HEATH
.7'11"6
TRI-POWER SUPPLY
Model SP-2718
595-1841-02
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Copyright © 1976
Heath Company
All Rights Re.
served
BENTON
HEATH
HARBOR,
COMPANY
MICHIGAN
49022
Page 2
TABLE OF CONTENTS
SPECIFICATIONS ..
OPERATION
CONTROL AND SWITCH FUNCTIONS
OPERATING PROCEDURES .
APPLICATIONS..
Independent Mode Applications . . . . . . . . . . . . . . . . . . . . . . 7
Tracking Mode Applications . . .
IN
CASE
General ... . . ...
Troubleshooting Chart
..
OF
DIFFICULTY
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...
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...
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..
... . .. . ........
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.. ... ... ..
.
..
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......
...
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. . 9
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5
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. 6
7
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10
10
CIRCUIT DESCRIPTION
Primary Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-Volt
Supply.
20-Volt 'A' and 'B' Supplies
Metering Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15
CALIBRATION
APPENDIX
Parts List
Circuit Board X-Ray View . . . . . . .
Schematic Diagram . .
WARRANTY .
SERVICE INFORMATION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
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. .
. . . ... . . . Inside front cover
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. . . " Inside rear cover
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. (Fold-in Page)
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. . 20
14
14
14
15
.16
18
18
SPECIFICATIONS
Page 3
Outputs . .
'A' -Supply
'8'
-Supply
Regulation
Load .. .
Line
..
Ripple
................ . , ... , ... . .
..
.. . . . ... . . ............ . . ... . . ....
.. ..
. . . . . . . . . . ...........
.....
. . . .
...
. . ...
...
. . . . . . . . .
. . . . . ....
and
....
Noise . ... .
. . .
...
" .
.............
.......
...
. ,
....
. . .
........
..
. . . . . . .
' " . . " . , .
. . .
......
. .
. .
. . .
5 volts
DC
::!::
5%
at 1.5 ampere.
0-20 volts
continuously adj,ustable.
.
0-20 volts
continuously adjustable.
Less than 0.1 % (20 mV) variation
from no load to full load
on
Less than
from no load
on
20-volt Supplies: Less than
0.2%
voltage change
5-volt Supply: Less than
0.2% (10
voltage change of 10 volts.
Less than 5 mV rms.
DC
at 0.5 ampere,
DC
at 0.5 ampere,
20-volt supplies.
3%
(150 mV) variation
to
full load
5-volt supply.
(40
mV) for a line
of
mV)
for a line
10 volts.
..
Current Limiting
Tracking Range
Tracking Error
Series Operation
Parallel Operation . .
VOltage-Current Monitor Accuracy .
. . ...... . . .
........ . . ....
..
. . . . . . . . . . . .
......
..
. . . ...... . .... ....
..
...
...
. . . . . . . ...
........
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....
....
. . . .
. . ... . . .
.. ..
.. ..
. . . . .
. .
..
...
. . . . . .
......
....
.. . . .
... . ...
.. . . .
. .
. . .
...
Limiting for each supply
fixed
slightly above rated current
to
provide short-circuit protection.
2 to 18 volts.
Less than 1 volt.
All three supplies may be
in
connected
20-volt supplies may be operated
.
in
parallel by adding 0.
current-equalizing resistors (not supplied).
of
5%
.
series.
511
full scale.
Page 4
Meter Ranges . . .
Power Requirements
Power Switching Overshoot (On-Off)
Voltage Control, 20-Volt Supplies A and B .
Dimensions .
Weight
............
... . .... . ..
..
.. ..
. .
.. ............
. . ... .
The Heath Company reserves the right to discontinue products and to change specifications
at any time without incurring any obligation
sold.
...
...
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...
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.............
. . . .
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..
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. . . . .
Voltages, 0-20 and 0-5.5.
Current, 0-550 mA and 0-2A.
.
100-135 VAC or 200-270 VAC,
50/60 Hz, 100 watts at full load.
None.
Continuously variable,
oto 20 volts.
4-1/2" high x 10-3/4" wide x
cm
(11.43
10 Ibs
.
x 27.3
(3
.73 kg).
-
to
incorporate new features
cm
x 22 .86 cm).
9"
deep
in
products previously
OPERATION
Refer
Before you use your Tri-Power Supply, you should become
entirely familiar with its capabilities, characteristics, and its
features. Study Figure 1 to learn each control and switch
function as you read this portion of the Manual.
to
Figure 1
(on
the fold-in).
Page 5
CONTROL
AN,o
LINE AND POWER SWITCHES (SW2 and SW1)
Line switch SW2 is located on the underside of the chassis. If
the line voltage
driver tip
slide. If the line voltage
the switch slide
The POWER switch
that applies the line voltage to the primary circuit
transformer when you push the switch to the ON position.
the same time, power
power has been applied to the unit.
in
your area
to
push the switch slide to expose the
to
expose the "240."
is
100-135 volts AC, use a screw-
in
your area
on
the front panel is a simple slide switch
is
applied to the pilot light to indicate that
is
200-270 volts AC, push
"120"
of
the power
on
the
At
METER SWITCH (SW4)
It
is
important that you know that METER switch (SW4) does
not switch any output voltage or current. The switch permits
you
to
observe any of the Power Supply outputs on the meter,
whether voltage or current. The METER switch thus allows
to
you to monitor any of the variable outputs and
accurately
to
any desired levels.
set them
METER
Note that the meter scales are printed
scale,
in
red, corresponds to each of the METEr! switch functions that also are lettered
a load from the output of the A supply; uB-AMPS" (current
flowing to a load from the output of the B supply; and,
5V-VOL TS (the voltage available at the output of the 5-volt
supp.ly).
