Allied Radio Knight-Kit KG-620 VTVM User manual

copyright 1956, 1963 Knight Brectronght Core., Mayivood. iHinois
4
a

Thank
You.
..
for your interest in Knight-Kits.
This Assembly Manual represents our many decades of ex-
perience in developing electronic kits which bring you out-
standing performance at dollar-saving prices... and with
maximum ease of construction.
As you go through the pages of this brochure, note how
carefully each stage of construction is explained—how
each diagram is magnified so that you almost have
the feeling a good instructor is working at your side!
Knight-Kit’s ‘do and check’’ method of kit-building insures
accurate and simple assembly. Although your final product may
represent a very complicated piece of electronic equipment,
you will proceed with ease and assurance, step-by-step... and
enjoy enormous satisfaction in your completed working unit.
Every Knight-Kit of your choice is available to you on the
Allied Credit Fund Plan—
« No Money Down
«24 Months To Pay
«Up To 50% Increased Buying Power
Your Knight-Kit purchase is backed with our exclusive and
iron-clad guarantee—you must be completely satisfied or your
purchase price is refunded!
It is always a pleasure to serve you.
A. D. Davis, President

ELECTRONIC VACUUM TUBE VOLTMETER KIT
FEATURES
* Push-Pull Balanced-Bridge Meter Circuit +» Positive and Negative DC Function
Assures Accuracy and Protection Switch Positions Eliminate Lead
Reversal
* Zero-Center Scale for Alignment of TV
and FM Discriminator Circuits
* Measures BOTH Peak-to-Peak and RMS, Transformer-Type Power Supply for Line
* 11-Megohm Input Resistance Minimizes
Circuit Loading—Gives True Readings
AC Voltages in 7 Ranges Each isolation and Operating Safety
* Single Zero-Adjustment Control for all + Calibrates Without Removing Cabinet
Functions and all Ranges « Film-Type 1% Precision Resistors
Outstanding in both performance and value. ... offering all the quality
that years of experience and research in instrument development can provide
... having all the modern, advanced features needed for all-around efficiency
of electronics servicing ... this is your Knight-Kit VTVM.
Provides entirely electronic, direct-reading measurement of AC voltage (BOTH
Peak-to-Peak and RMS values), DC voltage, decibels and resistance on a rugged,
highly legible, two-color 44%” full-view meter. Invaluable for signal tracing, for
alignment, for voltage and resistance measurements in AM/FM radios or tuners,
television and hi-fi sets, for checking frequency response, for continuity tests,
and for servicing electrical equipment.
Feature highlights include: film-type 1% precision resistors and multipliers;
low-leakage function and range switches; finest-grade printed circuit board;
3 separate test leads for AC-Ohms, DC, and Common; heavy-gauge steel case
with rugged panel: pilot light: transformer-operated power supply for line
isolation and safety; standard 1%-volt ‘‘C’’ battery; 200-microamp meter move-
ment; carrying strap; and premium-quality parts,
Circuitry boasts: push-pull balanced-bridge for maximum accuracy and meter
protection; DC polarity-reversing switching; 11-megohm input resistance to
reduce circuit loading to a minimum and assure true readings; zero-center
scale; direct-reading decibel scale; highly sensitive DC amplifier to allow
resistance measurements as high as 1000 megohms using only the 1% volt
battery — eliminating danger to delicate apparatus under test; single zero-
adjustment control for all functions and ranges; and calibration without removing
internal chassis from cabinet.
Always look to Knight-Kit, established leader in professional test equipment
design, for versatility, rugged construction, and proven dependability.

SPECIFICATIONS
DC Voltmeter:
RangeS..........00...000 cee 1.5, 5, 15, 50, 150, 500,
and 1500 volts full scale.
Input Resistance.............. 11 Megohms (1 Megohm
in probe) on all ranges.
Circult:. 3:4. gh akon Push- Pull balanced
bridge with 12AU7 twin
triode.
ACCULACY...... cece eee +3% full scale.
AC Voltmeter:
RMS Ranges................... 1.5, 5, 15, 50, 150, 500,
1500 volts full scale.
