Month of Issue: February 1999
VIDEO TECHNICAL BULLETIN
Page 1 of 2
Sharp Electronics (UK) Limited
White – Carry out as required
Yellow – Carry out as required and whenever the unit comes in for service
Red – Carry out on all units
SYMPTOM Failure of the bias oscillator, leading to permanent erase or loss of the linear audio
track during record and playback.
Due to an increase in the localised heat generated by T651, Q651 can go out of
tolerance. This may lead to Q652 and R658 failing as well.
Carry out the following circuit change.
1. Replace R658 with the same type.
2. Replace C655 with a 47uF, 16V capacitor.
3. Replace L651 with the one listed below.
4. Replace Q652. If the PWB is damaged so that this component can not be fitted,
follow the instructions on page 2 to fit a radical component.
5. Replace Q651 where necessary and bending it away from the transformer, as
shown in the diagram below.
Figure 1: Correct Positioning of Q651
Push Q651 away
from T651 as
Q651 connections (as viewed
from the base of the device)