Adjusting Procedure Of Each Section - Sharp LC-20B2H Service Manual

ADJUSTING PROCEDURE OF EACH SECTION

The best adjustment is made before shipping. If any position deviation is found or after part replace is performed, adjust
as follows.
1. Preparation for Adjustments
(1)Use the exclusive-use AC adapter or stable DC power supply.
AC adapter: UADP-0219CEZZ
DC power supply: 13 ± 0.5V 3.5A
[1] Adjustment Procedure
1-1. Adjusting the checker
Turning on the power (initialization) ) Setting the model and size in inches ) Transferring the model-specified
data to the E 2 PROM (I
1-2. Adjusting the finish process
Reassembling the set ) Turning on the power ) Calling the adjustment process mode (using the remote
controller) ) Adjusting the counter bias, TV contrast and white balance
[2] Calling the MAIN adjustment process mode
There are the following two ways to choose from.
• Set KEY 4 and KEY 5, pins (81) and (82), respectively, on the microprocessor to the "L" level. Now turn on
the power.
• For servicing, hold down the INPUT SELECT and MENU keys at once, and turn on the POWER switch. (Make
sure the process mode "K" appears at the top left of the screen.) Then press the CH DOWN and VOL DOWN
keys at once. (Make sure the adjustment process mode screen shows up.) To quit this mode, turn off the power.
(Or turn off the POWER switch or use the remote controller's OFF key.)
[3] Using the keys for the adjustment process
Selecting a reception channel
• Using the CH UP/DOWN key, turn up and down reception (broadcasting) channels.
Just click on the key, and channels are selected on by one.
Hold down the key, and the next receivable channel is searched up and down.
• Adjustment items
Adjust each of the items by using the MENU SELECT, CURSOR UP/DOWN, CH UP/DOWN and VOL UP/
DOWN keys (on the set or on the remote controller).
• Select an adjustment item using the CURSOR UP/DOWN key.
• An adjustment item is toggled on and off by activating the MENU SELECT key (next item).
Let's suppose that the item at the bottom of a page is now selected. When the MENU SELECT key is activated
here, the item at the top of the next page will be selected.
[4] Initialization
4-1. Set pins (81) and (82) of IC2001 (microprocessor) to GND. Turn on the power.
4-2. Select a model number ( C2H, B2H ).
4-3. Select a size in inches ( 10, 13, 15, 20 ).
[5] Adjustment
5-1. +B adjustment (R3760 Variable resistor)
1) Receive the colour bar signal.
2) Adjust the voltage at SC3403 (pin (38)) to 5.00± 0.02 V.
Note: The 5.0 V level is used as reference for all the line voltages. Make this adjustment as precisely as
possible.
5-2. Counter bias adjustment: COM BIAS on page 2
Adjust the "COM BIAS" setting until the contrast gets optimum (the black portion blackest). The adjustment
guideline is around 106 for Model LC-20B2H/M.
C) ) Calling the adjustment process mode ) Starting the adjustment (+B)
2
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LC-20B2H
LC-20B2M