ACCULACY...0.. eee +5% full scale.
Peak-to-Peak Ranges......4, 14, 40, 140, 400, 1400,
4000 volts.
Ohmmeter:
Ranges... i.2c.ocacc eave: Center scale at 10 with
multipliers X 1, x 10,
x 100, x 1000, x 10K,
* 100K, x 1Meg.
Meter: 414” 200 »A movement.
Multipliers: 1% precision type.
12AU7, twin triode me-
ter bridge.
6AL5, twin diode full
wave rectifier.
Tube Complement:
110-125 volts, 60 cycles
AC,
Power Supply:
Battery: 1.5 volt “C” battery.
HOW TO BUILD THE KNIGHT VTVM
Your KNIGHT VTVM uses a printed circuit which
assures you that the VTVM will be an accurate, reli-
able test instrument regardless of age. A sheet of cop-
per is bonded to a sheet of phenolic. When the wiring
pattern has been determined, the unused portion of
the copper sheet is etched off leaving an exact dupli-
cation of the engineering prototype. Exact duplication
is one of the greatest advantages of printed circuits,
and prevents variation in wiring and performance
from instrument to instrument.
Your KNIGHT VTVM is all electronic. That is, the
bridge circuit is used for every measurement of DC
2
voltage, resistance, and AC voltage after rectification
by the full-wave rectifier.
The meter employed is an extremely stable, sensitive
200 microampere movement. The multipliers are 1%
precision type. Overall accuracy of the DC functions is
+3% of full scale reading, and +-5% on AC functions.
A wide choice of measurements is provided giving you
seven ranges on DC, AC, and resistance. Both RMS
and peak-to-peak AC voltages may be measured.
Your KNIGHT VTVM, through the use of the print-
ed circuit, saves a great deal of tedious wiring, assures
you of a finished instrument which compares closely
to the original engineering model, and provides you
with an instrument worth many times its low cost.
Before starting to build your KNIGHT VTVM,
check each part against the Parts List on page 23. If
you are unable to identify some of the parts by sight,
locate them on the pictorial diagrams. Capacitor and
resistor values, if not printed on the part, can be found
with the aid of the color code chart.
Hardware is listed in the last part of the Parts List.
To keep our kits at the lowest possible price, we fre-
quently weigh hardware rather than to count it.
Therefore, do not be concerned if more nuts and
machine screws, for example, are supplied than are
specified in the Parts List.
The only tools required for building your KNIGHT
VTVM are: Long-nose pliers, diagonal cutters, screw-
driver, set-screw driver, and a soldering iron.
Study the pictorial diagrams and note how the parts
are mounted. These pictorial diagrams show the actual
location of all parts and wiring. The schematic dia-
gram shows how the parts are connected electrically
and is helpful in understanding how the circuits work.
The step-by-step instructions were prepared by a
skilled technician while he was actually building the
KNIGHT VTVM. Therefore, they are the best and
fastest way of assembling this instrument. We suggest
that you read through the instructions before building
the VTVM. This will enable you to familiarize yourself
with the procedure and avoid possible errors. We
invite you to use the blank parentheses, ( ), before
each step to check it off after you have completed it.
Each step is clearly illustrated on an accompanying
line drawing. Some builders prefer to “cross out” each
wire and component on the drawings with a colored
pencil after it is installed. While an excellent way to
avoid mistakes, and highly recommended by us, this
procedure results in drawings that are difficult to re-
use. For this reason each wiring view is reproduced on
a separate, folded sheet of paper.
You are now ready to build your KNIGHT VTVM.

THIS KIT MUST BE PROPERLY SOLDERED!
USE ENOUGH HEAT
This is the main idea of good soldering. Apply enough heat
to the metal surfaces you are joining to make the solder
spread freely, until the contour (shape) of the connection
shows under the solder.
AN ELECTRONIC UNIT WILL NOT WORK... unless it
is properly soldered. Read these instructions carefully to
understand the basic ideas of good soldering.
