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DP-4X PROT_OVP and PROT_OCP SHUTDOWN DIAGRAM EXPLANATION
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).
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