State the functions of the following instruments in fault finding – NABTEB QUESTION

(i) Colour generator

1. Used for convergence adjustments for colour picture tube.
2. Used for checking convergence error.
3. Used for checking linearity of the vertical and horizontal scanning.
4. It provides signals for (i) small, white dots in horizontal rows and vertical columns. (ii) a cross hatch pattern of horizontal and vertical white lines. (iii) ten vertical colour bars.
5. It produces a single dot or cross at the exact centre of the picture.
6. Useful in locating the mid screen area for beam landing adjustment.

(ii) Pattern generator

1. It provides video signals and use for the alignment, testing and servicing of TV receivers.
2. The output signal produces patterns (vertical and horizontal bars, chequer – board, cross – hatch, dots e.tc.) that are used for linearity and video amplifier adjustments.
3. It provides FM sound signal used for aligning sound section of the receiver.

(iii) Multi meter

1. Used to get information about the symptoms of a particular fault such as short circuit and open circuit at which a set of voltage readings at critical points in the circuit must be taken. Also, current flowing through a point and the resistance between two points can be measured by multi meter to know the particular fault.

(iv) Soldering iron

This is an electrical device used in heating a junction to which solder is being applied. It is also used to melt a soldered joint in order to remove the soldered component.

(v) TV Analyzer

1. Used for trouble shooting faults in the receiver
2. It provides all the outputs and essential signals of the television signals in form of patterns.