Enough heat must be used so the solder can actually pene-
trate the metal surfaces, making an unbroken path over
which electricity can travel. You are not using enough heat
if the solder barely melts and forms a rounded ball of rough,
flaky solder.
Use the Right Soldering Tool
A soldering iron in the 40-100 watt range is recommended.
Any iron in this range with a clean, chisel-shaped tip will
supply the correct amount of heat to make a good solder
connection. You may also use a solder gun but make sure
the tip reaches full heat before you solder.
Keep the iron or gun tip brightly coated with solder, When
necessary, wipe the hot tip clean with a cloth. If you are
using an old tip, clean it before you start soldering. Use a
fine file or steel wool to expose the bright metal. Heat the
iron and immediately coat the tip with solder.
Use Only Rosin Core Solder
We supply the right kind of solder (rosin core solder). Do
not use any other kind of solder! Use of Acid Core Solder,
Paste, or lrons Cleaned on a Sal Ammoniac Block will ruin
any Electronic Unit and will Void the Guarantee.
1. Join bare metal to bare metal; insulation must be
removed. Make good mechanical connections and
keep resistor and capacitor leads as short as possible,
unless otherwise specified.
2. Coat the tip of a hot iron with solder. Then Firmly
Press the Flat Side of the Tip against the parts to be
soldered together. Keep the iron there while you...
3. Apply the solder between the metal to be soldered
and the iron tip. Use only enough solder to flow over
all surfaces of the connection, and all wires in the
connection. Remove the iron.
Do Not Move Parts Until the Solder Hardens. If you
accidentally move the wires as the solder is hardening,
apply your iron and reheat.
4.. Compare your soldering with the picture on this
page. You have a good connection if your solder has
flowed over all surfaces to be connected following the
shape of the surfaces. It should appear smooth and
bright and all wires in the connection should be well-
soldered,
You Have Not Used Enough Heat: If your connection
is rough and flaky-looking, or if the solder has formed
a round ball instead of spreading.
The difference between good soldering (enough heat)
and poor soldering (not enough heat) is just a few
extra seconds with a hot iron firmly applied.
REMEMBER, LARGER METAL SURFACES TAKE
A LONGER TIME TO HEAT.

SHOULDER
PIN JACK So WASHER
PIN JACK DETAIL
SCRAPE PAINT AWAY
FROM HOLE
SCRAPE PAINT AWAY
FROM HOLE
FIGURE
1.
MOUNTING
THE
PARTS
ON
THE
PANEL
:

MOUNTING THE PARTS ON THE PANEL
Before you begin mounting the parts, place a pad
or
a
soft
cloth
on
your
work
table
to
protect
the
finish
on the front panel.
SEE FIGURES 1 AND 2
(
)
Insert
the
short
flat
head
screw
through
the
hole
in
the
top
center
of
the
panel.
Place
an
external
lockwasher
over
the
screw.
Next
put
one
of
the
cable
clamps
over
the
screw.
Now,
put
on
an
in-
ternal
lockwasher
and
tighten
a
nut
over
it
very
securely.
See
Figure
2.
Bw
|
'
'
INTERNAL LOCKWASHER GQ
|
'CABINET MOUNTING CLIP
Sere CLAMP)
!
EXTERNAL LOCKWASHER
FIGURE
2.
HOW
TO
ASSEMBLE
THE
CABINET
CLAMP
( )
Mount
R-25,
10K
ohms
OHMS
ADJUST
potenti-
ometer,
in
the
large
hole
in
the
left
center
of
the
panel.
Use
two
nuts
to
mount
this
control
as
shown
in
Figure
3.
MOUNTING /
HOLES. ~%
SHE
=
$y)
))
4 controg » CONTREL
HEX NUTS (2)
FIGURE
3.
HOW
TO
MOUNT
A
CONTROL
(
)
Mount
R-27,
10K
ohm
ZERO
ADJUST
potenti-
ometer,
in
the
large
hole
in
the
right
center
of
the
panel,
in
the
same
manner.
(
)
Mount
the
‘pilot
light
socket
between
R-25
and
R-27.
