Adjusting The Electrical Circuits - Sharp VL-WD650U Service Manual

10. ADJUSTING THE ELECTRICAL CIRCUITS

Before starting the electric circuit adjustment
• The adjustment methods described herein are used, in most cases, when the expendable mechanical parts, including
the video head, have been replaced, at which time the electrical circuits need to be readjusted. Before adjusting the
electrical circuits, make sure that the mechanism works properly (i.e., the mechanism is properly adjusted). Incase of
the occurrence of any problem to the electrical circuits, be sure to use the specified measuring instruments to locate
the area to which the problem is occurring, and then take the necessary action, including repair, replacement or
adjustment, exactly as instructed in the electrical adjustment methods that will follow.
Do not attempt to make adjustments without using the proper measuring instruments.
• This machine is configured so that the electrical circuits inside its PWB unit are composed, for the most part, of high-
density, small surface-mounted component parts for downsized machine body.
To perform repair service or parts replacement, do so using a soldering iron, but in as short a time as possible; this is
because surface-mounted component parts are generally so small in size and susceptible to heat, as compared with
the large discrete parts used in TV sets, desk-top video decks, etc., that attempting to heat their electrodes for a longer
time than is necessary with a soldering iron may result in their becoming defective.
This applies particularly when replacing the laminated chip capacitors.
For this purpose, ceramic soldering irons with a temperature regulator are recommended (iron tip temperature 250°C
and soldering time 5 seconds or shorter).
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VL-WD650U