Hitachi 51F510, Manual

Page: 12 / 152

DP-4X PROT_OVP and PROT_OCP SHUTDOWN DIAGRAM EXPLANATION
PAGE 01-06
PROT_OVP and PROT_OCP SHUTDOWN CIRCUITS EXPLAINED: (A) (B) (E) (F)
(See the PROT_OVP and PROT_OCP Shutdown Diagram for Details).
CPT PROTECT (+200V Excessive Current Detection): One of several Shutdown outputs for (E).
•
On the RED CRT PWB +220V (VM 200V) Excessive Current Detection
Monitored by RE35 . If the 220V draws too much current, the base voltage of QE08 will fall turning it on.
The collector will go high. This high will go to the connector
ERG1
pin
7
labeled as
VM PROT
. This
high continues to the Green CRT PWB connector PSC pin 3 labeled VM PROT on the Green CRT PWB
and CPT PROTECT on the Signal PWB.
•
This line is connected to the PDS3 connector which ties the inputs from the Deflection Side Shutdown
Circuit, identified as (A) 6 inputs active High.
•
Any High from this line is then routed to the PPS1 connector pin 47 identified as (E) . From here this high
is routed to the Signal Power Supply Shutdown Circuit Diagram identified as (E) .
VM GAIN CONTROL (VM 200V Excessive Current Detection): One of several Shutdown outputs for (F).
•
On the BLUE CRT PWB VM+220V Excessive Current Detection
Monitored by REF1 . If the VM220V draws too much current, the base voltage of QEA8 will fall turning
it on.
The collector will go high. This high will go to the connector
EGB1
pin
8
labeled
GAIN CONT
. This
high continues to the Green CRT PWB connector PSC pin 2 labeled VM GAIN .
•
This line is connected to the VM Signal generation circuit and turns it off.
•
This line is also connected to the base of QY60 . This transistor acts as an inverter to change the output
High to a Low on its collector.
•
The collector of QY60 is tied to several circuits. The Voltage Loss Detection Circuits explained below
and the PROT_OCP from the Deflection Side Shutdown Circuit from PDS3 connector pin 9 . Labeled as
PROT_OCP (B) which represents 1 shut down input from the Deflection Side Shutdown circuits.
VOLTAGE LOSS DETECTION CIRCUITS: One of several Shutdown outputs for (F).
•
IV01 generates the SW +2.5V. If this line is shorted or missing, this line will drop Low.
•
IY01 generates the SW +3.3V. DY03 is connected to the SW +3.3V line. If this line is shorted or
missing, the cathode of DY03 goes low which pulls the PROT_OCP line low.
•
IY07 generates the SW +9V. DY04 is connected to the SW +9V line. If this line is shorted or miss-
ing, the cathode of DY04 goes low which pulls the PROT_OCP line low.
•
PROT_OCP: LABELED AS OUTPUT (F).
Any low from this line is then routed to the
PPS1
connector pin
45
identified as
PROT_OCP
(F) . From here this low is routed to the Signal Power Supply Shutdown Circuit Diagram and
again identified as (F) .