CTV990503 TELEVISION TECHNICAL BULLETIN
Month of Issue: May 1999 Classification: White Page 1 of 1
MODELS
66AS05H
DV5940H
DV6632H
Common faults on the 4BS-C Chassis
Fault Intermittent tripping Cramping Tripping every five seconds Reason Poor line drive Vertical stage tollerance changes Teletext processor supply pin leaky Possible Cause Q606 C513 open circuit Teletext processor (note that removing the teletext PWB will also result in tripping every five seconds) Dry joints on the scanning coils connections (both ends)
Intermittent failure of the line output transistor
Line stage problems
Disabling of protection circuit To disable the protection circuit, you can remove the opto coupler IC702. However, do be aware that this may cause failure of components if there is a catastrophic fault on the receiver. If you have a fault to add to the above list, please do no hesitate to contact Sharp Technical Support via the Hot Line telephone number.
Sharp Electronics (UK) Limited
Reference AVW280499/3 Revision 1 White � Carry out as required, Yellow � Carry out as required and whenever the unit comes in for service, Red � Carry out on all units