The
bracket
must
be
positioned
as
shown
in
Figure
1,
but
must
not
touch
R-25.
(
)
Mount
J-1,
the
red
pin
jack,
in
the
lower
left
corner
of
the
panel.
Use
a
shouldered
fiber
washer
on
the
inside
of
the
panel
to
insulate
the
jack
from
the
panel.
Now,
tighten
a
nut
against
the
washer.
Refer
to
the
pin
jack
detail
in
the
upper
left
corner
of
Figure
1.
( ) Mount J-3, the black pin jack, in the lower right
corner of the panel in the same manner.
( ) Scrape the paint from the two holes as shown.
( ) Mount J-2, the chassis connector in the large
hole in the lower center of the panel. This con-
nector is supplied with a shouldered fiber wash-
er.
Take
this
washer
off
and
throw
it
away.
Place
the
flat
fiber
washer
over
the
small
threaded
end
of
the
connector.
Scrape
the
paint
from
around
this
hole
on
the
rear
of
the
panel.
Insert
the
small
threaded
end
through
the
hole
in
the
panel.
Place
the
solder
lug
and
the
flat
metal
washer
on
the
connector
and
tighten
the
nut securely. See Figure 4.
SOLDER LUG
FLAT
FIBER
WASHER
WASHER
FIGURE 4. HOW TO MOUNT THE
CHASSIS CONNECTOR
( ) Mount S§-1, the long triple wafer RANGE switch
in the hole in the lower left corner of the panel.
The long contact on the end wafer must be posi-
tioned as shown in Figure 1. The blank space on
the
wafer
near
the
shaft
end
must
be
toward
J-1.
Use
a
large
nut
and
a
lockwasher
on
the
inside
of
the
panel.
Fasten
it
securely
with
another
large
nut.
Place
a
large
knob
on
the
shaft.
Be
sure
the
line
on
the
knob
lines
up
ex-
actly
with
the
printed
dots
on
the
panel.
If
not,
rotate
S-1
so
the
scale
on
the
panel
and
the
line
on the knob correspond.
( )
Mount
S-2,
the
other
triple
wafer
FUNCTION
switch,
in
the
other
hole
on
the
right
of
the
panel.
Use
another
large
nut
and
lockwasher
in-
side
the
panel.
Use
a
large
nut
outside
the
panel.
Again
place
a
knob
on
the
shaft
and
be
sure
that
the
line
on
the
knob
lines
up
with
the
scale
on
the
panel.
You
have
finished
mounting
the
parts
on
the
panel
until
after
the
switches
are
wired.
WIRING
AND
SOLDERING
HINTS
How
well
a
piece
of
electronic
equipment
works
of-
ten
depends
on
the
quality
of
workmanship
used
in
its
construction.
It
is
for
this
reason
that
the
following
suggestions
are
made.
These
hints
are
mainly
for
the
beginner,
however,
even
experienced
persons
may
benefit
from
a
brief
review.

The
insulated
wire
furnished
with
this
kit
is
cut
to
length
and
the
ends
are
stripped.
Each
different
col-
ored
wire
is
a
different
length,
therefore,
be
sure
to
use
the
color
specified
in
each
of
the
wiring
steps.
A
long
piece
of
bare
wire
is
included.
Whenever
it
is
necessary
to
use
some
of
it,
the
exact
length
of
the
piece
required
is
given.
The
flexible
tubing
supplied
is
called
“spaghetti”.
Spaghetti
is
used
to
cover
the
bare
end
leads
of
some
of
the
components
and
portions
of
some
of
the
bare
wires
when
there
is
danger
they
will
touch
other
bare
wires
or
the
chassis.
The
proper
way
to
connect
a
wire
or
lead
to
a
solder
terminal
is
shown
in
Figure
5.
To
insure
a
good
me-
chanical
connection,
squeeze
the
wire
against
the
ter-
minal
with
your
long
nose
pliers
after
it
has
been
hooked
on.
Make
sure
the
wires,
leads,
and
terminals
are
clean
before
connecting
them.
