Circuit Description; D8/A8 Chassis Alignment Procedure; Assembly Adjustment - Hitachi CL32W30TAN Wartungshandbuch

CIRCUIT DESCRIPTION

D8/A8 CHASSIS ALIGNMENT PROCEDURE

APPLICATIONS
THIS SPEC. SHOULD BE APPLIED TO ALL UK AND EXPORT, A8 RECEIVERS
P.W.B ASSEMBLY ADJUSTMENT
FOR SIGNAL
PREPARATION ADJUSTMENT
•
+B adj. VR982..........Centre
•
Screen VR (FBT).......Counter-clockwise fully
•
Turn on set. Adjust +B to approximately 152V. (Pre adjustment only - final adjustment in +B VOLTAGE ADJUSTMENT
section)
•
If flaring is observed adjust L501 until a clean video signal is seen on the oscilloscope video out port.
For models which have a flash device fitted, ensure that the service information reads FLASH: x.x instead of Code: x.x for the
software version.
STANDARD AFC ALIGNMENT
To reduce the influence of circuit temperature drift, let the television warm up by leaving it operating normally for more than two
minutes.
•
Receive a 'PAL I' signal by selecting program 3 via the remote control handset.
•
Receive a signal level of +60 dBuV at 623,25MHz (CH40) by direct frequency entry under the CH option.
•
Set AFC offset (in service - options) to the centre position.
•
In the tuner menu select standard I.F AFC and press either '<' or '>' on the remote control to activate the automatic AFC
setting procedure.
•
If the indicator bar goes either end, then returns to the centre, adjust L201 one turn and then return to step 3, continue this
until the indicator bar no longer jumps back to the centre.
L' AFC ALIGNMENT (FOR EXPORT MODELS ONLY).
•
To reduce the influence of circuit temperature drift, let the television warm up by leaving it operating normally for more
than two minutes.
•
Receive an L' signal by selecting program 14 via the remote control hand-set.
•
Receive a signal level of +60 dBuV at 63,75MHz (CH4) by direct frequency entry under the CH option.
•
In the tuner menu select L' I.F AFC and press '<' or '>' on the remote control.
•
If the bar goes to either end then returns to centre, adjust L201 one turn and then return to step 3, continue this until the
indicator bar no longer jumps back to the centre.
Because the set up procedures are interactive it is necessary to repeat all procedures from STANDARD AFC ALIGNMENT until no
adjustment of L201 is required.
AGC ALIGNMENT
•
To reduce the influence of circuit temperature drift, let the television warm up by leaving it operating normally for more
than two minutes.
•
Connect a voltmeter of at least 100K internal resistance to the A.G.C. terminal of the tuner.
•
Receive channel 40 (623.25mhz) at +60dBuV.
•
Adjust the A.G.C. using the A.G.C take-over option in the tuner sub menu until the A.G.C. voltage is 2.8V +/- 0.1V.
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