Bob wrote:

On 29 Sep 2013 22:39:59 GMT, Jim Mueller wrote:

I don't know for sure what your things are, but judging from the labels
stamped into the case, I think they might be TV tuners or modulators or
perhaps a corresponding part for satellite TV. Perhaps they are a
similar part for some other application.

I am assuming, perhaps wrongfully so, that since they were made for Lear Jet,
they are the front end of one of their radio receivers, whether it be for the
aircraft band, or locator/directional beacons possibly. That's just a wild
guess. I wrote to Mitsumi requesting information, but I haven't received a reply
from them. Lear Jet is another possibility, but they have since been taken over
by another company, and as these are older parts, there may not be any
information available any more. I was hoping someone in this group may have come
across them in the past. Thanks anyway..


I don't think Mitsumi ever made areospace rated electronics. It
doesn't fit with their low cost, high volume operations. the costs to
certify the equipment is very high, and the shielding on those boxes
would never pass the required tests.

Mitsumi has made hundreds of this type module, and a lot were
proprietary. Probably from their Lear series of 4 or 8 track tape
players. They developed the first 12 volt powered playback decks for
broadcast cartridges. Later, the 8 track was developed to lower
manufacturing costs by placing a cheaper roller in each cartridge. That
eliminated the precision machining needed to raise and align the pinch
roller. Early car tape units were mechanical crap.

If you have a lot of them, you might look in the old Sams AR series
manuals for something that uses them but that's tens of thousands of
pages.

--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.