If
necessary,
scrape
them
with
a
pocket
knife
until
any
foreign
substance,
such
as
wax,
is
removed.
Be
extremely
careful
not
to
nick
the
wire
with
the
knife,
or
it
may
break
when
it
is
bent.
FIGURE
5.
HOW
TO
CONNECT
A
WIRE
TO
A
TERMINAL
Unless
otherwise
stated,
all
the
leads
on
the
resis-
tors,
capacitors,
and
transformer
should
be
as
short
as
possible.
Figure
6
illustrates
the
best
way
to
con-
nect
a
component.
As
shown,
the
end
leads
should
be
pulled
through
the
terminals
so
that
the
parts
are
tightly
mounted.
After
a
lead
is
pulled
through
a
terminal,
bend
it
around
the
terminal
and
cut
off
the
excess
wire.
USE
ONLY
ROSIN
CORE
SOLDER
KITS
WIRED
WITH
ACID
CORE
SOLDER
OR
PASTE
FLUX
WILL
CORRODE
AND
WILL
NOT
WORK
LONG.
SUCH
KITS
ARE
NOT
ELIGIBLE
FOR
REPAIR
OR
SER-
VICE.
DO
NOT
USE
A
SAL
AMMONIAC
BLOCK
TO
CLEAN
YOUR
IRON.
IT
IS
VERY
CORROSIVE.
6
Before
soldering,
the
tip
of
your
soldering
iron
must
be
properly
tinned.
To
do
this,
clean
the
surfaces
of
the
tip
with
steel
wool,
or
a
fine
file,
until
the
bright
copper
surface
is
exposed.
Plug
the
iron
in
and
allow
it
to
heat
until
it
melts
solder.
Apply
solder
to
the
tip
until
it
is
well
covered
with
a
thin
coat.
Wipe
off
the
excess
solder
with
a
rag.
The
tip
should
now
be
“shiny”.
Re-tin
the
tip
whenever
it
becomes
covered
with
a
layer
of
scale
(flakes
of
gray
matter).
SOLDERING
WRONG WAY
TO SOLDER “fey,
}“t+——~- PROPERLY
SOLDERED
Roeten
A
SOLDER
FIGURE
6.
THE
BEST
WAY
TO
CONNECT
A
COMPONENT
Before
soldering
a
connection
be
sure
the
iron
is
hot
enough
to
melt
solder.
Preheat
the
CONNECTION
by
holding
the
tip
of
the
iron
against
the
joint
to
be
soldered.
After
the
joint
is
heated,
apply
solder
be-
tween
the
connection
and
the
iron
tip.
Use
only
enough
solder
to
fill
the
crevices
and
cover
all
of
the
wires
and
the
terminal.
Do
not
solder
any
connection
until
all
wires
have
been
connected
to
it.
After
you
have
soldered
a
connection,
push
any
insulation
or
spaghetti
as
close
to
the
connection
as
possible.
This
will
prevent
close
connections
from
touching
one
another
and
causing
a
short.
When
wiring
the
contacts
of
the
switches,
be
careful
not
to
bend
the
switch
contacts
which
will
reduce
the
spring
pressure
of
the
contacts.
If
the
flux
runs
out
around
the
contacts,
it
will
cause
a
leakage
path.
The
precision
resistors
furnished
with
your
VTVM
are
sensitive
to
heat.
When
you
make
a
solder
connec-
tion
close
to
the
body
of
one
of
these
resistors,
hold
the
lead
with
the
long
nose
pliers
between
the
body
and
the
connection
to
be
soldered.
The
jaws
of
the
pliers
will
conduct
the
heat
away
from
the
body
of
the
resistor.
You
are
now
ready
to
begin
wiring
your
KNIGHT
VTVM.
As
you
are
wiring,
we
would
like
you
to
keep
the
following
in
mind:
Do
your
best
to
position
the
parts
as
shown
in
the
wiring
diagrams,
and,
above
all,
USE
ONLY
ROSIN
CORE
SOLDER.
WIRING SWITCH S-1
§-1
is
the
three
wafer
switch
in
the
lower
left
corner
of
the
panel.