The
l:Jpper
meter scale,
METER switch functions, also printed in black:
in
red: "A-AMPS" (current flowing to
in
black, corresponds to the following
in
two colors. The lower
"A
-VOLTS"
SWITCH FUNCTIONS
(the voltage at the output of the A supply); "B-VOL TS" (the
voltage at the output of the B supply); and, "5V-AMPS" (current flowing to a load from the output of the 5-volt supply) .
SUPPL Y A CONTROL (R7)
When you turn this control clockwise from its
output of front panel jacks J4 and J5 (OUTPUT A) will increase
from zero to any level up
500 milliamperes. Read these levels on the meter when the
METER switch is either at "A-VOLTS" or at "A-AMPS."
NOTE:
In
the TRACKING mode of operation, Supply A control
R7
is
disabled; control of the 20-volt A-supply is transferred to
• A TRACKING B.control
side of the front panel, which operates
with
0 SUPPLY B control R9).
to
20 volts and a load current up to
RS
(the small red knob at the right
"0"
as
a clutched control
o SUPPLY B CONTROL (R9)
Control
panel. The other half of this control
knob and is labeled
the two control knobs. The two controls are "clutched" together
knob is turned. Note that black knob
black letters
control.
J6 and J7. This control will vary the available B-supply voltage
peres. Read the output levels on the meter when the METER
switch is turned to B-VOL TS and to B-AMPS.
R9
in
Control
from zero
R9
is
half of the dual control at the right side of the front
is
turned with the small red
".
A TRACKING
such a manner that both controls will turn when either
("0
SUPPLY B")
adjusts the amount of voltage at OUTPUT B jacks
to
20 volts DC and a load current up to 500 milliam-
B"
in
red lettering above
R9
corresponds
on
the panel just above the
position, the
to
the
Page 6
• A TRACKING B CONTROL (RS)
Control
time either control is turned, the other will turn with it. Since it
a friction action, either control may be operated independently
of the other, providing the other control
RS
ING position.
SUPPLY A control R7, and is controlled by the small red knob
at
A and B 20-volt power supplies connected together internally.
RS
is "clutched" to
is enabled only when MODE switch SW3
In
this manner, the A 20-volt supply is disabled at
RS.
At no time are the electrical and electronic circuits of the
"0
SUPPLY
B"
control A9. At any
is
held
in
place. Control
is
in the TRACK-
is
MODE SWITCH (SW3)
In
the INDEPENDENT mode of operation, the 20-volt A supply
is connected
the Mode switch.
control
When MODE switch SW3
to
SUPPLY A control
In
this mode, the A-supply
R9
(small red knob) is disconnected from the circuit.
is
R7
through the contacts of
is
"floating" and
in
the TRACKING mode, control
A7 is removed from the circuit, and contro'l A9 is enabled and
the A-supply will track with the B-supply through the clutch
action of the dual control knobs.
OUTPUT JACKS (J1-J7)
Output jack
you wish to reference any of the three supplies to ground,
external connections from the appropriate supply jacks may
be connected to J 1 .
Jacks J2 and J3 are the connections for the fixed 5-volt,
1.5-ampere power supply.
Jacks J4 and J5 are the connections for the variable 20-volt,
500 milliampere A power supply.
Jacks J6 and J7 are the connections for the variable 20-volt,
500 milliampere B power supply.
J1
is a chassis ground connection. If, at any time,
OPERATING PROCEDURES
Two modes of operation are provided at the output jacks on
the front panel. These are the "Independent" and the "Tracking" modes. Each will be discussed under separate headings.
INDEPENDENT MODE
Each of the three power supplies
be operated independently from one another, either floating or
referenced to another AC or DC source, or referenced to the
Tri-Power Supply ground connection at J1. In addition, any of
the separate supplies may be connected
nal jumpers to provide up to 45 volts DC, referenced to any
external or internal level. NOTE: External references may not
exceed 200 volts.
TRACKING MODE
In
the TRACKING mode of operation, the 20-volt A and B
supplies are clutched together at the front panel dual control
RS/R9.
