Marconi TF995A & TF995A/1 
TF 995A & TF 995A/1 FM AM Signal Generator


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Marconi TF995A & TF995A/1 FM AM Signal Generator

Signal Generator Type TF 995A is a.c. mains operated and transportable.

This generator has a crystal standardized frequency range covering from 13.5 to 216 Mc/s in four bands.

Its open circuit output level is variable in 1db steps, from a minimum of 0.1 micro volts to a maximum of 100 mV at 52 ohms and 200 mV at 75 ohms.

The output may be c.w, frequency modulated, amplitude modulated, or simultaneously both frequency and amplitude modulated.

Marconi TF995A.jpg (21000 bytes)

The modulation obtained either from an internal 1,000-c/s oscillator or from an external source, is variable to maximum frequency deviations ranging from 25 to 600 kc/s for f.m. and to depths up to 5% for a.m.

Power Unit
A full-wave rectifier provides all d.c. h.t. requirements; in the case of the reactor and r,f. oscillator valves the h.t. is neon stabilized.
The primary of the transformer is tapped to allow for operation from 100 to 150 volts or 200 to 250 volts.
R.f. filtering is introduced into the a.c. input circuit.

Manual and Circuit
available Details Below
On Paper CD or Download

Click Here


The Information Consists of  the Following

The Manual contains all circuits for the : -

Marconi FM AM Signal Generator TF995A 

 
DESCRIPTION
 
GENERAL
 
DESIGN DETAILS
 
OPERATION
 
INSTALLATION
 
MAINS INPUT ARRANGEMENTS

Supply voltages, 200 to 250 volts 
Supply voltages, 100 to 150 volts 

SWITCHING ON AND WARMING UP

CONNECTING TO EQUIPMENT UNDER TEST 

TUNING 

The Crystal Calibrator and its use in standardizing the frequency scale 
Use of the incremental tuning dial 

SETTING UP FOR C.W. OR MODULATED OUTPUT 
Continuous Wave 
Amplitude Modulation 
Frequency Modulation 
Simultaneous Frequency and Amplitude Modulation 

R.P. OUTPUT ARRANGEMENTS 
Outputs from 1 uV to 100 mV at 52 and 75 ohms 
Outputs from 2 uV to 200 mV at 75 ohms only 
Outputs from 0.1 uV to 10 mV at 52 and. 75 ohms 
Output in terms of voltage developed across an external load 
Matching to external loads other than 52 or 75 ohms 
Matching to balanced loads 

SYNCHRONIZING - SIGNAL 

OPERATIONAL SUMMARY 

MAINTENANCE 

GENERAL 

REPLACEMENT OF VALVES AND CRYSTALS 

WORKING VOLTAGES 

ACCESS TO ENCLOSED SUB-ASSEMBLIES 

R.F. Unit 
Fine Attenuator 
Coarse Attenuator 
Mains Input Filter Unit 
Power Unit 

REPLACEMENT OF COMPONENTS OF SPECIALLY SELECTED VALUE 

SCHEDULE OF TESTS 
Apparatus Required 
Insulation 
Hum Level 
Crystal Oscillator 
Basic Oscillator 
Frequency Multipliers 
Accuracy of the R.F. Output Voltage 
Modulation Oscillator 
Frequency Deviation 
F.M. Distortion 
Deviation Range Adjustments 
Deviation Monitor Circuit 
High Deviation 
External F.M 
Internal A.M 
External A.M. 
Spurious A.M. 

APPENDICES 

VALVE REPLACEMENT DATA 

COMPONENT LAYOUT ILLUSTRATIONS 

SPARES ORDERING SCHEDULE WITH CIRCUIT REFERENCES 

BLOCK SCHEMATIC DIAGRAM 

COMPLETE CIRCUIT DIAGRAM 

DECIBEL CONVERSION TABLE

TF995A 1.jpg (27790 bytes)

Manual and Circuit
available Details Below
On Paper CD or Download

Click Here

TF995A 2.jpg (29624 bytes)


If your model is the TF 995A it will have a valve line up as below

If it is the TF 995A/1 it has an extra valve a 12AT7 double triode

Six: Type EF95 Pentodes.
Two: Type 6AK6 Pentodes.
One: Type 6AU6 Pentode
One: Type QS15O/15 Voltage Stabilizer.
One: Type 5Z4G Full Wave Rectifier,
One: Type D77 Double Diode.

If your model is the TF 995A/5  it will have a valve line up as below

Six; Type 6AK5, Pentodes.
One: Type 6AK6, Pentode.
One: Type 6AL5, Double Diode.
One: Type 6AU6, Pentode.
One: Type EF86, Pentode.
Two: Type 12AT7, Double Triodes.
One: Type 5Z4G Full Wave Rectifier.
One: Type OA2, Voltage Stabilizer.
One: Type 5651, Voltage Stabilizer.

Marconi TF995A FM AM Signal Generator 1954 vintage and TF995A/1 1955

For the TF995A/5 a later 1960 model Click Here

Manuals are Available Worldwide as a Download on CD or Paper Copy.

Manual including circuit 95 pages

Manual 95 A4 pages worldwide

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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.


Manuals are Available Worldwide as Paper Copy on CD or as a Download

Thank you for your interest. Allen and Alanna G0RIT
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Revised: January 20, 2016