B+K precision 1602 User manual

I
SOLID
STATE,HIGH.VOLTAGE,
REGULATED
DCPOWER
SUPPLY
i
trIYNASCAN
COF|POF|ATION

CONTENTS
PAGE
SPECIFICATIONS 3
FEATI.JRES 3
INTRODUCTION 4
OPERATING
CONTROLS 4
OPERATING
INSTRUCTIONS 5
APPLICATIONS .....7
CIRCI.JIT
DESCRIPTION . . .I1
MAINTENANCE .....13
CALIBRATION.l3
FUSE
REPLACEMENT . .. .14
WARRANTY Cov-3

INPUT
VOLTAGE
4OOV
DCSUPPLY
Output
Voltage:
Output
Current:
Grrrent
LimitAdjust-
ment/Protection:
LoadRegulation:
Line
Regulation:
Noise
& Ripple:
IOOV
DC
SUPPLY
Output
Voltage:
Output
Current:
Load
Regulation:
Line
Regulation:
Noise
& Ripple:
Protection:
6.3VAC
(Non-Adjustable)
Output
Voltage:
Output
Current:
Protection:
12.6V
AC
(Non-Adj
ustable)
Center-Tap
Supply
Output
Voltage:
Output
Current:
Protection:
METERING
Voltmeter(2Ranges):
Milliammeter:
DIMENSIONS
(Overall);
NET WEIGHT:
SPECIFICATIONS
105
- I25VAC,
60
Hz
0 - 400V,continuously
vari-
able.
0 - 20OmA.
lOmA to 200rnA,continu-
ouslyvariable-sets
trip cur-
rent
toshut-down
supply
out-
put.
0.1%
athigh
end.
0.t%.
Less
than
lOmV
peak-to-peak.
0 - 100V,
continuously
vari-
able.
0 - 2mA.
r%
lVo
Lessthan1OmV
peak-to-peak.
Current-limiting
resistance.
6.3V!57o,
full load; I IOVAC
primary.
3.5Acontinuous.
Thermal
circuit-breaker.
6.3V
!5%,fuII
load;
II0VAC
primary,
each
side
to
center-tap.
3.5A
continuous.
Thermal
circuit-breaker.
0to 400V
DC
(400Vsupply
only),
!37o.
0to l00VDC
(100V
supply
only),!3%.
Range
selected
byswitch.
0to 200mA
(monitors
400V
supply
only),
t3%.
14-118"
x 3-7
f
8"x 10"
deep.
II lbs.
FEATURES
Fullysolid
state,
utilizing
integrated
circuits,
silicon
transis-
torsand diodes
andone
SCR.Among
the advantages
of
solid
state
construction
are
dependability,
no
warm-uf
time
orstabilization
delay,
ruggedness,
compact
size.
CurrentUmiting/Overload
Protection:
Protects
load and
instrument
against
overload.
Pre-settable
automatic
current
shutdown,
fully adjlstable
froml0rnAto 200mA
provided
on.the
B+output.
Resistive
limiting
protects
the
C-supply
andload.
The
6.3VAC
and
the
12.6{IAC
heater
windingdinb
loads
are
protected
byaresettable
circuit
breaker.
SimplifiedCunentShutdown
Setting:Permits
setting
B+
current
shutdown
point without disturbingexternal
load
connections
or output voltage
settings;
doesnot require
application
of shortcircuit to output terminals.
sirirply
press
thebutton
and
adjust
theCURRENT
SETcontroi
tb
the
desired
setting
on
the
currentmeter.
O400V,
G200mA:Output
voltage
continuously
adjustable
over.entire
-rgnge
wjth gsingle
control;
norange
switching
required.
Fullyregulated
output
atall levels.
G100V, G2mA: Output voltage
continuously
adjustable
gver.
entire rang€
with a single
control; indepehdently
tloating
output.
Canbe
used
independently
of the0400V
oglpgtorcan
be
usedwitheither
polarity
referenced
tothe
400V
output.
6.3VAC,
I2.6VAC
CT,
G3.5A: Independently
floating
AC
sources.
Dual Meters:Allow B+ supply output voltage
and B+
supply
current
drain
to bemonitored
simultanebusly.
The
voltmeter
can
also
beswitched
to monitor
thebias
iupply
voltage.
Bothmeters
have
overloadprotection
to prevent
damagefromexcessive
loading.
one current Range:
Simplifies
current shutdown
setting
byrequiring
only
one
adjuitment.
TwoVoltmeter
Ranges:
0-400V
and
Gl00V ranges
for the
B+ andC: supplies
respectively
provide
maximu=m
resolu-
tionwith aminimum
effort to the
user.
Standby-DC
On
Switch:Disconn€cts
the
DC
supplies
from
external
loads
without disturbing
voltage
or iurrent set-
tings.
Pilot-Lamp: Lights up to indicateat a glance
that the
supply
is
on.
Mechanical
he-Regulator:B+ supply rectifier voltage
is
increased
in progressive
steps
asoutputis increasea.
inis
improvesefficiency
as
lesspower
is converted
to heat
at
low
voltage
output.