As either of the controls is turned, the other will turn
in
the Tri-Power supply may
in
series with exter-
the same manner. To adjust the controls, the voltage output
must be observed on the meter for each 20-volt supply, and
AS
the level of each set by controls
wish to have the A-supply referenced 5
variable B-supply, you should proceed as follows : Turn dual
R9
controls R8 and
R9
knob at
until A-VOLTS on the meter indicates
red knob. As you turn the black knob, the A-supply voltage will
track the B-supply voltage, always at a potential of 5 volts
(:t5%)
In
the TRACKING mode, the A and B supplies may be operated
referenced internally with jumpers, or to an external reference
voltage not exceeding 200 volts. As
mode, the three supplies may be connected as any combina-
in
tion
reference.
and hold
higher than produced by the B-supply.
in
parallel as a tracking pair of output voltages, either
in
series, to supply
fully counterclockwise. Grasp the black
it
as you turn the small red knob on R8
up
and R9. For example, if you
vo.lts
greater than the
+5
volts. Release the
in
the INDEPENDENT
to 45 volts total at any desired
APPLICATIONS
Page 7
The Tri-Power Supply is an ideal instrument for experimenters
and engineers. As an example, at Heath Company an engineer developed a transistorized preamplifier circuit for which
he needed supply voltages of - 16 volts DC and
in order to check out the circuit. Using the Tri-Power Supply, he
connected A
output. He then connected a jumper from the chassis GND
reference to the common connection between the two
supplies.
volts and the B-supply output produced +16 volts.
+ to
B-,
and set the A and B supplies
In
this manner, the A-supply output produced a
+16 volts DC
to
16 volts
-16
INDEPENDENT MODE APPLICATIONS
INDEPENDENT FLOATING SUPPLIES
Refer to Figure 2
Figure 2 illustrates each of the three Power Supply outputs
connected
floated at a level up to 200 volts from ground, or from each
other.
In
this example, the MODE switch is at INDEPENDENT;
SUPPLY A control
circuit, and SUPPLY B (black) control
the other 0-20 volt circuit.
Each of the supplies has fixed current Hmiting in all modes of
operation at slightly above the rated current output. This provides infinite short-circuit protection to the Power Supply.
as
you read the following information .
to
separate loads. Each of the supplies may be
R7
controls the output level of one 0-20 volt
R9
controls the output of
The following sections of the Manual will show you a number of
examples of how you can use your Power Supply. The variety
of uses
NOTE: Since 5 volts is used extensively
applications, it is incorporated into the Tri-Power Supply as a
fixed output. This 5 volts DC may be referenced to any other
voltage
GND jack at J1.
@m
is
extensive, however, so only a few are given.
in
TTL logic
up
' to 200 volts,
or
to the Power Supply front panel
+oDbIQvQmQ+
I I I I I I
I I I I I I
I I I I I I
I I I I I I
I I I I I I
I I I I I I
I I I I I I
II I I I I
1
~
~
:
LOAD
0-500mA.
I
LOAD
0-500mA .
~
.011LF
NOTE: Each circuit output has a
from
,it
s negative terminal
capacitance on the load circuit should be considered when
you attempt to float any of the supplies at a level above chassis
ground.
to
chassis ground. T
capacitor connected
he
effect of this
Figure 2
Page 8
INDEPENDENT
GROUND-REFERENCED SUPPLIES
Any of the output terminals, whether + or
to
nected
lists many of the possible voltage combinations using chassis
ground as a reference.
ground, and
I 5 Volt Supply
in
any combination. The following chart
A-Supply
-,
I
may be con-
B-Supply
+ 5 volts, fixed
+ 5 volts, fixed
+5
volts, fixed
+ 5 volts, fixed
-5
volts, fixed
-5
volts, fixed oto + 20 volts
-5
volts, fixed oto - 20 volts
-5
volts, fixed oto - 20 volts oto - 20 volts
oto + 20 volts
o
to
+ 20 volts
o
to
- 20 volts oto + 20 volts
oto - 20 volts oto - 20 volts
oto + 20 volts
.
I
LOA
I 0 -
D
I.SA.
LOA
D
O-SOOmA
oto + 20 volts
o
oto + 20 volts
oto - 20 volts
oto + 20 volts
---
.
to
- 20 volts
LOAD
D-
SOOmA.
Figure 3
.---~
r-Io--
O-
LOA
D
SODmA.
r---~
....
Figure 4
Figure 4
the circuit are connected
the high end of the circuit. Thus the output to the load
variable from - 5
mA
if
is
an example of a circuit
in
series, with a ground reference at
to
-45
volts. Load current is limited to 500
by the A and B-supply limiters.
~Bt¥l~m<r?,'
----I
1 1 I 1 I I
1 I 1 I 1 1
I 1 I I 1 1
1 1 1 1 1 1
1 1 1 1 I 1
1
1
0-1.
I 1 1 1 1
I
I
LOA
D
SA
.
in
which the three outputs of
I I I 1
lit!
LOA
D
O-SOOmA.
LOA
0-500mA.
is
D
Figure 3 illustrates an example of a circuit
terminal
and B supplies are referenced to
positive-going 20-volt supplies can be varied from
volts
is
referenced
(+20
volts, overall).
to
ground, and both the 0
-5
in
which the + 5 volt
volts. Thus, each of the
to
+ 20-volt A
-5
to
+ 15
Figure 5
Figure 5 illustrates the Tri-Power Supply connected
separate outputs of + 5 volts, fixed, the A-supply variable from
oto
+20
volts, and the B-supply variable from 0 to
to
produce
-20
volts.