The
open
space
between
two
of
the
ter-
minals,
on
the
wafer
nearer
the
shaft
end,
is
used
as
the
reference
point
for
numbering
the
terminals.

SEE
FIGURE
7.
(
)
Connect,
but
do
not
solder,
one
end
of
R-16,
10K
ohm
resistor,
to
terminal
13.
Insert
the
other
CAUTION:
The
precision
resistors
mounted
on
the
end
through
a
1%
inch
length
of
spaghetti.
Con-
range switch
S-1
must
not
touch each
other,
nearby
nect,
but do
not
solder, it
to
terminal
17.
ee
a
the
a
nie
ae
alone
utes
( )
Connect,
but
do
not
solder,
one
end
of
R-20,
90K
ee
ae
dl
s
Pars
He
pita
a
a
Uae
Rent
ie
anes
ohm
resistor,
to
terminal
14.
Connect,
but
do
aeauansas
“pail Seeacsee
age
A
Se Re
eee
not
solder,
the
other end
to terminal
25.
resistors,
keep the
leads
short,
as
shown
in
the
illus-
tration.
Clip
off
excess
lead
lengths.
( )
Connect,
but
do
not
solder,
one
end
of
a
2
inch
( )
Connect,
but
do
not
solder,
one
end
of
R-2,
280K
esata
a
Denne.
14.
Solder
the
other
end
ohm
resistor,
to
terminal
1
of
S-1.
Connect,
but
5
do
not
solder,
the
other
end
to
terminal
4
of
S-1.
(
)
Solder
one
end
of
R-21,
9K
ohm
resistor
to
ter-
Position
R-2
as
shown
in
Figure
7.
minal
14.
Connect,
but
do
not
solder,
the
other
( )
Connect,
but
do
not
solder,
one
end
of
R-3, 900K
end to
terminal
27.
;
ohm,
1
watt, resistor,
to terminal
1.
Connect,
( )
Connect,
but do
not
solder,
one
end of
R-22,
900
but
do
not
solder,
the
other
end
to terminal
6.
ohm
resistor,
to
terminal
16.
Solder
the
other
Position
R-3
as
shown in Figure
7.
end
to
terminal
27.
( )
Solder
one
end
of
a
2
inch
bare wire
to
terminal
( )
Connect,
but
do
not
solder,
one end
of a
2
inch
1.
Insert the
other
end
through a
114
inch
length
bare
wire
to terminal
16.
Solder the
other
end
of
spaghetti.
Solder
it
to terminal
5.
to
terminal
28.
( )
Solder
one end
of R-1,
130K
ohm
resistor,
to
( )
Solder one
end of
R-23,
90
ohm
resistor,
to ter-
terminal
4.
Connect,
but
do not
solder,
the
other
minal 16.
Connect,
but
do not
solder,
the
other
end to
terminal
13.
end
to
terminal
29.
VL) j
ay
enna
eT
RB
ni
ie
Ss
31
30 29 28
27 26
25
29
y
e
$-10
(
¥
28,
33
SOLDER
TO
TERMINAL
30
27
34
i
ca
26
35
4a
Wa
|go
“er
g
Zi
8 ©
Sag fs
RANGE
SWITCH
q
a
a
(END
VIEW
S-1D}
Psy
fm
“
a
g
os
&
«
& cl
fife
&
Wy
\
|
L\)
a
UT
SOLDER
TO
TERMINAL 24
0
OF
S-fC
$-1C: 18:
17
‘
J
¥
13
$-1C
16
15
14
—Tr-1
10K
R-l
130K
|
R-3
900K
1
WATT me
s-A—“g
,
td
0
3
'
5 4
3
roc]r-2
280k|_
BLANK
SPACE
MUST
BE
TOWARD
LOWER
LEFT
CORNER
OF PANEL
LEFT
SIDE
RIGHT
SIDE
FIGURE 7. HOW TO WIRE THE RANGE SWITCH

FIGURE
8.
HOW
TO
WIRE
THE
PANEL
.
