Philips DELLP1230 Service Manual page 84

84 Dell P1230 M25P
9
Go to cover page
F. TDA4856
Check List
1. HFLB
(from H.defl)
3.4.5.6 B+ control
8. HDRV
11.EWDRV
12,13 Vout1/Vout2
14,15
Vsync,Hsync
16. CLBL
Repair Flow Chart
Basic check
Vcc=pin10=12V
Vcc > 9V
gnd =pin7=pin25=0v
during startup
if no exist
a pin3 amplify pin5 and it compare to pin4
b. pin4 generate the saw_tooth wave
c. pin5 input voltage for the square output waveform
d. pin6 pwm output to 7422 & 7423 base
to H_deflection.
7425&7426 base
to B+ control
east/west control
differential input
to 7567 pin 1, 7
the input sync from
7404 pin 14,15
Vertical blank will be activated = hi ,If
1.pin30 = softstart pll2 = 0V
2.pin26 = pll1 is unlock in searching mode
3.pin1 = HFLB no exist
4.pin10 = Vcc < 9V
pin16
CLBL=hi
inhibit pin6 output
if pin3 is pulled to
ground by 7427