SERVICE ADJUSTMENTS
~ ‘AFETypREcAuT’oNs ~
-—
.
An Isolation transformer should be connected in the power Iine between the receiver
and the AC Iine before any service
is performed on the receiver.
I
r
X–RADIATION l=REC2AUl_10N.
X-RADIATION PRECAUTION The primary source of X-RADIATION in the television
receiver is the picture tube. The picture
tube is specially
constructed to limit X-radiation emissions.
For continued X-RAD IAT 10N protection, the replacement
tube must be the same type as the original
including suffix
letter.
Excessive high voltage may produce po$en;;~~
hazardous X-RAD IAT 10N. To avoid such hazards,
the high voltage must be maintained within specified limit.
this service manual, high voltage for specific
high voltage limits. If high voltage exceeds specified
limits, take the
necessary corrective action. Carefully follow the instructions
for high voltage
check to maintain the high voltage
within the specified limits.
(l)AGC ADJUSTMENT
NOTE: Do not attempt this adjustment with weak signal.
1.
2.
3,
Tune receiver to most clearest (or strongest) UHF
station in your area.
Set brightness and contrast controls to maximum.
Set coiour control to minimum,
Set the AGC (VR1OI) control to mid-range.
Turn AGC control in direction which causes snow to
appear, then in the opposite direction until the snow
just disappears,
(2) VIDE0 DET. ADJUSTMENT
1, Receive colour bar pattern.
2, Connect oscilloscope to test point TP-F.
3, Adjust VR121 for l. OVp-p of video detector waveform.
(3) I= AI- COLOUR AD JUSl_MENl_
Recleve colour bar pattern.
Set controls : brightness...maxmax.
colour, ,,, . ... ..max.
contrast ... .....middle range
~
Connect the oscilloscope to TP-6B on CRT PCB.
11. VR251,T281 I Ad,ust VR251,T2&31 toobtaineachlil
waveform (amplitude) for the same as
shown below
—
B-Y waveform Fig.1
2. T211 Adjust T211 to obtain proper
waveform as shown above.
NOTE: (l)+B1 VOLTAGE IS AUTOMATICALLY
SET AT 135 V. AND NO NEEO TO
AOJUST .
(2) SOME OF THE CHASSIS HAVE NO PIN
CUSHION CORRECTER CONTROL(VR482).
(VR 482 IS REPLACEO TO THE SOLID
RESISTER. )
(4) GREY SCAI-EAND TRACKING
ADJUSl_MENT
Tune the receiver to monochrome test pattern.
1, Set brightness and colour to normal contrast to minimum.
2. Connect the service tip to KSV-2 (service condition).
3. Set screen control to minimum. (fully counterclockwise).
4. Turn screen control to obtain just visible one coloured line,
5. Adjust each bias (VR621-Green. VR601-Blue, VR611-Red)
controls alternately until a dim white line produced.
6 Re-connect the service tip to KSV-1 (normal condition).
7,8.Adjust red (VR612) and blue (VR602) drive controls
alternately to produce normal black and white picture.
Check for proper grey scale tracking at all brightness levels.
NOTE:lf grey scale adjustment is made after picture tube
replacement, check high voltage and subbrightness
adjustments.
(5)S”6 BRIGHTNESS ADJUSTMENT
1. Connect a DC meter between ‘TP-H’ (positive lead) and
‘TP-G’ (negative lead) on main unit.
2. Tune the receiver to monochrome circular pattern.
3. Set brightness to maximum and contrast to minimum.
4. Adjust sub brightness control (VR211) for 0.35V.
NOTE: If picture tube is replaced, check sub-brightness adjustment.
(6)HIGH VO1-l_AGE CHECK
1. Tune receiver to monochrome circular test pattern.
2. Set brightness and contrast to maximum.
3. Connect a high voltage probe to anode lead at picture tube.
4. High voltage must be measured between 26-27 kv.
NOTE: If the picture tube is replaced, check high voltage.
(7) HORIZONTAL CENTER ADJUSTMENT
1. Tune the receiver to monochrome circular test pattern,
2. Set the brightness and contrast to maximum.
3. Adjust Video Phase (VR411) for optimum horiz. center position.
(E$)TUNING DISPI-AY WIDTH ADJUSTMENT
1, Tune the receiver to monochrome circular test pattern.
2. Set the mode switch on the front panel to ON.
Tuning bar is displayed on screen.
3. Adjust VR750 for the optimum tuning bar width.
Set the mode switch to off.
(9) VERl_ 1 CAl_ ADJUSTMENT
1.Tune the receiver to monochrome circular test pattern.
2.Adjust vertical size (VR451) control for full scan.
(10) FOCUS AD JUSl_MENT
Adjust focus control on the f Iyback transformer for wel I
scanning line,
ll)PIN CUSHI ON CORRECT I ON
-2”
Adjust the pin cushion correcter control VR482 to correct the pin
cushion distortion of the picture.