🚀 go-pugleaf

Ladies and Gentlemen of the net:

	I have a terrible problem...my RCA BTA 50-J AM transmitter
just ate one of its MC899 logic chips.  Fortunately for me, I
could adapt this circuit to use TTL (works, too at 3.6 volts)
but there are plenty more of these beasties which depend on
the characteristics of this family for waveshaping, etc.

	The logic chips are part of the "Ampliphase" exciter
modulator card (as opposed to the drive regulator, oscillator,
and reflectometer which are not nearly as packed with DTL).
A triangle wave is generated inside which is summed with the
incoming audio, and then "clipped" to form pulses of variable
width and hence phase (and hence Ampliphase at the antenna
output...).

	Are there sources (even MIL/JAN parts are fine) for
MC-8xx family spares?  RCA-GE doesn't have them.  If this
exciter were to lose another one, I'd have to convert it back
to its vacuum tube counterpart (blecch, hock-ptewey).

	Of course, if you have a "spare" BTE-20 exciter gathering
dust in your junk box, I'd be interested in that, too. My
transmitter came from WHN New York (now WFAN) but the "broker"
swiped the second exciter and the spares.

Yours for $5000/mo power bills,

York David Anthony
KGOL Humble-South Houston, Texas