Floating
outputs: Permit
referencing
thepositive
or nega-
tive outp_uls
of the
-B+ supplyandthe C- supplyto any
external
DCpotential
orgrounds.
Reverse
?olarity hotection: Prevents
against
accidental
damagefrom reversepolarity connections
to an external
power
source.
Attractive, Functionaltlesign: Permits
stacking
of units
when
more
than
one
power
supply
isrequired. -
E"ry t9.Ope_rate:
All controls
are
identified
andeasy
to
rgad-Simplified
operation
helpsprevent
operator
mistakes
thatmightdamage
equipment.
-

The B & K PrecisionModel 1602 High Voltage Power
Supply is a versatile,
laboratory quality instrumentwhich
pr6vitiesregulated
DC voltages
and currents
of 0-400V at
bZOOmn and G100V at G2mA; and AC voltages
and
currents
of 6.3 and I2.6VAC at 0-3.5A.
The highperfor-
mance, operating ease,and special featuresmake it an
excellent
^choice-
for most applications requiring a high
voltage DC power source.
It is well'suited for,powering
fully-solid siate circuits, tube type circuits,.
andhybrids.
Unlike somesupplies,
the usercan rectify the AC.source
and
have
3 indefendentsupplies
for poweringdigital/analog
circuits,
etc.
Following is a list of some
of the most popular applications
of 1602:
oServiceTechnicians: Poweringhigh voltage solid state
equipment, or individual circuits consistingof transis-
tors,
vacuum
tubes
or both.
oFactory Technicians: Powering complete equipment
or individual assemblies
during testing in the factory.
o
Engineers
and l:boratory Technicians: Poweringpro'
totypesand
experimental
equipment.
oElectronics Instructors and Students: Laboratgry ex-
perimentsin basicandadvanced
electronics.
CONTROLS
14 12 11
Fig. 1. ControlsandIndicators.
INTRODUCTION
OPERATING 8
6
l.
2.
CURRENT METER. Measures
actual B+ output load
current duringnormal.operation.
IndicatesBt current
limit whenset/resetswitch 3 ispustred.
B+ CURRENT SET. Providesadjustment of B* cur-
rent limit. Continuously adjustable from l0-200mA
output current.
B+ CURRENT
PUSH
TO SET
ANDRESET
(SET/
RESET)BUTTON:
When
fully depressed and
held,
connectscunentmeter
1 foreadtheB+current
limit
setting.
When
pressed
andreleased,
resetsB+overload
circuitif it hasbeentripped.
OVERLOADINDICATOR (RED). Lights when B+
current
limit has
been
exceededand
theB+zupply has
strutdown.
STBY ON. STBY position: Removes
power from
terminals
8, 9, 13,and
14, and voltmeter10, but
leavesthe DC suppliesactivatedand at standby
condition.ON posifion: Appliespower to oirtput
terminals
8, 9, 13, 14,and
voltmeter10.
6. POWER.
Ughts continuously
whenpower supplyis
turnedon.
7. TERMINAL. Earthand
chassis
groundterminal-
B+ TERMINALS
8. +TERMINAL. Positive
polarityof B+output.
9. -TERMINAL. Negative
polarityof B+output.
10.VOLTMETER.
Indicates
output voltage
of B+ or C-
srpplies.
ll. METER
RANGE.
B+/G400
position:
Selects
full scale
ranse
of400volts
forvoltmeter
10
tometer
$+output
vollage.C-/G100
position:
Selects
full scale
range
of
100f forvoltmetei
10
tometer
C-
output
voltage.
12. LEVEL (B+).Turns off power supplyat extreme
counterclockwise
rotation.
Clockwise
rotationturns
on
powersupplyandadjusts
B+outputvoltage
upwards.
3.
4.
5.
og
@
@
B@e

C-TERMINAI,s
13.- TERMINAL.
Negative
polarity
odtput
of C-supply.
14.+ TERMINAL.
Positive
polarityoutput
of C_
supply.
15.C- CONTROL.
{,{gsts C- outputvoltage
between
terminals
13 and 't4 from
0 to-100V
witf,clockwise
rotation. Output voltage
is monitoredon Volt-
meter
10 when METER RANGESwitch
1l is in
C-lGl00V
position.
16.
& 17.6.3VAC
TERMINAIS. 6.3VAC output rer-
minals.
Protected
by
breaker
19
16.& 18. 12.6VAC TERMINALS. l2.6VAC output ter-
minals.
Protected
by breaker19
19. AC RESET.
Circuit
breaker
in serieswith terminal
16
protects
againstexcessive
overloads
between
terminals
16,17
and
16,18.
NOTE: At17 and186.3VAC
is available.
This
output
is
protected by an internal fuse. For maximum
convenience
and minimum down-time due to
accidental
short-circuits
use
the
breaker-protected
AC
outputs
16 , 17 and16, 18.
