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
Month of Issue:
TELEVISION TECHNICAL BULLETIN
Page 1 of 2
SYMPTOM No teletext, poor linearity, no picture, intermittant picture.
Corruption of the NVM, IC1002. Either noise on the five volt supply or corruption of
the data lines normally causes this.
Carry out the following action.
1. Reprogramme NVM location 21 to 5A.
2. Remove L850 from PWB-B ( Video Board ) and fit a wire link from J46 on PWB-B
to wire link J48 on PWB-A ( Mother Board ).
3. Increase the value of C714 to 2,200uF, 16V using the part number below.
4. Fit two 8.2V zener diodes to IC1002 as shown in the diagram below.
5. Fit a 10nF, 50V capacitor between pins 10 and 11 of IC1001, using the part
number given below.
6. Fit a 10nF, 50V capacitor between pin 39 of IC1001 and ground ( link 26 ).
Capacitor 2,200uF, 16V
Zener Diode, 8.2V
Capacitor 10nF, 50V
5 6 7 8
4 3 2 1
Location of the 8.2V Zener diodes Connected to pins 5 and 6 of IC1002 (viewed from the print
side of the Mother PWB)