TRACKING MODE APPLICATIONS
Page 9
r-
SV . 1.
@m
~omOI~m?~!m@+
SA
n
I I I I
I I I
I I I I
i :
I : :
I I
..
0-20V •.SA
so
fo
.
",
,--..,.--~
-'I
I (
NOT
~~
~~
Figure 6
NOTE:
In
the Tracking Mode of operation,
scribed, A-supply control is clutched to the B-supply control at
R8/R9.
PARALLEL OPERATION
The purpose of connecting the two 20-volt power supplies in
is
parallel
shows a typical Power Supply-to-Ioad connection in which up
to 1 ampere of current is available to the load. Note that 0.5
ohm current-sharing resistors (not supplied) are used in the
output connections. The output voltage of the circuit is reduced by the
tors. Each supply is short-circuit and overload protected;
either 20-volt supply may current-limit slightly before the other.
to provide higher current through the load . Figure 6
IR
voltage drop across these equalizing resis--
as
previously de-
~%
5 U P P L I [D )
TRACKING-FLOATING CIRCUITS
NOTE: Each of the three power supplies is connected to a
7.
separate load as shown in Figure
and independent of reference levels.
MODE switch must be in TRACKING to produce the following
outputs: 5 volts fixed and floating, B-supply 0 to
floating with the A-supply output floating,
at
supply
tracking
Bany manner of series connections of
the Tracking mode.
@m
any predetermined voltage differential. To create a
:t
supply, the
terminal, for example. The Power Supply may be wired
A+
terminal may be connected to the
~Q.EQIQV~~
r I I I I I
I I I I I I
I I I I I I
I
I I I I I
I I I I I
I I I I I
I I I I I I
~
~
Figure 7
Each supply is floating,
In
this configuration, the
and
tracking the B
A,
B,
and 5-volt outputs in
II
:
LOAD:
O-SOOmA
.
+20
I I
;
LOAD
O-SOOmA
volts
in
1
.
Page 10
IN
This part of
difficulty which might occur in your Power Supply. The infor-
mation is divided into two sections. The first section, "Gen-
eral," contains suggestions of a general nature in the following
areas :
CASE OF DIFFICULTY
the
Manual will help you locate and correct any
A. Bench-testing precautions.
B. Repair techniques.
GENERAL
BENCH TESTING
WARNING: The full
present at several points
avoid personal shock when you work
Refer to Figure 8.
Be
•
•
cautious when you test the transistors and integrated
circuit. Although they have almost unlimited life when
used properly, they are more susceptible to damage
from excessive voltage and current than other circuit
components.
Do
not short any terminals to ground when you make
voltage measurements. If the probe should slip, for
example, and short out a bias or voltage supply point, it
may damage one or more components.
AC
line voltage and high voltage
in
the Power Supply.
on
the Power Supply.
Be
DC
careful
to
The second section consists of a "Troubleshooting Chart." It
calls out specific problems that may occur and lists one or
more conditions or components that could cause each difficulty. Capacitor C-numbers, transistor Q-numbers, etc., are
in
identified
the Schematic diagram. A "Circuit Board X-Ray View"
Page 20) is also provided
NOTE:
difficulty, refer to "Customer Service" information inside the
rear cover of the Manual. Your Warranty is located inside the
front cover.
•
is
•
•
•
this chart by the same numbers that are used
to
help you locate the components.
In
an extreme case where you are unable to resolve a
Do not remove any components while the Power Supply
is
line cord
When you make repairs to the Power Supply, make sure
you eliminate the cause as
trouble.
resistor,
become damaged. If the cause is not eliminated, the
replacement resistor may also become damaged when
the Power Supply is put back into operation.
Refer
"Schematic" to locate the various components .
Use a high impedance-input voltmeter
voltage measurements.
connected to the
If,
for example,
be
sure you find out what caused the resistor to
to
the X-Ray View
AC
outlet.
well.
as the effect of the
you
should find a damaged
on
Page
20
and the
to
make any
on
(on
Page
11
..
_----
Figure 8
REPAIR TECHNIQUES
Components
Faulty resistors or capacitors should first be clipped from component leads from the circuit board, heat the solder on the
and allow the lead to fall out of the hole. Preshape the leads of
the replacement part and insert them into the holes
circuit board. Solder the leads to the foil and cut off the excess
lead lengths.
Transistors can
described. The replacement transistor must be installed with
its leads
avoid heat damage. Cut off the excess lead lengths.
be
removed
in
the proper holes. Then quickly solder the leads to
in
the same manner as previously
in
foil-
the
CAUTION: On several areas of the circuit boards, the foil
patterns are quite narrow. When you unsolder a part for check-
ing or replacement, avoid excessive heat while removing the
part. A suction-type desoldering tool will make part removal
easier.
Foil Repair
A break
across the break. Large gaps in the foil should be bridged with
a length of bare wire. Lay the wire across the gap and solder
each end
in
a circuit board foil can be bridged by soldering
to
the foil.
Page
12
TROUBLESHOOTING CHART
GENERAL
CONDITION
Power Supply completely
inoperative.
