This is the Chapter 16: Television and Video Servicing end chapter exercise in Basic Television – Grob TV as one of the Electronics Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Exam Questions in Electronics Engineering field, Electronics Books, Journals and other Electronics References.
Start Grob TV End Chapter Exercise 16
Answers are Underlined
Television and Video Servicing
- a. An isolation transformer has separate primary and secondary windings. T
- b. The wider blade in a polarized ac line plug connects to the chassis in receivers with a line-operated half wave rectifier. T
- a. DMM has higher resistance as a dc voltmeter.
- b. Meter loading decreases the voltage reading.
- c. The external multiplier for a high-voltage probe is 900 MΩ.
- a. An oscilloscope with a 50 MHz bandwidth must be used for TV servicing. F
- b. The TV switch on an oscilloscope can be set for two cycles of video signal, at either the V or the H scanning rate. T
- c. A dual-beam oscilloscope has a CRT with two electron guns.
- d. A delayed-sweep oscilloscope uses two internal time bases. T
- e. A tuner subber produces the IF output signal. T
- a. The NTSC color-bar generator produces standard chroma and luminance values. T
- b. The color bars in a gated rainbow pattern differ in hue phase by 30°.
- c. Color bars have the standard amplitude of 75 IRE units.
- a. The range of the tint control when it can move a color one bar to the left and right is +/- 30.
- b. Which color-difference signal has the same phase as the burst? (B-Y)
- c. Which color bar has the output from a B-Y demodulator? Sixth
- a. No horizontal output can kill the sound. T
- b. A receiver with current in the ADG coils has AC power input. T.
- a. Two pairs of horizontal bars are produced by 120-Hz ripple in the video signal. T.
- b. Hum in the sync can cause bend in the picture. T.
- a. If the anode potential drops a few kilowatts, the raster will be bigger.
- b. A gassy picture tube can make the anode voltage too low.
- c. Blooming in the picture tube indicates a poor HV regulation.
- d. The grounded clip lead should be connected first in order to discharge the high voltage.
- e. The picture tube shows a thin vertical line before the screen goes black. The trouble is in the Horizontal Oscillator.
- a. Transformer T1 is the horizontal output transformer. T
- b. Conduction in the SCR kills the high voltage. T
- a. An inexpensive way to obtain a good alignment tape is a copy the manufacturer’s original. F
- b. A large error in the scanner rotational speed makes the picture look as if it were out of horizontal sync. T.
- c. Excessive moisture can trigger the automatic stop in a VCR. T.
- a. Ina single-tube color camera, the problem of no color can be paused by poor electrical focus. T.
- b. Balancing red, green and blue for color camera is done by pointing the camera at a stair-step reflectance
- c. Insufficient beam current in a vidicon causes a low-contrast picture. T.
- d. The standard output voltage from a color camera is 1V p-p.