OPERATING
l. Turn off the power supplybefore
plugging
it into an
AC outlet, by rotatingthe LEVEL control 12 fully
counterclockwise,
until it "clicks" off.
2. Connect
the power
cordto a 105-125
volt 60Hz AC
outlet. WARNING
INSTRUCTTONS
(b) Push
the SET/RESET
3 button in andadjust
the B+ CURRENT
SET
2to atleast
50mAon
CURRENT
METER
1 if not already,
and
reset
to thedesired
currentlimit.
(c) Release
the SET/RESET
3 button andreturn
STBY/ON
5to ONpostiition..
If an overloadin the circuitry being powered
exists,
the supply
will shutdown
as
normal.
At very low output currents,
decreasing
the B+
output voltage between l50V to 400V may
activatethe QI-VCE sensing
circuit before the
desired
B+output isreached
on VOLTMETER
10.
The supply will shutdown and the OVERLOAD
lamp 19 will light. To reset, simply proceedas
stated
in (a),
(b),and
(c)above.
5. Connect
the.
powe_r
supply
output to the device
being
powered
with test
leads
asfollows:
a. connect th9 positive
polarityhigh voltage
input of
the device
being
powered
to the(+) teririnaf 8 of
theB+supply.
b. Connect
the negative
polarityhighvoltage
input of
the device
being
powered
to the(-) terminaf g of
the
B+supply.
c. If thepositive
polarity of the device
being
powered
is to be
^the ground reference,
j_lrmpei
the
.
(+)
terminal 8 to the
ground
terminal 7 .-
If the negative
polarity of thedevice
being
powered
is to be^the ground reference,
conneJt^
the o
terminal 9 to the
ground
terminal
T.
If neither
thepositive
or thenegative
polarityinput
of the device
being
powered
needs
to begrouniled
but the chassis
of the deviceneedsgrounding,
connect
a separate
testlead
from the chassis
of the
device
to theground
terminal 7 of the B+ supply.
d. Follow the.aboveprocedures
for the C_
supply,
u.silg^plus (+) terminal 14 and minus (-) teiririir_
13. NOTE
Ih.r C- -supply and the B+ supply are entirely
independent
of each
other.
When
aiircuit requires
a.bias
voltage
which
isnegative
with respect
to the
circuit reference,
the (+) terminal 14-of the C-
supply
isconnected
to this
reference.
Refer
to Fie.
2.
e. Connect the AC voltage sources(termin_
als 16 , 17 andlor 1G
, 18lto the device
if ;;_
quired.
a. Use
only a polarized
3-wire
outlet.
This
assures
that thepowersupply
chassis
is
connected
to a
good.earth.
ground and prevents
danger
from
electrical
shock.
lf a 2-wire
to 3-wire-
adapter
m_ust
be used,
be sure
the groundwire of the
adapter
isattached
to agood
earthground.
b.If acircuit under
test
requires
application
of a
fixed bias,always
apply the required
voltage
using
the_C-
supp-ly
first; before
applying
theIi'+
voltage(Step
6-d).
4.
Turn gn-lhr_ qower supply by rotating the LEVEL
control 1Z slightly clockwise
past the-.,click". The
POWER
indicator 6 will light. -
Determine the maximum safe load current for the
device
to be powered
and setthe automatic
current
strutdown
for thatvalue
asfollows:
a. Push
and
hold theset/reset
bu_tton
3 and
adjust
the
B+ CURRENTSETcontrol 2 for thedesired
shut_
down current point as read on the CURRENT
meter 1 .
b. Release
theset/reset
button 3 .
c. Turn
-LEVEL (B+) control 12 to the desired
voltage.
d. If themaximumsafeload
current
isunknown.
start
with alow current
setting.
If thesetting
istoo low,
the overload
circuitwill trip when
pow6risapphed
to the loadin steps
6 and 7.lfio, increair'tf,.
current
_
setting in small stepsuntil the overload
circuitdoes
not trip during
normal
operation.
NOTE
In certain conditions of high-linevoltages
or B+
OUTPUT.
voltages
gre,ater
ihan 100V,-resetting
rygy.not be accomplished
by simply pushing
thJ
SET/RESET
3buttbn.
(Thisis
Oue
t6the
qr-"VCE
sensing
circuitry
described
under
CURRENT-VCE
SENSING
CIRCUITS,
page
13.)
Should
this
occur
proceed
as
follows:
(a) Set the STBY/ON
S switchto the STBY
position.

H6Bm"
sr
Returnthe STBY-ON
Switch5 to the ON position
and
setthe
output
voltage
as
follows:
a. Set METER
RANGESwitch
to C-l0-
100Vwhen
adjusting
C-supply
output.
b. TurnC-
control 15 untildesired
voltage
is
reached.
Flg. 2. Typical VacuumTube Circuit Application.
lncrease
the strutdownpoint slightly with the
B+ CURRENT SET control 2 .lt the normal
load currentisunknown, thistechnique
maybe
used,but, if the current limit is already
set
for
the maximumsafe
loadcurrent,do not increase
thecurrentlimit further.