Fuse blows.
5-VOLT SUPPLY
No Output
Output greater than
5.25 volts
Unable to get 1.5 amperes
of current from supply.
Excessive ripple
output jacks.
5-volt supply not floating.
Resistance from either
output jack
is less than 1
I
DC.
to
at
chassis
Mil.
POSSIBLE CAUSE
1.
Fuse blown.
2. Power switch
3.
Line switch SW2.
1.
Integrated circuit IC1.
2.
Capacitors
C10B or C20B faulty.
1.
Diodes
2.
Resistor R4.
3.
Integrated circuit IC1.
1.
Integrated circuit IC1.
01
C2,
or 02.
Ii
1.
Integrated circuit
defective.
2.
Resistor R4.
1.
Integrated circuit
2.
Diodes
3.
Capacitor C2.
1. Integrated circuit
case contacting chassis.
2.
Capacitor
01
or 02.
C5.
SW1.
C103, C203,
IC1
IC1
.
IC1
20-VOLT A OR B SUPPLIES
NOTE: Since both of the 20-volt supplies are identical, troubleshooting for both supplies is the same. If one of the 20-volt
supplies operates correctly, you may be able to compare
in-circuit voltages to identify a problem. All 1
are
in
nents
B-supply.
I
No
supply.
,
the A-supply; all200-series components are
CONDITION
output from 20-volt
1.
2.
3. Transistors 0101, 0102,
4.
5. Zener diodes ZD104,
6.
I
POSSIBLE CAUSE
Diodes
diodes 0201, 0202, 0203
open.
Resistors R101,
or resistors
R209 open.
0107,
0103,
0202, 0203
0201,
open.
Capacitors C102, C109, or
capacitors C202, C209
shorted.
ZD109, or zener diodes
ZD204,
Transistors 0104, 0105,
0106, 010B, or transistors
0204,0205,0206,020B
shorted.
OO-series
0101,0102,0103,
R201
or transistors
ZD20B, ZD209 shorted .
compo-
R103,
, R203,
, or
ZD10B,
in
R109,
0207
the
or
Page
13
I
CONDITION
too
Output
be
adjusted.
Output current too low.
high, cannot
POSSIBLE CAUSE
1.
Transistors
0102
, 0103,
01 , 0107, or transistors
0202, 0203,02,0207
shorted.
2.
Diodes 0105, 0110, or diodes
0205, 0210 open.
3.
Zener diodes
or zener diodes ZD208,
ZD209 open.
4.
Transistors
transistors 0206,
open.
1.
Resistor R109 or
resistor R209 open.
2. Transistor
0204
sistor
ZD1
0106
0104
faulty.
08,
, 0 1
08,
0208
or tran-
ZD109,
or
CONDITION
Output current does not
limit.
I
to
chassis
Mil.
in
Excessive ripple
output voltages. 0201 , 0202 open or faulty.
Supply not floating.
Resistance from either
output jack
is less than 1
1
POSSIBLE CAUSE
1. Solder bridge A or solder
bridge B open.
2.
Transistor
sistor
3.
Resistors R108, R109 or
resistors R208, R209
defective.
1.
Diodes 0101, 0102 or diodes
2.
Capacitors C101, C103, C104,
C105, C108 or capacitors
C201, C203, C204, C205,
C208 open or faulty.
1.
Transistor
02
2.
Capacitor C6 or capacitor
C7
0104
0204
faulty.
01
or transistor
case shorted
faulty.
or tran-
to
chassiS.
Page
14
CIRCUIT DESCRIPTION
Refer to the Schematic Diagram while you read this "Circuit
on
Description." The part numbers
ranged in the following groups to help you locate specific parts
on
the Schematic, chassis, and circuit boards:
99
1-
101-199 Parts mounted
201-299 Parts mounted
Parts mounted
20-volt 'A' Supply.
20-volt
'8
' Supply.
on
on
on
the Schematic are ar-
the chassis.
the circuit board, and
the circuit board, and
in
in
the
the
PRIMARY CIRCUIT
The primary circuit of the Tri-Power Supply includes hash-filter
C1
capacitor
SW1, pilot lamp PL 1 and dropping resistor
SW2. The purpose of the Line switch is to allow you to switch
from 120-VAC operation to 240-VAC operation without rewiring the primary circuit of power transformer
from 120-VAC operation to 240-VAC operation, for example,
you need only to push the slide of switch SW2 to indicate the
voltage that agrees with the local AC service.
across the line cord input, fuse
F1
, Power switch
R1
, and Line switch
T1
. To change
The five principal sections of the Tn-Power Supply are the
power primary circuit, the 5-volt supply, the 20-volt 'A' Supply,
'.s'
the 20-volt
Three transformer secondary windings provide separate voltage sources for the three voltage regulators of the 5-volt
supply and the two 20-volt supplies.
Supply, and the metering circuit.
