View Sharp 28HW-53 (serv.man17) Technical Bulletin online
When fault finding in the east/west circuit, it is important to ascertain in which part of the circuit the fault lies. Check the
control output of IC801 – pin 32. There should be a parabola waveform on this pin at a base frequency of 50Hz. It will
change wave shape depending upon the amount of correction applied, so it is important to enter the service mode and
ensure that none of the adjustments are at minimum or maximum.
Faults in this area include:
3. D603 and D604 going open or short-circuit.
4. Dry joint on C601 and/or C610.
by the memory IC – IC1003 or the VDP - IC801. It is recommended that if this is the case, then the NVM is blanked or
reflashed first. If this does not cure the problem, then it is probable that IC801 is at fault.
necessary to ensure that the EPROM (IC1002) is correct (see CTV2001 05 04). When the correct EPROM is fitted, the
NVM will have to be blanked to enable the correct information to be downloaded into it. Replacement EPROM’s have
been produced so that minimal geometry adjustments are required. If the picture geometry is very poor after following
the above procedure, the fault will be elsewhere in the east/west circuitry.
RCILP0262BMZZ and L602 - RCILP0294BMZZ.