Block Diagram - NEC DPro2070SB Service Manual

Though DC current is superimposed on the sub yoke, H-STATIC and V-STATIC are pushed to the greatest
possible extent by the adjustment with CP ring in order to reduce the stress of the driver IC8A1 (STK391-
110).
Moreover, although 6H coil is carried in the case of this chassis, in addition to 4H and 4V coils, since the
range which can be adjusted is a range used as fine adjustment, it is a premise that the convergence
between Red, Blue and Green (6H and 6V) is in a standard as a performance of ITC (CRT&DY) in the state
where 6H coil is not used.
As the adjustment procedure, the adjustment values of 30 elements are not respectively zeroed but they
are adjusted to nearest to zero with a total balance in good order.
In other words, the balance (compromise) adjustment with each adjustment item is applied.
The correspondence of the names of DDCC adjustment mode to the coefficients of all 30 elements is
shown below.

1.4.6.4 Block diagram

Fig. 9 shows the block diagram of the DDCC circuit.
The components 4H_DC (pin 6), 4H_SC (pin 61), 4V_DC (pin 8) and 4V_SC (pin 60) supplied from IC601
to 4H-Coil and 4V-Coil are output, the dynamic component (4H_DC, 4V_DC) is amplified with IC6A2, and
the static component (4H_SC, 4V_SC) is amplified with IC6A3.
DDC (pin 7) output from IC601 and DEFL_+3.3V (pin 3) output from IC602 are respectively the reference
voltage of Op-Amp (IC6A2) that amplifies the above dynamic component (4H_DC, 4V_DC) and the
reference voltage of Op-Amp (IC6A3) that amplifies the static component (4H_SC, 4V_SC).
On each of 4H and 4V, the waveform added with the dynamic component and static component is input to
IC8A1 pin 3 and pin 4, and it allows the specified current to flow to each convergence compensation coil.
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