One secondary winding on transformer
D1
and
02.
to rectifier diodes
filtered by capacitor C2. Resistor
metering circuit.
in
Regulation
circuit
the 5-volt circuit is accomplished
IC1
. The output voltage is fixed at 5 volts. The
The rectified
R4
is a current shunt for the
5-VOLT SUPPLY
T1
provides a voltage
DC
voltage is
in
integrated
provides internal overload, short-circuit, and high temperature
protection. Capacitor
capacitor C4 lowers the high-frequency output impedance.
Capacitor C5 provides
ages induced when the 5-volt supply is used
mode of operation.
IC
C3 stabilizes the IC-regulator, and
an
AC
path to chassis ground for volt-
in
the floating
Page 15
20-VOL T 'A' AND
NOTE:
In
the description of the 20-volt supplies, the
"8"
circuits are identical. One circuit will be described
text which applies to either supply. Component callouts
C111,
0103,
etc.)
in
the 100-series are
ponent call outs in the 200-series are in the 8-supply.
in
the A-supply; com-
RECTIFIER-FILTER CIRCUIT
One transformer secondary winding provides
full-wave rectifier diodes 0101 and 0102. The rectified voltage
is routed through blocking diode
capacitor C103. Resistor R103 is a bleeder resistor to discharge C103 when the Power Supply is turned off.
A negative
and 0107. This voltage
then routed to the voltage regulator.
voltage is derived through rectifier diodes 0106
is
filtered by capacitor C105, and
0103
an
and is filtered by
CURRENT SOURCE
Current flows from the positive side of capacitor C 1 03, through
zener diode
The voltage drop across R104 is fixed at a constant value by
ZD104 and the constant base-to-emitter voltage of transistor
0102. Thus, the current through R104 is constant. Since the
collector current of
current, the collector current will also be constant.
Transistor 0101 acts
power supply is turned on. However, 0101 turn-off
by the action of capacitor
output
ZD1
04, through resistor
0102
is very nearly equal to its emitter
as
a switch, to turn
C101
of
the supply when power is switched off.
R1
03, to transistor 01
on
to eliminate transients
quickly when the
"A"
and
in
this
(R1
01,
AC voltage to
is
01
is
delayed
on
the
'8'
SUPPLIES
VOLTAGE REGULATOR
The reference voltage for the regulator circuit is derived from
zener diode
resistor R115 and zener diode ZD10B . ZD10B and resistor
R106 are a pre-regulator for the reference source.
Differential transistors
the reference voltage
output voltage sampled between resistors R123 and R124.
An example of the action of this regulator circuit might be
follows : If the output voltage rises due to a reduction
load, the base voltage of transistor
collector voltage of 01
base current of transistor
base current of transistor
also increase. Since transistor 01 02 provides a constant out-
put current which is present both
increase
0103
emitter current and that
This decrease
from the Supply, and will lower the output voltage to the
.
correct level. The regulator circuit is designed to hold the
output constant within a few millivolts for a full range of loads
the output terminals .
Diode 0105, capacitors
capacitor C10B eliminate overshoot during turn-on and turnoff of the Supply. Resistor R113 sets a negative bias current
through current-metering resistor R109 equal to the positive
current drawn by the regulator. This allows the meter to indi-
cate the true supply output current when the Meter switch is
correctly positioned.
ZD1
09. Constant current for
as
OB
in
0105
collector current will cause a reduction
base current. As
in
the current from 01 decreases the current
ZD1
09 is provided by
0107
and 010B compare a portion
set by control R7 with a portion of the
0108
will increase. The
will drop, causing
0106
. This causes
0105
and its collector current will
0103
base current decreases, its
of
transistor
C1
02 and
C1
an
increase
an
increase
at
0103
and
01,
will also decrease.
04, with diode
CURRENT LIMITER
0105,
0110
in
in
in
of
as
the
the
the
any
in
at
and
OUTPUT AMPLIFIER
The output amplifier of the 20-volt supply consists
transistor which
connection. Resistor
higher operating temperatures.
is
driven by transistor
R5
stabilizes the output amplifier
0103
in
a Darlington
METERING CIRCUIT
Switch SW4 selects any of the six output functions to be
monitored by the meter. NOTE: This switch function does
select
or
affect any of the outputs at the front terminals of the
Tri-Power Supply.
of
a power
Transistor
R 109. This resistor carries the output current. As the voltage
across R109 reaches approximately .
conduct taking some
transistor 01 03.
0104
transistor
at
off.
indefinitely.
0104
senses the voltage drop across resistor
55
volts,
of
the current from the output of driver
As the voltage across
will conduct fully, taking
0102.
This causes transistors
In
this manner, output current limiting can be maintained
R1
09 increases further,
all
of the current from source
0103
not
0104
and 01
starts to
to
turn
Page
16
CALIBRATION
( )
At
the two sides of the cabinet top, .remove the six
1/4 screws from the Power Supply assembly. Set the
screws and the top aside temporarily.
NOTE:
Do
not plug the Tri-Power Supply line cord into
outlet until you are instructed
to
do so.
#6
an
AC
x
( ) Locate the small hole in the front panel directly under the
center of the meter. Using a small screwdriver, carefully
and slowly turn the small meter adjust screw until the
pointer is positioned over the
meter scale.
