Sony D98 chassis Operation Manual page 28

N BOARD SYNC AND CONTROL CIRCUITS
Overview
The N board performs H and V Sync processing within the Microprocessor (IC1001)and DSP (IC1002 Digital Signal
Processor) which generates shaping, centering, deflection drive pulse and other corrections. The DSP is controlled by the
Microprocessor using I2C BUS with the Microprocessor having an external EEP ROM. Other Video functions are controlled
by Microprocessor through the I2C bus.
MICROPROCESSOR
H Sync (sync out from Microprocessor) and V sync (sync out from Microprocessor) is buffered by internal sync processors
and will be sent to DSP and OSD (on A board). In the absence of Video Input, this output will be the Microprocessor's free
running output. The Microprocessor directly outputs the control of H center, H Lin Balance, and Rotation by DAC outputs. In
Accordance with the monitor's operating condition, it switches the Remote On/Off, Heater On/Off, Input select, S Caps, and
Degauss.
DSP (Digital Signal Processor)
This IC requires 3.3v VDD. The 3.3vdc is supplied from IC1006 (Regulator). The DSP outputs waveforms for the deflection
circuit with most of these going to D Board. Pin #1 is V SAW output and will go to D board through IC1007 acting as a
buffer. Pins#6 and #7 are for Dynamic Convergence. Pins #60, 61 are for Static Convergence. Pin #10 is H DF output and
#58 is V DF. Pin #59 is V Key output and #64 is H Shape. Pin #57 is PIN/KEY Bal out, this is supplied to the Phase Lock
Loop(PLL) Circuit of the DSP which is on pin#12 – 22. H Drive Pulse will be outputted from pin#25 after being modulated
by Bal correction and Moire correction(#22). This IC works with 3.3v VDD. The 3.3v is supplied from the IC1006 (Regula-
tor)
Trouble Shooting Hints
See attached "FLOW CHART" to confirm N Board issues.
Incorrect/No Wave form from DSP
Check the 3.3vdc from IC1006, if O.K, confirm that I2C BUS is sending a pulse(0v-5v) to the DSP. Confirm that Reset
(pin#49) is HI and POC-IN(pin#30) is almost 1v.
No Communication or Microprocessor related failure
Check CN1003, CN1004 connections first. If OK, then check 5v supply and to see if X1001 is oscillating, also
RESET(pin#54) is HI. In case of No Communication, confirm pin #38(RXD) is receiving pulse signal (0v-5v).
From A boad
H Sync in
V Sync in
C Sync in
HFDP
KEY SCAN
TXD/RXD
ABL
HVDET
IC1005
EEPROM
IN PUT SW
2
I C BUS
H SYNC OUT
V SYNC OUT
IC1001
MICRO RESET
REMOTE
DEGAUSS
H CENT
HEATER
ROTATION
-S1
H LIN BAL
-S2
-S3
- -
28
C BLANC
3.3V
IC002
DSP
DCC
V SAW
IC1003
2
RESET
IC1007
BUFFER
H SHAP
N board
XSC/YSC
XDC/YDC
HDF/VDF
V Key
HD
5V
IC1006
DSP