SHARP 21BM2GMK2
Manual de Servicio

ADJUSTMENT PRECAUTION: PURITY ADJUSTMENT Make sure TV Set is in "Normal Condition" before switch to service mode for adjustNo. point Adjusting procedure/conditions Waveform and others ment.
1 PURITY ADJ. 1. Receive GREEN-ONLY signal. Adjust the beam current to about 700 µA. 2. Degauss CRT enough with the degausing coil.

PIF ADJUSTMENT field and keep the static convergence roughly
adjusted. 4. Observe the points a, b as shown in Fig. 4-1 No. point Adjusting procedure/conditions Waveform and others through microscope. Adjust landing to the

a b 3. Maintain purity magnet at the zero magnetic

1 Tuner IFT 1. Get tuner ready to receive the CH. E 9 rank A requirements.

5. Orient the raster rotation to 0 eastward.

Fig. 4-1 ( PRESET ) signal,but with no signal input.

2. Connect the sweep generator's output cable to 10k 1n60 1000p » Tightening torque: 108 20 N (11 ± 2 kgf)
Oscilloscope IF OUT

Adjust PLL data. 6. Tighten up the deflection coil screws.

tuner antenna. ( RF SWEEP ) 7. Make sure CRT corners landing meet the A

3. Adjust sweep generator's to 80dBuV. rank requirements. If not, stick the magnet sheet A 4. Connect the response lead ( use LOW IMPEDto correct it.

100k 75ohm

5. Set the RF AGC to 0 6 V no saturation with
P C
-1.5+/-0.8dB

ANCE probe with wave detector ; see Fig.1 ) to Note: This adjustment must be done after tuner's IF output terminal. ( This terminal Fig.1 warming up the unit for 30 minutes or B must have the probe alone connected ). longer with a beam current over 700 E-9 CH µA. A = B the waveform. shown in Fig. 2. Fig. 4-2

* For the following colours press R/C RGB key to

6. Adjust tuner IF coil to obtain the waveform as change.

Note: Be sure to keep the tuner cover in position (on right of the CRT)

Green-only Blue-only Red-only Rank "A"

Fig.2

during this adjustment.

Signal-colour screen cleared 2 RF-AGC 1. Receive "PAL COLOUR BAR" signal. Note: For the 50 ohm signal

7
» Bias box: About 4.5 V * Press R/C RGB key for 1 secFig. 3

TAKE OVER » Signal Strength: 57 ± 1 dBµV (75 ohm open) strength gauge, when not A POINT AD2. Connect the oscilloscope to TP201 (Tuner�s AGC u s g 0 / 7 5 i m p d a n c e JUSTMENT Terminal) as shown in Fig. 3. adapter, signal strength is (I C BUS 52±1dBµV(75 ohm open), inB2 CONTROL) Oscilloscope stead of 57±1dBµV (75 ohm

0.1V Precaution: The loss of using

+ TP201 open). A = B

� impedance adapter

Bias box TV Set Fig. 4-3 (on left of the CRT)

+ Rank "A"

�

3. Call "AGC" mode in service mode. Adjust the

"AGC" bus data to obtain the Tuner output pin drop 0.1V below maximum voltage.

ond in NORMAL MODE, the colour will change to RGB mono colour mode.

4. Change the antenna input signal to 63~67dBµV,

and make sure there is no noise.

5. Turn up the input signal 90~95 dBµV to be sure

The TEXT "R. G. Cy" Key can be directly use to change to other colours screen.

that there is no cross modulation beat.

21BM2GMK2

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