Horizontal Deflection And Pincushion Circuits - Sony KV-13FS100 Product & Training Manual

If the drive signals check OK, check the signal output on IC545/pin 3 (Ref. Signal). This signal should appear
as shown in Waveform 4-8. This pulse is used to tell the system control in IC001/pin 78 that the vertical drive is
working properly. Also, confirm that this signal is reaching IC001/pin 78. If this signal is missing or distorted at
IC545/pin 3, then replace IC545.

Horizontal Deflection and Pincushion Circuits

Note: Reference Figure 4-3 during troubleshooting descriptions.
Overview
The subject of this section will be horizontal circuit troubleshooting tips. The Standby/Timer LED may flash in
groups of two or four depending on the type of failure in the horizontal circuit.
Horizontal Deflection Circuit
Horizontal Failure conditions: (reference Figure4-3)
1) Shorted Output transistors (Q505 or Q506): Standby/Timer LED will flash in groups of two. Shorted
Output transistors will cause a shorted B+ line. System Control detects a B+ Over Current condition.
2) Open Output transistors (Q505 or Q506): Standby/Timer LED will flash in groups of four. The Open
Output transistors cause no HD to the FBT; which causes no +/- 13V supply output. In turn, this causes
no vertical drive (IC545) output. System control detects a "No Vertical drive" condition.
3) Excessive Horizontal Output Drive (OVP HV): Standby/Timer LED will flash in groups of four. Because
of the excessive HD, the FBT will be over-driven causing excessive secondary voltages. This includes
High Voltage (HV) and the +/- 13V outputs. FBT/pin 7 is monitored by IC561 for excessive voltage (this
will be discussed in Protection Circuit section). This voltage is proportional to the HV. So, System Control
detects an excessive HV condition.
Oscilloscope
Settings:
10V
5ms
IC545/Pin 3 (Vertical Reference Signal)
Waveform 4-8
18
4. Deflection Circuits