"0"
at the left side of the
( ) Preset the front panel switches and controls as.follows:
POWER switch:
METER switch: B VOLTS.
SUPPLY A control: Fully clockwise.
SUPPLY B and A TRACKING B controls:
Fully clockwise.
MODE switch: TRACKING.
Refer to Figure 9 for the following steps.
NOTE: Periorm the following steps only if the meter pointer is
not directly over the
OFF.
"0"
(zero) on the meter scale.
__
rEA~
METE
R
ADJUST
HO
LE
o
10
S
P~2
'-
____________
T~I-POW"ER
OfF
POWER
SUPPLY
ON
@miW-J
71 B
@
CAUTION: WHEN THE LINE CORD IS CONNECTED TO
AC
OUTLET, HAZARDOUS VOLTAGES ARE PRESENT INSIDE THE CHASSIS. REFER TO THE CHASSIS DRAWING
ON PAGE
VOLTAGES ARE PRESENT. DO NOT PUT ANY PART OF
YOUR BODY OR ANY TYPE OF TOOL
WHILE THE LINE CORD IS PLUGGED INTO
LET.
( ) Plug the line cord into an AC outlet and turn the POWER
55
~
11
TO LOCATE THE AREAS WHERE THESE
switch ON.
£::::0::'
r "Ol
TS
-
L
M,W
S -
r VO LT S
5~AMPS ~
5V . 1.5A
- +
~
@(
IN
THESE AREAS
AN
AC OUT-
AN
I
I
I
Figure 9
Page 17
Figure 10
( ) Refer
to
Figure 10 and adjust circuit board control R216 This completes the calibration of your Tri-Power Supply.
until the painter is directly over the "20" on the upper
meter scale. ( ) Turn the POWER switch OFF and remove the line cord
Turn the METER switch
On
the circuit board, adjust control R116 until the painter
is
directly over "20" on the upper meter scale.
Set the MODE switch
should now indicate between "19" and "
upper meter scale.
to
A VOLTS.
to
INDEPENDENT. The painter
21"
on
from the
( ) Position the cabinet top onto the Power Supply assem-
bly, and secure each side with three of the
screws previously removed.
the
AC
outlet.
#6
x 1/4"
Page
18
APPEN'DIX
This
section
nents
necessary
X-Ray
View
Component
referred
X-Ray
View,
of
the
Manual
for
instrument
and a Schematic
PARTS LIST
values
and
to
on
the
Schematic
and
in
includes a Parts
circuit
related
Figures
List
of
all
maintenance, a Circuit
Diagram.
component
Diagram,
.
numbers
on
the
Circuit
compo-
Board
are
those
Board
CHASSIS-MOUNTED COMPONENTS
CIRCUIT
Comp
Number
PART
.
No.
DESCRIPTION
Resistors
Rl
R2
R3
R4
R5
R6
R7
R8/R9
Rl0
Rll
R12
R13
1-25
1-19-1
2-296
2-94
1-1
1-1
10-281
12-156
NOT USED
2-323
2-
181
2-323
kIl, 1/2-watt, 10%
47
n, 1-watt, 10%
220
150
n, 1/2-watt ,
0.1
n,
1/2-watt,
41
n,
1/2-watt, 10%
47
n,
1/2-watt, 10%
10k.{} control
kn
Dual 10
19.95
kIl, 1/2-watt,
5490 n (5.49K), 1/2-watt, 1%
kIl, 1/2-watt,
19.95
1%
1%
control
1%
1%
Capacitors
Cl
C2
C3 21-173
C4
C5
C6
C7
21-72
25-822
21-99
21-16
21
-16
21-16
JLF,
JLF
JLF
JLF
1.4
JLF
JLF
disc
disc
disc
.005
12,000
.0022
0.2JLF disc
.01
.01
.
01
kV
disc
electrolytic
disc
CIRCUIT
Compo
Number
PART
No.
DESCRIPTION
DJodes
01
02
57-42
57-42
3A 1 silicon rectifier
3A 1 silicon rec1ifier
Transistors and Integrated Circuit
01
02
ICI
417-282
417-282
442-30
MJ2841 transistor
MJ2841 transistor
UA309K integrated circuit
Switches
SWI
SW2
SW3
SW4
60-2
60-54
60-2
63-1257
Slide switch (Power)
Slide switch (Line)
Slide switch (Mode)
Rotary switch (Meter)
Miscellaneous
Tl
Ml
PL1
Fl
54-918
407-718
412-15
421-1
Power transformer
Meter
lamp
Neon
1-1/2-ampere fuse
Page
19
CIRCUIT BOARD COMPONENTS
CIRCUIT
Comp.
Number
PART
No.
