Specifications
REV.-A
Second, there are four circuits to protect the supply circuitry and avoid danger. The +5
VDC line
contains a current overload protection circuit and a voltage overload protection circuit. The current
overload protection circuit is part of the + 5
VDC supply circuit. It cuts the + 5 VDC line if the current
is too great. The + 5 V voltage overload protection circuit cuts the supply if the voltage reaches or
exceeds + 7
VDC. It stops the switching circuit operation, which stops the output of the +35 VDC line.
The +35
VDC line has a voltage overload protection circuit and a voltage drop protection circuit. The
+35 V voltage overload protection circuit cuts the supply if the voltage reaches or exceeds +36
VDC.
It stops the switching circuit operation, which stops the output of the +35
VDC line. The voltage drop
protection circuit protects the printer from such damage as might occur from short circuiting in the
secondary circuitry of the +35
VDC line. If a voltage drop is detected, it stops the switching circuit
operation, which stops the output of the +35
VDC line.
Power Supply Board
~
---------------------------- -------------------- -------------------- --
-:
1
1
I
,
1
1
I
Prima ry
~
Secondary
1
b
supply
I
Circuit
+
+5
VDC
1
1
IH.m.m+m
;
,
1
1
1
1
t
1
1
1
1
1
1
I
1
1
1
r
Filter
Circuit
t
I
I
I
I
1
1
1
1
1
1
1
1
1
I
I
I
-------
-------------------------
I
t
AC
Input
t!
1
1
1
1
1
1
*
1
1
1
I
I
1
I
I
1
1
I
1
1
I
1
I
1
1
1
1
+35 line
1
Voltage
1
Drop
1
1
Protection
I
Circuit
1
1
1
1
1
1
1
1
+
VDC
1
1
I
1
1
1
1
1
1
1
1
1
I
1
I
1
1
1
1
-
Power
1
1
t
Switch
1
-----------------------------------
----
J
Figure 2-16. Power Supply Circuit Block Diagram
2-12