Check the bias setting to determine if it is
incorrectlyset.
(5) Refer
to NOTEunder
4d, Page
5.
NOTE
Some equipment has a highly capacitiveinput,
which resultsin a surgecurrent when power is
initially applied.Whenpoweringsuch
equipment,
the overl,oadcircuit may activiate when the
STBY-ONswitch
isplaced
in theON positionwith
full operatingvoltagepreviously
set.If this occurs,
reduce the voltage setting before resetting the
overload and then bring the output level up
gadually to allow thecapacitors in theequipment
to charge;
thiseliminates
thesurgecurrent.
c. If the power supply continues
to shut dodn at the
correct current setting, check the load circuits to
determine
thereason
for the overload.
d. To remove
power from the load without disturbing
the voltage or current shutdown settings,set the
STBY-ON
switch 5 to theSTBYposition.
e. Refer
to NOTEunder
4-d,
page
5.
GTN
H
(3)
6.
c. Set the METER RANGE switch 11
whenadjustingB+ supply
output .
d. Turn LEVEL control 12 clockwise
reached. until voltage is
NOTE
Whena fixed biasis requiredfor a circuit under
test, always
perform Steps
a and b first. (C- bias
level.)
7. If the B+ load current exceeds
the current shutdown
point, the overload lamp 4 will light, and the B+
supply will shut down (cunent meter 1 and volt-
meter10 will drop to zero).Restore
thepowersupply
to normaloperation
as
follows:
a. To reset the power supply, pressand releasethe
set/reset
button 3 . If the overloadwas intermit-
tent, thiswill restore
normaloperation.
b. If the overloadlamp remainslit, use one of the
following techniques before resetting the power
supplyagain.
(l) Reduce
theloadcurrent.
(2) Reduce the voltage slightly with the LEVEL
control 12 .
to B+/G400V (4)

General
This instrumentmay beused
to poweravastassortment
of
circuits and devices
in the fields of electronics
servicing,
electronicsmanufacturing,electronicsdesignengineering,
and electronics
education.
The l+ and C- supply outputs
are fully adjustable
over their full range,while the low
voltageAC iource remainsfixed. This flexibility makesit
suitable
for most applications
requiringasingle
or multiple
output highvoltage
supply.
PoweringTube Type Circuits
Fig.2 shows
the 1602beingusedto supplythe operating
voltagesin atypicalvacuum.tube
RF amplifierstage.
l. Connect
the filament of the tubeto terminals 16 and
17 for 6.3VAC heateroperation
or to 16 and 18 if
l2.6VAC heater
voltage
isrequired.
2. Connectthe grid resistorto the(-) terminal 13 of the
C-supply.
3. Connectthe (+) terminal 14 of the C- supply to the
(-) terminal 9 of theB+supply.
APPLICATIONS
4. Connectthe B+ lead to the (+) terminal I of the B+
supply to providepower for the plate and screen
grid
of thetube.
5. Connect
thecommon
lead
to the
(-)terminal 9 of the
B+supply.
Thispoint isalso
normallyconnected
to the
groundt6rminal-
7 , for strock
hazatdprevention.
The
ionnection between
groundand the (-) terminal 9 of
the B+ supply may not be used
during some
typesof
experimentJ,
-
such as positive grounds and floating
supplyinputs.
With the meterswitch
in theC-/G100V position,adjust
the
C-control for the desired
bias
level.
Before the S+ output voltage is adjusted,pressthe B+
currentset/reset
button andadjusttheB+CURRENTSET
control for the maximum output current desired.
Now the
S+ voltagelevel may be increased
to therequired
level-
If
the current overloadcircuit shuts down the B+ output,
either increase
the B+ current set, or decrease
the output
current drain by increasing
the C- output voltage.(Also
referto NOTE under4'D, Page
5.)
\
t-)
I
=
GIN
H
Vcc
g6:gB6Em"
SIG OUT
Fig. 3. Typical Triinsistor Circuit Application.

Powering
TransistorType Circuits
Fig. 3 shows
the 1602
PowerSupplybeing
used
to powera
transistof
amplifiercircuit.
l. Connect the Vcc lead of the circuit to the (+)
terminal 8 of theB+supply.
2. Connect the common lead of the circuit to the (-)
terminal 9 of the B+ supply and to the ground
terminal 7.
EQUIP},IENT
BEING
POWERED
In somecircuits
the
chassis
is connected
to thepositive
Vcc
line which meansthe groundterminalshouldbeconnected
to the (+) terminal 8 of the B+ supply.Fig. 4 shows
the
various methods to connect the 1602 to accommodate
different equipmentpower/ground configurations.
If there
is any doubt which supplyleadis common to the chassis,
nodamage will result
if aseparatelead
isconnected
from the
chassis
to theground terminal 7 .
EQUIPI\4ENT
BEING
POWERED
Fig.4. Power
Supply
Output Situation.
