Rotation Correction Circuit; H Centering Circuit - NEC MultiSync FP1370 Service Manual

The H SIZE MAX has two area of memory (H SIZE MAX 1 and 2) which is selected by the below table.
H Frequency Range[kHz]

6) Rotation Correction Circuit

Raster rotation is corrected by moving the electron beam in the magnetic field produced by current applied
to the Z-coil. The amount of correction is proportional to the current applied to the Z-coil and the correction
can be adjusted with the control voltage (DC) of the D/A converter. The DC voltage output from IC532(D/A
converter) pin 15 generates current to flow in the Z coil, and amount of rotation is determined. User can
adjust the level of rotation by operating OSM menu (Rotate). The level of rotation is controlled by detective
amplifier (IC4J1), and output the current to Z coil by push-pull buffer. (Q4K1, Q4K2)
+5V
IC532
15pin

7) H Centering Circuit

Switching regulator generates the floating 5.5 volts which is compared to the deflection circuit power
supply voltage ( high B+ voltage). This voltage is divided by VR581 (H centering) and is supplied to the
base of Q581. The voltage differences of Q581's base and emitters is supplied to L562.
Horizontal centering is manipulated by the current supplied by L562 to the horizontal deflection circuit.
121.0 – 130.0
111.0 – 121.0
101.0 - 111.0
82.6 - 101.0
69.5 - 82.6
52.7 - 69.5
49.0 - 52.7
41.5 - 49.0
36.6 - 41.5
33.6 - 36.6
30.8 - 33.6
(Fig. 2.10) Rotation Correction Circuit
8-14
Selected Memory
H SIZE MAX 2
H SIZE MAX 2
H SIZE MAX 2
H SIZE MAX 2
H SIZE MAX 2
H SIZE MAX 2
H SIZE MAX 1
H SIZE MAX 1
H SIZE MAX 1
H SIZE MAX 1
H SIZE MAX 2