This machine boot with audio, image and sound public channel of the work. Have a blue background show that final visual circuitry, tube circuit such as normal. No images, no character display, fault should be in the luminance and chrominance signal processing circuit. This machine use IC601 (AN5693K) brightness, chroma and scanning signal processing. As shown. First check IC601 (31), (36) input luminance and chrominance. Find signals are all normal. 4RLservice manual download site
 4RLservice manual download site
Practices, if conditional word, can use oscilloscope waveform of the pin. Without oscillograph, rapid conversion channel television reception methods available for inspection, to use the remote control to choose a local television station signal, then choose an empty channel, monitoring IC601 (31), (36) feet of dc voltage whether there is a slight change, change that has signal input to the IC601. When measured, should choose high impedance multimeter, otherwise, even if there is signal input can also be difficult to observe the change of the voltage. 4RLservice manual download site
 4RLservice manual download site
 4RLservice manual download site
Then measure (15) - (17) feet the R, G, B signals of output voltage, found that the output signal amplitude is small, and pin voltage by normal + 3 V to 1.5 V. Disconnect the mainboard and final visual board asked lead, pin voltage is still low. External bypass capacitors found no leakage check pin (generally three pin voltage decreases, don't have to doubt the bypass capacitor leakage, because it is impossible for general three capacitor leakage), is considered. After IC601 is damaged, replace IC601 troubleshooting.4RLservice manual download site