DESCRIPTION
Resistors
R101
R102 1-16
R103
R104
R105 1-22-1
R106
R107
R108 1-157
R109
R110
R111
R112
R113
R114
R115
R116
R117 1-157
R118
R119
R120 NOT USED
R121
R122 1-128
R123
R124
R201
R202
R203 1-46
R204
R205
R206
R207
R208
R209
R210
R211
R212
R213
R214 1-20 10
R215 1-48 390 n , 1/2-watt, 10%
R216 10-918 500 n control
R217 1-157
R218
R219
R220
R221
R222
R223
R224
1-24
1-46
1-8
1-9
2-24-12
3-8-1
NOT USED
1-90
1-90
1-56-1
1-20
1-48
10-918
1-24
1-89
1-24
2-265
2-247
1-24
1-16
1-8
1-22-1
1-9
2-24-12
1-157
3-8-1
NOT USED
1-90
1-90 2000
1-56-1
k!l, 1/2-watt, 10%
33
4700
n,
1/2-watt, 10%
3900
n,
1/2-watt, 10%
820
n,
1/2-watt, 10%
1500
n,
1-watt, 10%
1000 n , 1/2-watt, 10%
555
n,
1/4-watt, 1%
470 n , 1/2-watt, 5%
1.1
n,
3-watt, 5%, wire-wound
2000
n,
1/2-watt, 5%
n,
2000
1200
10
390
500 n control
470
33
2400
33
62
12
5000 n (5K), 1/2-watt, 1%
33
4700
3900
820
1500
1000
555
470
1.1
2000
12oon,
1/2-watt,
n,
1-watt, 10%
k!l, 1/2-watt, 10%
n,
1/2-watt, 10%
n,
1/2-watt,
k!l
, 1/2-watt,
n,
1/2-watt,
k!l
, 1/2-watt, 5%
k!l, 1/2-watt,
.2 k!l, 1/2-watt, 1%
kn,
1/2-watt, 10%
n,
1/2-watt, 10%
n,
1/2-watt, 10%
n,
1/2-watt, 10%
n,
1-watt, 10%
n,
1/2-watt, 10%
n,
1/4-watt,
n,
1/2-watt,
n,
3-watt, 5%, wire-wound
n,
1/2-watt,
n,
1/2-watt,
1-watt, 10%
5%
5%
5%
5%
5%
1%
5%
5%
5%
k!l, 1/2-watt, 10%
470
n,
1/2-watt,
33
kn,
1-
24
1-89 2400
NOT USED
1-24
1-128
2-265
2-247 5000 n (5K) , 1/2-watt, 1%
1/2-watt, 5%
n,
33
kn,
1/2-watt,
62
k!l, 1/2-watt, 5%
12
.2 k!l, 1/2-watt, 1%
1/2-watt,
5%
5%
5%
CapaCitors
C101
C102 25-116
C103 25-192
C104
C105 25-283
27-47
25-251
0.1
50
J.'F
2000
50
J.'F
10
J.'F
J.'F
Mylar'
electrolytic
J.'F
electrolytic
electrolytic
electrolytic
CIRCUIT
Compo
Number
PART
No.
DESCRIPTION
Capacitors (cont'd.)
C106
C107
C108
C109
C201
C202
C203
C204
C205
C206
C207
C208
C209
21-9 100 pF disc
21-48
25-251
25-283
27-47
25-116
25-192
25-251
25-283 10
21-9 100
21-48
25-251
25-283 10
50
10
0.1
50
2000
50
.05
50
Diodes
0101
0102
0103
ZD104
0105
0106
0107
ZD108
ZD109
0110
0201
0202
0203
ZD204
0205
D206
D207
ZD208
ZD209
0210
57-65 1N4002
57-65 1N4oo2
57-65 1N4oo2
56-50
57-65
57-65
57-65
56-57 1 N716A zener
56-31
57-65 1N4oo2
57-65 1N4oo2
57-65 1N4oo2
57-65
56-50
57-65 1N4oo2
57-65
57-65 1N4oo2
56-57
56-31 PS18775 zener
57-65
00-7
1N4oo2
1N4oo2
1N4oo2
PS18775 zener
1N4oo2
00-7
1N4oo2
1 N716A zener
1N4oo2
Transistors
0101
0102
0103
0104
0105
0106
0107
0108
0201
0202
0203
0204
0205
0206
0207
0208
'Registered
417-801
417-201 X29A829
417-294 MPSA42
417-801 MPSA20
417-801 MPSA20
417-201 X29A829
417-258 TIS87
417-258 TIS87
417-801 MPSA20
417-201 X29A829
417-294 MPSA42
417-801 MPSA20
417-801 MPSA20
417-201 X29A829
417-258 TIS87
417-258 TIS87
Trademark,
MPSA20
.05
J.'F
J.'F
J.'F
J.'F
J.'F
J-LF
J.'F
J.'F
pF disc
J.'F
J.'F
J.'F
DuPont
disc
electrolytic
electrolytic
Mylar
electrolytic
electrolytic
electrolytic
electrolytic
disc
electrolytic
electrolytic
zener
zener
Corp.
Page
20
CIRCUIT BOARD X-RAY VIEW
NOTE:
purpose
To
find the PART NUMBER of a component for the
of
ordering a replacement part:
A. Find the circuit component number (R111, C1
etc.)
on
the X-Ray View.
01,
in
B. Locate this same number
Number" column
C.
Adjacent to the circuit component number, you will
find the PART NUMBER and DESCRIPTION which
must be supplied when you order a replacement
part.
of
the "Circuit Component
the "Parts List. "
7
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