Hallicrafters SX-117, Руководство по ремонту

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7, SUBSYSTEM TEST AND EVALUATION
BE AWARE: The voltage and signal levels in all of the subsystem charts apply to production run
3 and above radios. Unmodified run 1 and run 2 radios will vary greatly.
7-1, AVC FUNCTION TEST
7-1-1, AVC TRACKING
BE AWARE: the AVC will track differently from radio to radio. Minor differences in gain in each
stage of the receiver train will affect the slope of the input voltage to AVC voltage curve. The
following data was taken from an above average receiver and a just in spec receiver. Properly
functioning receivers should fall somewhere within this range. If, with no signal on the
antenna and the RF GAIN set to zero, the AVC does not fall b0.20 and +0.65 vdc there
is a fault.
Set up the receiver on the 80-meter band and tune up in LSB mode at 3.900 MHz.
1, Allow 15 minutes warm up.
2, Turn RF gain to zero. Adjust meter zero pot for 0 on the S-meter.
3, Turn RF gain to max.
4, Set generator for 50 microvolts output @ 3.900 MHz.
5, Set AF gain for 500 mw out. Set factory gain pot for S9 on meter.
RF @ THE ANTENNA AVG VOLTAGE
Measured at the tie point of R65 and C81
S-METER
Above average
receiver
TEST UNIT 1
Above average
receiver
TEST UNIT 2
Marginal / in spec
receiver
For baseline test set
Rf gain set to min
J1 GROUNDED
0.300V 0.560v Zero
SET RF GAIN TO MAX
O.5uv 0.280 O.560V S-1
5.0uv -1.430 -0.920v S-3
50uv -4.090 -3.480v S-9
500uv -5.620 -4.400 15db
5000uv -6.830 -5.600v 35db
50,000uv -8.540 -6.800V 55DB
100,000UV -9.500 -7.600V 60DB