Dynamic Focus Circuit - Sony D98 chassis Operation Manual

Signal tracing should begin at pin 59 of IC1002 on the N board. The triangular output waveform at this point should change
+/-1 vdc by operating V.TrapSawBtm and V.TrapSawTop registers through function through min-max extremes. This same
signal should appear at pin 42 of CN801 and at the input side of R736. Screen movement for this function is as shown below:
1.5mm
1.5mm
V.TRAPTOP
Movement
V.TRAPBTM
Movement
(Dashed lines Indicate
(Dashed lines Indicate
Negative movement)
Negative movement)
Rotation Circuit Troubleshooting Hints
If Rotation does not work Vertical Key will not work. Signal tracing for a rotation problem can start at pin 3 of IC1001. The
Rotation signal will be a square waveform at 40kHz. This signal is filtered at the R729, C705 combination. If this waveform
is reaching R705 the problem is in the IC702 area.

5. Dynamic Focus Circuit

Overview
Both H and V Dynamic Focus Waveform originally formed by DSP.
H DF is amplified by Hi-speed OP Amp and also Transformer.
V DF is amplified by Transistor inverter.
H DF
IC703 is amplifying the H DF waveform formed by DSP. The voltage is re-amplified by T701 to about 600Vp-p and supplied
to FBT.
V DF
V DF waveform is buffered by Q707 and amplified by Q706 to about 200vp-p.
300v Vcc is made by FBT through D906. This voltage is also used for HV Protector.
Troubleshooting
See attached "FLOW CHART" and confirm if it is really a DF issue.
Bad H DF
Confirm that waveform from N board is correctly there(1Vp-p).
Check the voltage of pin#6 of IC703. If no output, change IC703. If there is wave form, change T701.
Bad V DF
Confirm that waveform from N board is around 3Vp-p. If it's more than 3.3Vp-p, change the N board.
Check 300v from FBT.
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