Other Educational Uses
The student in an electronics
coursemay use the power
supply for powering equipment and circuits as
previously
described
for all other applications.In addition, thepower
supplycan be usedto conductexperiments
in fundamental
electronics.
In learning
Ohmslaw,for example,
therelation-
strips
of resistance,
voltageand current are easily demon-
stratedwith the supply.Beingableto observe
both voltage
and current simultaneously
is a geat aid in suchexperi-
ments. Fig. 5 shows some examples of the types of
experiments
that maybeconducted.
UsingTwo Suppliesfor Two B+ Voltages
Whrn two separate
B+ voltages
arerequired
simultaneously
for testingequipment, two supplies
may be used.
Setthe
voltage
andcurrent limit for each
supplyindependently
as
required by each load requirement. Only the circuit
reference
point mustbecommon
betweenthetwo supplies.
Fig. 6 shows
some
typical examples
of properpower supply
connections
when usingtwo units. Take extra precautions
to prevent reverse polarity connections
in suchsituations.
The numerous connections can become confusing. Ad-
ditional colorsfor the test leadswill behelpful. The'power
suppliesare protected from reverse
polarity damagefrom
anexternalvoltage
source
suchasthe other powersupply.
8
Although two suppliesmay be used safelyin the above
situations, it is not recommendedthat the suppliesbe
operated
in series
for voltageshigher than 400V. Also, to
avoidshockhazards,
donot connect
both groundterminals
to the power supplyoutput terminals;
doing somay place
theentirepowersupply
chassis
at ahighpotential.

@oo
E@= cEl
E@e
OBSERVE
CHARACTERTSTIC OF DIODE
MEASURE
Vnt &
VARY
ETN
I
IMEASUREVot & I
VARY Etrv
OF ZENER DIODE
II{EASUREVVnt &
VARY Eru
OBSERVE
OHMS IJAII
E
^-T
BASIC CURRENT DIVTDER
rnr
^ -a>
*-.
12-tr*
#fu,
r1=
tr*
sfu;
11+12
=
tT*
r1
-
Fig. 5. Typical Laboratory Classroom
Experiments
Usingthe 1602PowerSupply.
CHARACTERISTIC

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C'eneral
The power supply convertsa llTVAC input to a highly
regulatedand filtered DC output that is fully adjustable
from 0 to 400 volts at G200mA at the B+ terminals;
and
G100V at 0-2mA at the C- terminals.The supply also
converts
its AC input to a l2.6VAC center-tappedoutput
at G3.5A. The circuits that accomplish
this action may be
divided
into 4 maingroups as
follows:
l. Unregulated
DC and AC sources:
Converts
the AC
input to raw DC for the B+ and C- control and filter
circuits;andstepsdowntheAC input for the l2.6VAC
filamentwindings.
2. Control circuits: Control the unregulatedB+ and C-
sources to provide the highly regulated, adjustable
outputs.
3. Current sensingcircuits:Establish
theB+currentlimit,
sensethe B+ load current, and activatean overload
detectorthat shutsdown the B+ supply if the current
limit isexceeded.
4. Metering: Monitors the B+ or C- voltage,and the B+
output current.
Refer
to Fig.7,thefunctional
diagam
and to the schematicdiagram. Circuit descriptions
make
constantreference
to these
diagrams.
NOTE: The voltages
in the following circuit descriptions
and on the diagramsare measured with respectto the
regulated
B+ output, the + terminal,or the C- output, and
- terminal. Note that thesepoints are floating indepen-
dently of thechassisof thepowersupply.
Unregulated
DCand AC Sources
There are three unregulated
DC sources
and one unregu-
lated AC source in the supply. The most important
unregulated
supply is the B* source.This source
converts
I ITVAC to arawunregulated
B+output. Later,the control
andfilter circuits
convertthisto the regulated
B+ output of
thepowersupply.
The unregulated
B+ output levelis pre-regulated
in coarse
steps.
As the LEVEL control isrotatedclockwise
from zero
to maximum,the unregulated
B+changes
from itslowestto
its highest value
in four steps.
Thisminimizesthedifference
betweenthe unregulated
B+ and the regulated
B+ output,
whichalwayskeeps
powerdissipationwithin safe
limits.
The main components which make up this circuit are
winding No. 1 of power transformer
Tl, pre-regulator
switch assembly
52, rectifiers D5, 6, 7, 8, and filter
capacitor
C8.
The AC input is applied to the unregulatedB+ circuit
through on-off switch 54 (which is part of the level
control) acrossneonlamp NEI (which glows
continuously
as a pilot lamp to show that power is on) to power
transformer
T1.
Transformer
Tl hasfour taps
in its output windingNo. l.
At the lowestvoltage
setting,
only the low voltage
portion
of the winding is connectedto the rectifiers (this is the
condition shownon theschematicdiagram).
As the LEVEL
control is rotated clockwise,
cams
operate
microswitches
S2C, then S2B, and finally S2A. Each cam-operated
microswitch selectsanother tap on this secondaryof the
transformer and sequentially steps the rectifier input
voltage
to ahighervalue.
