AN/URT-3 Restoration Project - RF amplifier

Restoration Progress pages

RFA - RF amp

LLRM - 100w Modulator

RFO - Oscillator

            LVPS - Low Voltage power supply

MVPS - 100w HV power supply

Transmitter Cabinet

            HLRM - 500w modulator

HVPS - 500w HV power supply

Booster Cabinet

Acquired 3/19/2008 - a 500 watt, 136 tube, autotune HF AM/CW/FSK transmitter
Page 1 - initial cleanup - see below
Page 2 - deeper into the guts of the RFA

RFA - RF amplifier - 4-400 PA output driven by 5933 IPA (ruggedized 807)
50 ohm output - antenna matching is handled by external tuner

rfa-07.jpg (39408 bytes)
RFA front panel
p1010031.jpg (57837 bytes)
top view
4-400 chimney upper left
p1010032.jpg (58521 bytes)
vacuum variables
HF tank coils below
p1010033.jpg (61933 bytes)
PA autotune drive motor for vacuum variables and MF coil slugs
p1010034.jpg (62790 bytes)
meters and bandswitch drive motor
p1010035.jpg (59161 bytes)
left side - big slug-tuned MF coils
p1010036.jpg (63353 bytes)
output RF sensor and internal dummy load
p1010037.jpg (62941 bytes)
uh-oh - removed the bottom cover
p1010038.jpg (61633 bytes)
HF tank coil nest
p1010039.jpg (58590 bytes)
HF tank coils after cleaning
p1010040.jpg (64214 bytes)
more mouse nest- this time stuffed into the autotune sequencer control relays and switches
p1010041.jpg (63854 bytes)
p1010043.jpg (63181 bytes) p1010044.jpg (58455 bytes) p1010045.jpg (58416 bytes)
only a little corrosion on gears - not serious
p1010046.jpg (60599 bytes)
p1010047.jpg (58706 bytes) p1010048.jpg (55997 bytes)
microswitch that steers output to internal dummy load or external antenna
p1010049.jpg (60465 bytes)
driver (IPA) side - motor tuned IPA input and output cap
p1010050.jpg (61779 bytes)
p1010051.jpg (62042 bytes)
IPA RF sensor, autotune motor, and switch cams
p1010052.jpg (60467 bytes) p1010053.jpg (58462 bytes) p1010054.jpg (56482 bytes)
crack in vacuum variable?
p1010056.jpg (63840 bytes)
after an hour of vacuuming and air hose work, there was still stuff coming out of the autotune sequencer
p1010057.jpg (31634 bytes)
epoxy? pieces that fell out when cleaning