Equipment information:

Harvey-Wells Electronic T-90 Transmitter
Manufacturer:
Harvey-Wells Electronic
Model: T-90
Date:
Category: Radio, Communication
Group: Transmitter
Description: 90 WATT TRANSMITTER
Information:
                                    The Harvey-Wells T-90 Bandmaster is a versatile VFO and
crystal controlled, bands witching transmitter designed for
use in mobile, portable or fixed installations. It provides
RF output on all amateur frequency bands from 3« 5 to 29.7
mcs , inclusive. The maximum input to the PA stage is 90
watts, CW-ICAS, or it may be operated phone with an input of
75 watts maximum«.
The RF section consists of an oscillator stage followed by
two amplifier-multiplier stages which provide excitation to
the final amplifier stage. The oscillator is of the variable
frequency type but may be operated crystal controlled as an
alternative» The VFO dial scale is calibrated*to the output
frequencies. A three position tap switch in the second
multiplier stage permits adjustment of the PA grid drive by
varying the screen voltageo A protective clamping circuit is
provided to hold down the screen of the Power Amplifier
should excitation fail. The PA plate is coupled to a Pi
network output circuit which is designed to work into a wide
range of antenna load impedances.
The modulator system includes a speech amplifier stage
followed by an amplifier-driver stage which supplies driving
voltage to push“ pull modulators. An internally located two
position slide switch modifies the speech input so that
either carbon, crystal, or high impedance dynamic
microphones may be used· When using carbon microphones,
microphone button voltage is automatically developed in the
speech tube cathode The overall modulation system is
designed for maximum response in the speech range for
increased side-band power.
The T~90 Bandmaster is a complete transmitter, factory wired
and tested, including tubes, less power supply«.
Some of the special features are:
a. TVI Suppression
b. Receiver Muting or Disabling
c. Remote Control Connections
d. Push-to-Talk Operation
e. Zero Beating without Carrier On
f . Antenna Changeover Relay
The heater system of the T-90 is wired in a balanced series-
parallel arrangement and filaments may be operated with
either 6 or 12 volts AC-DC input simply by properly wiring
the power input connector for the correct operating voltage.

These manuals are available for the above equipment:

Harvey-Wells Electronic -- T-90 -- Service and User Manual
File name: Harvwels-6980-Manual-Page-1-Picture
Manual Type: Service and User Manual
Pages: 62
Size: 8.91 Mbytes (9339526 Bytes)
Language: english
Revision:
Manual-ID/Number:
Date:
Quality: Scanned document, reading partly badly, partly not readable.
Upload date:
MD5: 3002567d8a702dfa83b70a5734e7a47a
ed2kID: 4d3ea6f0bf5e7f47f91ed29d2431d6c1
Downloads: 43 since 06 August 2015
Information:
SECTION I GENERAL DESCRIPTION
Page
1. General ................................. . 1
2. Electrical Specifications . . . . .................. . . 2
3. Circuit Description . . . . . . .... « ... . 3
SECTION II INSTALLATION
1. General .................... 8
2. External Connections .............. 8
3. Installation ................... 10
SECTION III OPERATION
1. Panel Control Functions
.................................................15
2. Tuning and Operating .............. 16
3. Phone Operation
..............................................................19
4. CW Operation ................. 19
5. Crystal Control Operation ............ 20
SECTION IV ALIGNMENT AND SERVICE
1. General .................... 21
2. VFO Alignment ................. 21
3. Exciter Stage Alignment ............. 22
4. Service
...............................................................................23
SECTION V ANTENNA. INSTALLATION
1.
General................................................................
29
SECTION VI
MISCELLANEOUS INFORMATION
Page
1. Car Systems ........ . ......... . 38
2. The Use of the T-90 as an Exciter ......... 38
3. TVI ...................... 38
ELECTRICAL PARTS LIST
......................................................... . 40
Harvwels-6980-Manual-Page-1-Picture
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