Rectifier diodesD5, 6, 7, and8 converttheAC to full wave
DC, which is filtered by C8. The unregulated
!+ output at
C8isregulated
andfilteredby the control circuits.
CIRCUIT DESCRIPTION
")
3.
4.
The C- and CONTROL unregulated
DC sourcesarefairly
standardandstraightforward.
Secondarywinding No. 2 providespower for the com-
parator
ICI andvoltage
reference
and
erroramplifier IC2.
This supply is designed
to be free of influence from the
unregulated B+ supply. The 20 volt AC output from
secondary
windingNo. 2 isconverted
to +15V and
-15V
by
full wave,rectifiers
Dl and 2. Both the V+ and V- voltages
float with respectto the regulated
output and the unregu-
latedB+supply
variations.
Secondary
windingNo. 3, diodeD9 andCll provide
half
wavefilteredDCfor theC-control andfilter circuits.
B+andC-Control Circuits
The B+ control circuit converts
the unregulated
B+ supply
into the regulated
l+ output voltage.The control circuit
establistresthe regulated
B+ output voltagein responseto
the settingof theLEVEL control R22.WhenR22 isset
for
0volts,thefollowing circuit conditions
exist:
VoltagereferencelCzA provides astable
+7V reference
atlC2-6.
The +7V reference is dividedacross
RlO and Rl l to
place
+3.5Vat pin 4,IC2, the inverting
input of error
amplifierIC2B.
Theregulated B-voltageis 0V.
The +7V reference is divided acrosscurrent Path I,
which consists of R23, Rl2, R30, and R2l (R22 is
approximately 0 ohms at this time). This places
approximately
+3.5V on IC2-5,the non-inverting
input
of erroramplifierlC2-13.
Error amplifier lC2B will producewhateveroutput is
necessary
to keep the differencevoltageat its inputs,
pins 4 and 5, very closetogether.
Therefore,with R22
at about zero ohms,
just enoughdrivewill be applied
to series
pass
regulator
Ql, Q2 to maintaina
zerovolt
B-
output.
The series
pass
transistorsare being slightly drivenat
0V output to avoid non-linearities at low output
voltages
(iumps
in output,
poorregulation,
etc.).
l.
5.
6.
WhenLEVEL control is increased
to a highervoltagelevel
thefollowing circuit actionoccurs:
1. The resistance
of R22 is added
to the voltage
divider
network,decreasingcurrent
I1.
2. The voltageat lC2-5 increases
(less
drop across
R23,
l2), and error amplifierIC2B increases
its output to
driveseries
pass
transistor
Q
l, Q2into heavierconduc-
tion.
3. The regulator
allowssome
of the B+ supply to pass
to
theoutput,and theoutputvoltagerises.
4. As theoutput voltagerises
theB-supplybecomes
more
negative
with respect to theB+ terminal.
5. CurrentI increases asthe B- becomes
morenegative,
and the voltage at IC2-5 decreasesuntil balanceis
achieved.
WhenLEVEL control
R22isdecreased,theoppositeaction
occurs.
Once R22 is setandbalance
is achieved,any load
current changesthat tend to change
the output voltageare
sensed
andcorrected.
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The C- control circuit converts the unregulated
C- supply
into the regulatedC- output voltage.This control estab-
listres
the output level in response
to the settingof the
BIAScontrol,R35.
Thevoltagereferencefor this circuit consists
of D2l ,C14,
and R34. Reference
diode D21 actsasa constantvoltage
source
for R35. The wiper of R35 isconnectedto thebase
of Q3, so the output voltagewill alwaysbe .6V lessthan
the control setting. Any variationsin the unregulatedC-
voltageare absorbed
acrossR34, because
as the voltage
across
D21 increasesaboveits referencevoltage,
its inter-
nalresistance
dropsto drawmorecurrent.
fu 12increases, the voltagedrop acrossR34 alsorisessuch
that the reference
voltage stays constant. Diode D2l is
biasedso that its voltageneverdrops below its reference
point.
If the load on the output increases,
theoutput voltagewill
attempt to drop.Thiswill turn Q3 onharder,
increasingthe
output current,which restores
theoutput voltage.
Theoppositeeffectoccurs
as
theoutput loaddecreases.
Overloaddescription:
Resistance-limited.
Current-VCE Sensing
Circuits
The main components in the current sensingcircuits are
comparatorICl, overload
switchSCR-1,andcurrent sense
resistorRl. This circuit monitors the B+ load current and
sttutsdown the B+ supplyif the load current is exceeded.
The current sensing
resistor,Rl, is selected
so that IV is
developedacross
it when exactly 200mA load current is
drarvn. The voltage acrossthis resistor is applied to the
non-inverting
input of thecomparator,
ph 2,lcl.
The invertinginput, ph 3, is connected
to a variable0-1V
voltage
source,
R5, theBf currentlimit control.
