Marconi Carrier Deviation Meter TF 791C

Circuit Diagram, Service Manual, Service Information,  Schematic Diagrams and Manuals

For Repairing, Restoration and Servicing of Vintage and Modern Electronic Equipment

Manual Circuit and
Operation Instructions
available Details Below
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Click Here

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The TF 791C is a direct reading instrument having deviation measurement ranges of 5, 25, 75, and 125 kc/s full-scale.

The modulation-frequency range extends from 50 c/s to 35 kc/s.

The calibrated carrier-frequency range is 4 to 270 Mc/ s but, by the use of local oscillator harmonics, the instrument can be employed up to 540 Mc/s.

Deviation is read on a panel meter, in addition front panel terminals fed from a separate output stage provide an outlet for the products of demodulation.
They permit external aural or visual monitoring of the modulation of the signal under test.

High measurement accuracy is ensured by the provision of built in facilities for generating a crystal controlled signal, which serves as a deviation standard.

DESCRIPTION

GENERAL
DESIGN DETAILS 

OPERATION

INSTALLATION

SWITCHING ON AND WARMING UP

SETTING UP DEVIATION METER AND MAKING A MEASUREMENT

Standardizing Deviation Scale 
Applying Signal to be Measured
Tuning, Checking Input Level, and Reading Deviation  

ASYMMETRIC MODULATION AND CARRIER SHIFT.

MEASUREMENTS ABOVE 270 Mc/s

SETTING UP DEVIATION METER AT SUPPLY FREQUENCIES OTHER THAN 50 c/s

USE OF L.F. OUTPUT TERMINALS

OPERATIONAL SUMMARY

MAINTENANCE

GENERAL

FUSES

REMOVAL OF CASE
 
MAINS INPUT ARRANGEMENTS
For Supply Voltages from 180 to 250 volts 
For Supply Voltages from 100 to 150 volts 

ACCESS TO SUB -ASSEMBLIES

Power Unit
Integrating Filter
Local Oscillator and Mixer
Coil Turret

WORKING VOLTAGES

REPLACEMENT OF VALVES AND CRYSTALS 

PRESET AND SPECIALLY SELECTED COMPONENTS

SCHEDULE OF TESTS

Apparatus Required
Power Unit
I.F, Amplifier and Limiter 
Counter Linearity
Meter Zero 
L. F. Amplifier and Valve Voltmeter
Tuning Dial Calibration
Oscillator Output
Minimum B. F. Input Leval
I.F. Traps
Overall Hum and Noise 
Deviation Reading 

DIAGRAM IN TEXT

MAINS INPUT CONNECTIONS

APPENDICES

VALVE REPLACEMENT DATA

COMPONENT LAYOUT ILLUSTRATIONS.

SPARES ORDERING SCHEDULE WITH CIRCUIT REFERENCES

BLOCK SCHEMATIC DIAGRAM

CIRCUIT DIAGRAM

Manual Circuit and
Operation Instructions
available Details Below
As a Download
Click Here

We do all we can to provide the very best that is available for you.
But in the unlikely event that any data should not be as you expected.
A refund is always available. Kind Regards Allen and Alanna.