Table of Contents
Advertisement
DEFLECTION
TROUBLESHOOTING
(Deflection and High Voltage Drive Signals)
20.w
10 .cJ#/
/p-p = 10.68 v
The deflection circuit in the DP-85 chassis operates
4755 functions as an Emit-
differently from previous chassis. This chassis utilizes
ter follower and produces
the Horizontal Blanking
signal from it's Emitter.
a dual horizontal section One
for High voltage and one for de-
flection. The High voltage sec-
tion will not operate without the
deflection section operating.
The deflection section receives
it's drive waveform from 1702
on the sub deflection PWB. The
Drive signal can be checked on
PDDl connector at Pin 7.
1 .oov
10
.og/
vp-p = 3.281 v
1
Freq = 33.70kHz
DC Volts = 1.79Vdc
4755
Emitter
Also
H.Blk
7
Frcq = 33.73kHz
?C Voltage = 1.77Vdo
-!--I-!
L
j~~~~~~~~~-
DC voltage = -26.5Vdc gence section. The nega-
PDDl
Pin 7 (H. Drive)
This drive waveform is made avail-
able to the base of 475 1. The sig-
nal off the collector of Q75 1 is
routed to the Drive transformer
is routed to the Conver-
T75 1, which in turn supplies a sig-
gence output Transistors and is either sent directly into
nal to the base of the Deflection
the IC or rectified outside the IC to become -33V.
, .
:51
Base Li Horizontal Output Q777.
Likewise, the 28Volt
2
00"
Vp:p = 6.605
V
10
.-s/
Freq = 33.73kHz
DC
Vol t age
= 265Vdc
T752
Pin 11
power supply 1s proc-
e
ssed the same way.
r
1o.w
10
.bd
Vp-p = 12.34 V
4
Freq = 33.78kHz
DC
Vol t age
= -0OlVdc
Investigate
these wave-
forms care-
fully.
DC 22.3Vdc
li,
Q75 1 ColIector
9
l-752
Pin I
Deflection
H. Pulse
I I
I
The Deflection H. Pulse is
10
Freq = 33.7BkHz
produced from T752 pin 7.
DC Voltage = O.DVdr;
This signal is used to de-
tect for proper operation of
the Deflection circuit
through 4754 and Dy-
namic Focus by DF02,
QF02 through QF09.
The output from the Col-
lector of 4777 and/or
Pin 1 of T752 is routed
to IHOl pin I. This IC is
responsible for Wave-
shaping and delaying the
signal to be utilized by
the High Voltage Sec-
l.COJ
l".uy/
IHO 1
Pin 1
Vpmp = 4.437 v
Freq =
33.76
kHz
DC Voltage = 1.36Vdc
11
4777
Base
2oov
lO.og/
vp-p
= 1.174 kV
Freq
= 33-70
kHz
DC=
129.5Vdc
w
When the deflection circuit fires
up, it produces drive for the
Horizontal Deflection Yokes, as
well as several other different
signals.
Q777 Collector,
And T752 Pin 1
1
tion.
One of the Waveforms pro-
duced is Horizontal Blank-
ing. This is created by 4755.
The signal off the Collector
of 4777 and/or Pin 1 of
T752 is routed to the Base of
Q755.
After entering the IC, it
is output at Pin 4
1 .c#"
.
,
vp"p = 4.437 v
Freq = 33.78 kHz
DC Voltage = 1.65Vdc
20 ov
vp-p =
12.97 v
. /
Freq = 33.73kHz
6
DC Voltage
= 1.26Vdc
l---A
PAGE 02-I 0
Advertisement
Table of Contents