Whenever
the output loadcurrentproduces
avoltageacross
Rl that is greaterthan the presetvoltageon the inverting
input of the comparator,ICl, a positive lV signal
appears
at output pin 7. This output drivesthe gate of overload
MAINTENA}ICE
This power supply is built to provide long, trouble-free
serviceand doesnot requireperiodic maintenance.
If the
unit malfunctions,useconventional
troubleshootiegtech-
niques,such asvoltageand resistor checksto isolate
the
defective
component.
If defectivecomponents
are
replaced
the unit shouldberecalibrated.A note on safety:
Whenever
servicing
this unit keep the level control R22 below one
third rotation (no microswitches
activated) to keep the
maximumDC voltage below l60V DC.Rememberthat the
MAINTENANCE
AND CALIBRATION
switch SCR-I and turns it on. SCR-I grounds
pin l0 of
error amplifier IC2B, which inhibitsits operation
regardless
of all other inputs,shutting
downthepowersupply.SCR-l
also provides the ground path which allows the overload
lamp to light. Set/reset
switch 53 shorts acrossSCR-I,
whenit isdepressed,to replacethecurrentpath.
NOTE
Besidesthe current-sensing function, another cir-
cuit comprised
of R40,D25,D24, andRl7 senses
the collector-emittervoltageof Ql above200V.
During overloads
and some reset conditions the
value of the collector-emitter voltage and the
collector-current of Ql can shift the operating
point of Ql out of its S.O.A. (Safe Operating
fuea) curve.Theavalanche
breakdownof D25 and
D24 is such that for collector-emitter voltages
geater than 200V, a voltageis developed
across
R17 that adds to the voltage developed
by the
output currentacrossRl. Thissummedvoltageon
pin 2 of ICl representsan equivalent power
dissipationvalue that is under the S.O.A.curveof
Q1. Therefore,
when this summedvoltagereaches
the preset voltage
on pin 3 of ICl, astrutdownof
output voltage
andcurrentoccurs.
Metering
Voltmeter Ml is connected
directly across
the output of
the B+ supply
or theC-supply,
to measure
output voltages.
Meter Range switch M selectsthe proper input and the
proper seriesresistor to calibrate the meter for either
G400V full scale,or G100V full scale.
CurrentmeterM2 is actually avoltmetercalibratedto read
S+ output current. The metermeasuresthe voltage
devel-
opedacross
the current sensing
resistor,
which is exactly I
volt for a full scale
meterreading.When setting
thecurrent
limit, switch 53 is actuated,which connectsthe current
meter directly acrossthe B+ current set control R5. This
control selects a voltagefrom GlV, which very accurately
correspondsto thecurrentlimit value
readon themeter.
pre-regulator
cansupplyup
to500VDCtothe board.
CALIBRATION
Useinsulated adjusting tool, and exerciseCAUTION- the
P.C.B.
hasover400V DCpotential at maximum settings.
To gain access
to the calibration adjustments,
removethe 3
screws
at the rearof the top cover,then lift the top coverat
the rear and slide the front lip of the cover from the
retaining bosses
on the front panel. Refer to Fig. 8 for
locations
of calibration adjustments.
The following instructions are for useby qualified personnel
only. To avoidelectricalshock,do not perform
servicingother than containedin the operatinginstructions unless
you arequalified to do so.
High voltage up to 500 volts is present when the power supply is operating. Line voltage (120 VAC) is
presenton the fuseholderand on-off switch any time the.
power supply is connected
to anacoutlet, evenif
turned off. Always observecaution when the top coveris removed.Contacting exposed
high voltage could
resultin fatal electricalshock.
l3

l00v METER
CAL
(R26)
l. Connect
an accurate,calibrated
voltmeter
to the
output
terminals
13 and 14 , capable
of l00V read-
ing-
2. Set the METER RANGE switch 11 of the
supply
to the
C-lG100
position.
3. Adjust the C- control 15 for exactly 100V
power
on the
externalvoltmeter.
4. Adjustl00V CAL potentiometer
(R26)
for exactly
l00Vonthe
voltmeterofthe
1602
power
supply.
MAX. OUTPUT ADJ.(R23)'
3.
1. Connectan accurate,
calibrated
voltmeterto the
outputterminalsSand
9, capable
of 400Vreading.
Set
theLEVELcontrol 12 of the 1602
power
supply
toMAXIMUM.
Adjust
theMAX.OUTPUT
ADJ.
potentiometer
(R23)
forexactly402Volts onthe
externalvoltmeter.
400v METER CAL (R3l)
l. Connectan accurate,calibratedvoltmeterto the
outputterminals
8 and 9 , capable
of 400Vreading.
2. Set the METER RANGE switch11 to the 0-400
positlon.
3. Setthe
LEVELcontrol12 of the16O2
power
supply
toreadexactly
400Voltson
the
external
voltmeter.
4. Adjust400VCAL potentiometer
(R3l) for exactly
400
Volts
onthevoltmeterof the1602
power
supply.
CURRENT
METER
CAL
(R27)
l. Refuce the
1602
LEVEL
control12 tominimum.
