TOSHIBA SDV290
Service Manual

3. SERVO CIRCUIT (1) Unstable Video in PB MODE
Unstable Video in PB Mode. YES Does the Noise level of the screen change periodically? YES Do the CTL pulses appear at the IC501 Pin97? YES Does the CFG waveform appear at the IC501 Pin87? YES On tracking do the CTL pulses move? YES Does the Video Envelope waveform appear at the IC501 Pin9? YES Replace the IC501. NO Refer to �When the Y signal doesn�t appear on the screen in PB Mode�. NO Replace the IC501. NO Is adjusting the height of the CTL Head accurate? NO Readjust the height of the CTL Head.

Refer to �(2) No 12VA of Power section� Do the Drum PWM Pulses appear at the IC501 Pin76? YES Aren�t the foil patterns and the Components between IC501 Pin76 and PMC01 Pin12 short? NO Do the DFG Pulses appear at the IC501 Pin90? NO YES Do the Drum PWM Pulses appear at the IC501 Pin76? YES NO Replace the IC501. Aren�t the foil patterns and the Components between IC501 Pin 90 and PMC01 Pin11 short? NO YES Do the DFG Pulses appear at the PMC01 Pin11? NO Replace the Cap M.

(2) When the Drum Motor (2) doesn�t run.
When the Drum Motor doesn�t run,

Does 12V appear at the PMC01 Pin8? YES Does 2.8V appear at the PMC01 Pin12? YES Check the connector (PMC01) and the Drum Motor Ass�y.

NO

Aren�t the connecting patterns and the Components between IC501 Pin76 and PMC01 Pin12 short? 3-8