Service Manual Part 1

"8  
  
"8 '(&(
The following equipment is required for functional testing.
• Power supply cord, wired as shown in Section 8.3.
• Power supply adjustable between 9 & 16V DC, with a capacity of at least 8A.
• VHF or UHF signal generator: good quality FM 50Ω, usable from 0.1V (-127dBm) to
200mV (0dBm) pd (e.g. HP8640B, Marconi 2019).
• Frequency counter: 10Hz to 650MHz, 2ppm stability, with at least a 2s time base res-
olution (e.g. Opto).
• Audio signal generator: 600Ω output, -50 to 0dB level, fully adjustable, sine wave
output 10Hz to 100kHz (e.g. Trio 203, HP204C/D).
• FM deviation meter (e.g. Sayrosa 257 or 252), with the following specifications:
- low residual FM
- resolution down to a full scale of 1kHz and a minimum of 10kHz
- maximum positive and negative peak display
- 15kHz low pass filter
- detected audio output facility.
 When using with LTR or DCS, the deviation meter must have a good low fre-
quency response, to avoid incorrect deviation readings.
• Sinad meter or audio distortion analyser, 1kHz notch type (e.g. HP334A, HP339A or
Helper Instruments Sinadder).
• AC millivoltmeter (e.g. Trio VT-106).
• Digital multimeter (e.g. Fluke 75).
• 20MHz dual channel oscilloscope and X10 . X1 scope probes (e.g. Trio CS1022).
• RF power meter, 50Ω; RF detecting element 50W and 5W for appropriate frequency
ranges (e.g. Bird Meter 6154 or 611).
• RF power attenuator, 50Ω, total attenuation 30dB (e.g. Weinschel 40-40-33 30dB,
150W).
• Microphone test box (refer to Figure 4.1).
A multifunction test set may be used as long as it has the appropriate function to per-
form the calibration correctly e.g. Rhode & Schwarz CMS52 Radio Communications
Test Set, with a high stability oscillator.