2. Connect
an accurate,
calibrated
ammeter
capableof
200mA
in serieswith an
appropriateload
(250ohms,
l0 watts)to the outputterminals
8 and9 of the
1602
power
supply.
3. Adjpst
theLEVELcontrol
"12 forexactly
200mAon
the
external
ammeter.
4. Adjust
CURRENT
METER
CAL.
potentiometer
(R27)
for exactly
2OOrnAonthecurrent
meter
of the 1602
power
supply.
CLTRRENTLIr\ilrT
ADJ(R39)
NOTE: No
load
connected
forthisadjustment.
l. Set2 adjustedtofull
C.
W.
2. Press
button 3 and
adjustR39for exactly
200mAon
the currentmeter
of the 1602 power
supply,
then
release
button 3.
fl,'
100v
METER
CAL
CURRENT
METER
CAL
Fig. 8. Location of CalibrationAdjustments
andFuses.
NOTE
If the unit has
just beenserviced,reconnect
the
load usedin Step2, to checkthe current limit.
Adjust LEVEL 12 for 50mA on the current
MCtEr.ROtAtE
B+ CURRENT SET C.C.W.UNtiI
"OVERLOAD" LIGHTS. Press button 3 to
check accuracy. If OVERLOAD DOES NOT
LIGHT, CURRENT LIMIT CIRCUIT IS BAD.
Also refer to NOTE under 4d, page 5.
FUSEREPLACEMENT
If thereis no power supplyoutput, and the POWERlamp
does
not light, check fuse Fl. If the POWERlamp lights,
but thereis no output from the main 400V supply,check
Fuse
F2.
If the POWER
lamplights, but there
isno I2.6VAC output
after
resetting
18 onthe 1602
front panel
check
F-3.
All fuses are3AG pigtail type, andlocationsshownin Fig.
8.
All fuses are accessible
by removingthe top cover.To do
this, remove3 screwsat the rear,
lift the top coverat the
rear,andslidethe front lip of the cover from theretaining
bosseson thefront panel.
l
LIMIT
I CAL
400v
MAX
OUTPUT
ADJ
I4

+
WARRANTY
SERVICE
INSTRUCTIONS
1. Referto the MAINTENANCE section
of your B& K-Precision
instruction
manual
for adjustments
that maybeapplicable
2. If the above-mentioned
procedures
do not correcttheproblem
you areexperiencing
with your unit, packit securely(preferably
in theorigihal
cartonor doubli-packed)l
Enclose
aletter describing
the problem
andinclude
four name
andaddress.
Deliver
to, or ship PREPAID ([IPS preferred) to the neaiestB & K-Precision
authorized
service
agency
(see
list enclosed
with unit).
If your list of authorizedB & K-Precision
service
agencies
has
been
misplaced,
contact
yourlocal
distributor
for thename
of yournearest
seivice
agency,
orwrite-to:
ServiceDeprtment
B & K-Precision
ProductGroup
DYNASCANCORPORATION
6460
West
Cortland
Street
Chicago,
Illinois 60635
LIMITED ONE.YEAR
WARRANTY
DYNASCAN CORPORATIONwarrantsto the originalpurchaser
that its B& K-PRECISION
product, and the component
parts
thereof,
will be freeirom defects
in workmanship
andmaterials
for aperiod
sf one
year
from thedate
of purchase.
DYNASCANwill, without charge,
repair
or replace,
at its optiondefective
product
or component
parts upon delivery to an authorized
B& K-PRECISION
service
contractor
-orthe factoryiervice
department,accompanied
by proof of thedate
of purchase
in theform of asalesreceipt.
To obtain warrantycoverage,
this product must be registered
by completing
and mailing the
enclosed
warranty
registration
cardto DYNASCAN,B & K-PRECISION,
646bWest
Cortland
Slreet.
chicago,
Illinois60635within fifteen(15days)
from thedateof purchase.
Exclusions:This warranty doesnot apply in the eventof misuse
or abuse
of theproduct or as
a
result of unauthorized alterations or repairs.It is void if the serialnumber is alterid. defacedor
removed.
DYNASCAN shall not be liable for any consequential
damages,
includingwithout limitation
damages
resulting
from loss
of use.Some
states
donot allowlimitati,on
of incidental
or consequential
damages,
so
theabove
limitation or exclusion
maynot applyto you.
This warrantygives
you specific
rightsandyou mayalsohave
otherrights
whichvaryfrom state
to state.
For your convenience
we suggest
you contactyour B& K-PRECISION
distributor,
whomaybe
authorizedto makerepairs
or can refer you to the nearestservice
contractor.If wairanty ,"rui".
cannotbe obtained
locally,please
send
theunit to B & K-PRECISION
Service
Department,
6460west
Cortland
Street,
Chicago,
Illinois60635,
properly
packaged
to avoid
damage
in shipment.

-\
DYNASCAN
COFlPOF|ATION
6460 West GorflondStreet
Chicogo,
lllinois60635
480.152-9-001G
o1980 o DYNASCAN
CORP.
PRINTED
IN U.S.A.