Samsung CKA4217, CKA5227 Troubleshooting

CKA42*7L/5227L 6-1

6 Troubleshooting

Notes: 1. If a picture does not appear, fully rotate the brightness and contrast controls clockwise and reinspect.

2. Check the following circuits.

• No raster appears: Power circuit, Horizontal output circuit, H/V control circuit, and H/V output circuit.

• High voltage develops but no raster appears: Video output circuits.

• High voltage does not develop: Horizontal output circuits.

6-1 No Power

Does proper AC 90-264 Volts

appear between the positive and

negative poles of C604?

Check F601, L602 and TH602.

Check D604~D607, D609, IC602,

T601, OP601, and power circuit.

Yes

Check IC301 and its

related circuits

Check the power supply circuits

(D616)

Check the power supply circuits

(D608)

6-2 Horizontal Line on CRT

Does DC 13 V appear at

Pin 2 of IC301?

Does DC -11 V appear at

Pin 4 of IC301?

Yes

Replace IC301 or check its

related circuits

(D301, IC301 and R312)

Does the output pulse of

48 Vp-p appear

at Pin 5 of IC301?

Yes

WAVEFORMS

45.0 V (IC301, #5)

CH1 P-P = 45.0 V CH1 RMS = 5.48 V

6 Troubleshooting

6-2 CKA42*7L/5227L

6-3 No Raster

Check the horizontal drive

circuits. (IC401)

Does the drive pulse appear

at Pin 26 of IC401?

Yes

Check Q403 and T401

Does the drive pulse

appear at the collctor of

Q403?

Yes

Check its related circuits

(R414 and C411)

WAVEFORMS

Check flyback pulse at the

collector of Q402 connection of

CN502 and its related circuits

(D403, D409 and T501)

Does the drive output

pulse appear at the base

of Q402?

Yes

4.76 V (IC401, #26)

CH1 P-P = 4.76 V CH1 RMS = 3.652 V

29.4 V (Q403, Collector)

CH1 P-P = 29.4 V CH1 RMS = 13.16 V

10.4 V (Q402, Base)

CH1 P-P = 10.4 V CH1 RMS = 1.384 V

1.104 kV (Q402, Collector)

CH1 P-P= 1.104 kV CH1 RMS = V

+ 4 hidden pages