[Motorola] "Lunchbox" PT400

[Geoff Fors]

There is a different battery box for these which uses just a bunch of D
cells, and I do mean a bunch, but they last a long time and you can get them
on sale at places like Wal-Mart or Costco/Sam's Club.  Those boxes sometimes
show up on eBay, but usually attached to yet another PT400...

The radios can be tested by using just an external power supply, but be
careful because they use Germanium PNP transistors and the polarity is
backwards from what you think.  They expect about 14 volts.

The owners manual is useless.  I haven't seen one in at least 30 years.  It
just tells you how to turn them on and set the squelch.  The service manual
shows up on eBay once in awhile.  Motorola hasn't stocked the manuals in
decades.

The PT400 is basically a PT300 with an added-on transmitter power amp to
give about 10 Watts, and the addition of a metering socket panel.  The nicad
battery box has contacts on the outside end to allow dropping into a charger
rack, which is not featured on the PT300.  The majority of PT400's seem to
have been sold to the US Government.  The PT300 is actually an HT-200
Handie-Talkie in a lunchbox housing with a power amp to give 5 Watts on
transmit.  And, finally, the PT200 is just an HT200 in a lunchbox.

If you do some searching on the net, someone somewhere had a schematic of
the battery box and the power wiring on his website, I just don't recall
where I saw it.


Geoff
WB6NVH