Sharp LC-12A2E Service Manual page 9

[4] Initialization
4-1. Connect the 81 pin and 82 pin of IC2001 (microcomputer) to GND, and turn on the power.
4-2. Select the model name (A2E/A2E(K)).
4-3. Select the inch size (12).
4-4. Return the 81 pin and 82 pin of IC2001 (microcomputer) to the original state.
[5] Transmission data by model
Transmission data
Model
[6] Adjustment
6-1. +B adjustment
1) Receive the E-12CH (PAL color bar).
2) Adjust the voltage of the 49 pin of SC401 to 5.00V±0.02V.
Note: Since 5.0V is a reference voltage of all power voltage, adjust it precisely.
6-2. 38.9-VCO adjustment
1) Set the sound system to the B/G mode.
2) Send the CW signal of 38.9MHz, 90dBµV from SG to TP3201 (IF-OUT).
3) Adjust the L3231 coil so that a voltage of 2.5±0.2V is obtained at TP3203 (AFT).
Note 1: The input impedance of the digital voltmeter must be 1MΩ or more.
Note 2: To adjust L3231, use a non-magnetic driver.
Note 3: No signal must not be input from the antenna.
6-3. 33.9-L'-VCO adjustment
1) Set the sound system to the L' mode.
2) Send the CW signal of 33.9MHz, 90dBµV from SG to TP3201 (IF-OUT).
3) Adjust the R3233 volume so that a voltage of 2.5±0.2V is obtained at TP3203 (AFT).
Note 1: The input impedance of the digital voltmeter must be 1MΩ or more.
Note 2: After performing the adjustment of the item 6-2, execute this item.
Note 3: No signal must not be input from the antenna.
6-4. RF-AGC cut-in adjustment
1) Set the sound system to the B/G mode, and receive the E-12CH (PAL color bar).
2) Set the antenna input level to 56dBµV (75Ω termination, QP value).
3) Turn the R3231 (AGC volume) clockwise so that the voltage of the TP3202 (RF-AGC terminal) becomes
maximal.
4) Turn it counterclockwise, and adjust the AGC terminal voltage to the point that is lower than the maximal
voltage by 0.5±0.2V.
6-5. Opposed bias adjustment
1) Receive the monoscope pattern.
2) Adjust the "COM BIAS" so that the contrast of the stairway-shaped part may become the biggest.
E2PROM adress Item Write Data
9
LC-12A2E
OSD Display