembled an 82240A and the IR front end is a TDA3047. I have the datasheet for this part, and am curious about the subsequent circuitry in the printer. It appears that the output of the TDA3047 connects to the base of a TO92pkg transistor. Before sliding down the circuit re-construction path, I would be curious is anyone else has traced this circuit and can share their findings.

Thanks,
TomC

I have seen, but not for long enough to reverse-engineer it, a version of the printer using the TDA3047. It may be the -A uses that IC, the -B uses the KA2183.

The TDA3047, as I guess you've found, was a Philips IC. I have at least one data book that includes it. The transistor you mention is probably just a buffer/inverter.