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DP-4X POWER SUPPLY RELAY CONTROL EXPLANATION
See The DP-4X Stand By +5.7V Generation Circuit Explanation for details. (Previous Page)
See The DP-4X Power On and Off Circuit Diagram for details. (Page 01-16)
Power Supply On and Off Circuit Explanation:
The DP-4X Chassis utilizes 5 relays.
1. RY101 AC Supply to the Signal Power Supply Relay
2. RY102 AC Supply to the Deflection Power Supply Relay
3. RY103 DC Supply to the Audio Output Relay
4. RY104 AC Supply to all AC Relays Relay
5. RY105 DC (SW +5.7V) Supply to the Low Voltage Regulators Relay
(4) RY104 AC Supply to all AC Relays Relay
Starting with RY104 because this Relay supplies AC to RY101 and RY102 which in turn
supplies AC to the Bridge Rectifiers for the Signal and Deflection Power Supplies.
When The Stand By Power Supply develops the SBY +5V, (see previous page) this DC
voltage is delivered to the primary windings of RY104 and to the relay driver Q105 for
RY104. This turns on the relay and supplies AC to the above mentioned circuits.
(1) RY101 AC Supply to the Signal Power Supply Relay
When the set is turned on, the POWER SIG command is supplied from pin 59 of the Mi-
croprocessor I004. (This high also turns on the Power LED on the front of the set). This
high is sent to Q018 and Q021 then to the PPS1 connector pin 9 labeled POWER 1.
From here this high goes to the Deflection PWB through R120, R110, D109 to the Base
of Q101 goes high and the transistor turns on. This action supplies a ground return for the
coil inside RY101 and the relay turns on supplying AC to the Signal Power Supply recti-
fier DS201 and the Signal Power Supply begins to operate.
(2) RY102 AC Supply to the Deflection Power Supply Relay
When the set is turned on, the POWER DEF command is supplied from pin 58 of the Mi-
croprocessor I004. (This high also turns on the Power LED on the front of the set). This
high is sent to Q023 and Q024 then to the PPS1 connector pin 11 labeled POWER 3.
From here this high goes to the Deflection PWB through R125, R122, D110 to the Base
of Q102. The base goes high and the transistor turns on. This action supplies a ground re-
turn for the coil inside RY102 and the relay turns on supplying AC to the connector PC2.
Then to the Deflection Power Supply rectifier DP01 and the Deflection Power Supply be-
gins to operate.
(3) RY103 DC Supply to the Audio Output Relay
When the set is turned on, the POWER DM command is supplied from pin 91 of the Mi-
croprocessor I004. This high is sent to Q028 and Q029 then to the PPS1 connector pin 12
labeled POWER 2. From here this high goes to the Deflection PWB through R124 to the
Base of Q103. The Base goes high and the transistor turns on. This action supplies a
ground return for the coil inside RY103 and the relay turns on supplying Audio B+ to the
connector PPS1 pins 1, 2 and 3. Then to the Signal PWB and
on to the Audio Output IC IA02.
Continued on Next Page
PAGE 01-14
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