MAGNADYNE ALFA BE1022 CHASSIS T122 CRT TUBE PHILIPS A31-410W.

TELEVISION TUBE A31-410W

QUICK REFERENCE DATA

31cm (12in) rectangular direct viewing television tube. A separate safety
screen is not required. Especially for use in portable receivers with push-
through presentation.

A special feature of this tube is its short warm—up time.

Deflection angle 110 deg
Final accelerator voltage max. 15 kV
Neck diameter 20 mm —u-

Light transmission 50 % E

Maximum overall length 233 mm

A legible picture appears within 5 seconds (typ. )

This data should be read in conjunction with
GENERAL OPERATIONAL RECOMMENDATIONS — TELEVISION PICTURE TUBES

HEATER
Vh 11  V
Ah 140 mA
Cathode warm —up time (typ. ) 5 s

OPERATING CONDITIONS

Va2, a4 12 kV
VG3 (focus electrode) control range 0 to 350 V
V  A1 250 V
Vg for visual extinction of focused raster  -35 to -69 V
*Vk for visual extinction of focused raster 32 to 58 V

*For cathode modulation, all voltages are measured with respect to grid.

SCREEN
Metal backedFluorescent colour White
Light transmission (approx. ) 50 %

Focusing Electrostatic

DEFLECTION Magnetic
Diagonal deflection ‘angle  110 deg
Horizontal deflection angle 99 deg
Vertical deflection angle 80 deg

The deflection eons should designed so that their internal contour is in accordance
with the reference line gauge shown on page 4.



CAPACITANCES:
cg all 7. 0 pF
ck all 3. 0 pF
ca2 a4 m 450 to 900 pF
a2,a4 —B 150 PF

EXTERNAL CONDUCTIVE COATING
This tube has external conductive coating, M, which must be connected to chassis.
and the 'capacitance ‘of this ‘coating to the final anode is used to provide smoothing
for the eht supply.
 The electrical connection to this coating must be made within
the area specified on the tube outline drawing;

RASTER CENTRING

See notes under this heading in ' General Operational Recommendations - Television
Picture Tubes' .

Centring magnet field intensity 0 to 800 A/m
Maximum distance of centre of centering field from reference line 47 mm

Adjustment of the centring magnet should not be such that '3. general reduction in
brightness of the raster occurs.

REFERENCE LINE GAUGE see page 4
MOUNTING POSITION Any

The tube socket should not be rigidily mounted but should have flexible leads and be
allowed to move freely.

This ‘tube is fitted with a pin protector in "order to avoid ‘damage to ‘the glass base
due to bending of the base pins whilst handling the tube.

it is advisable to keep this pin protector on the base until it can be replaced by the
socket after the installation of the tube in any equipment.

TELEVISION TUBE A31-410W

RATINGS (DESIGN MAXIMUM SYSTEM)

Va2 a4 max. (at i=0 a2 a4) (see note 1) 15 kV
Vva2 a4,“ min, 8.5kv
va3 max. 500 V
-Va3 max. 50 V
Va1 max. 350 V
va1 min. 200 V
~vg(pk) max. (see note 2) 350 V
~Vg max. (see note 3) ~ 100 V



Adequate precautions should be taken to ensure that the receiver is protected
from damage which may be caused by a possible high voltage flashover within
the tube. '

Maximum pulse duration 22% of one cycle with a maximum of 1. 5ms

The d. c. value of bias must not be such as to allow the grid to become positive
with respect to the cathode, except during the period immediately after switching
the receiver on or off when it may be allowed to rise to +2. OV. It is advisable to
limit the positive excursion of the video signal to +5V(pk) max. This may be
achieved automatically by the series connection of a 10kohm resistor.

. The metal hand must be earthed by means of the tag provided.

The mounting lugs will not necessarily be in electrical contact with the metal
band.

Weight tube alone (approx. ) 2. 8 kg