R-24
)
va!
a
(2)
32
30
29
28
27
26
25
by
2
28
33
SOLDER
TO
TERMINAL
30
27
34
OF
S-ID
26
35
25
36
RANGE
SWITCH
(END
VIEW
S-1D)
SOLDER
TO
TERMINAL
24
OF
S-IC
S-1C
S-1B
BLANK
SPACE
MUST
BE
TOWARD
LOWER
LEFT
CORNER
OF
PANEL
LEFT
SIDE
RIGHT
SIDE
FIGURE
7
HOW
TO
WIRE
THE
RANGE
SWITCH

pees
area
om
ae
G3alslIdWIS
ONY
QGSAQNVdxX3
NMOHS 3YY SSHOLIMS
3LON

SORES OEE SS
Solder
one
end
of
R-15,
20K
ohm
resistor,
to
ter-
minal
17.
Connect,
but
do
not
solder,
the
other
end
to
terminal
30.
Solder
one
end
of
a
2
inch
red
wire
to
terminal
18.
Connect,
but
do
not
solder,
the
other
end
to
terminal
30.
Pass
one
end
of
R-14,
70K
ohm
resistor
through
terminal
19
and
connect
it
to
terminal
7.
Solder
terminal
7,
but
do
not
solder
terminal
19.
Solder
the
other
end
of
R-14
to
terminal
30.
Solder
one
end
of
R-13,
200K
ohm
resistor,
to
terminal
19.
Connect,
but
do
not
solder,
the
other
end
to
terminal
32.
Pass
one
end
of
a
3
inch
hare
wire
through
ter-
minal
20
and
connect
it
to
terminal
8.
Solder
both
terminals
8
and
20.
Connect,
but
do
not
solder,
the
other
end
to
terminal
32.
Connect,
but
do
not
solder,
one
end
of
R-12,
700K
ohm
resistor,
to
terminal
21.
Solder
the
other
end
to
terminal
32.
Pass
one
end
of
R-11,
2
Megohm
resistor,
through
terminal
21
and
connect
it
to
terminal
9.
Solder
both
connections.
Connect,
but
do
not
solder,
the
other
end
to
terminal
34.
Pass
one
end
of
a
3
inch
bare
wire
through
ter-
minal
22
and
connect
it
to
terminal
10.
Solder
poth
connections.
Connect,
but
do
not
solder,
the
other
end
to
terminal
34.
Pass
one
end
of
R-10,
7
Megohm,
1
watt,
resis-
tor,
through
terminal
23,
and
connect
it
to
ter-
minal
11.
Solder
terminal
23,
but
do
not
solder
terminal
11.
Solder
the
other
end
to
terminal
34.
Connect,
but
do
not
solder,
one
end
of
R-17,
9
Megohm,
1
watt
resistor,
to
terminal
24.
Solder
the
other
end
to
terminal
35.
Connect,
but
do
not
solder,
one
end
of
a
red
wire
to
terminal
24.
Solder
the
other
end
to
terminal
36.
Solder
one
end
of
R-19,
900K
ohm
resistor,
to
terminal
24.
Solder
the
other
end
to
terminal
25.
Solder
one
end
of
R-24,
the
9.1
ohm
wirewound
resistor
marked
with
the
color
bands
white,
brown,
gold,
and
gold,
to
terminal
29.
Connect,
but
do
not
solder,
the
other
end
to
terminal
31.
You
have
finished
mounting
the
precision
resistors.
VERY
CAREFULLY
CHECK
EACH
CONNECTION
MADE
ON
§-1.
Compare
your
completed
switch
with
Figure
7.
A
single
error
here
will
keep
your
kit
from
operating
properly.
HOW
TO
WIRE
THE
PANEL
SEE FIGURE 8.
(
)
Solder
one
end
of
a
green
wire
to
terminal
1
on
the
pilot
light
socket.
Connect,
but
do
not
sol-
der,
the
other
end
to
the
solder
lug
under
the
chassis
connector
nut.
Solder
one
end
of
an
orange
wire
to
terminal
13
on
§-1.
Connect,
but
do
not
solder,
the
other
end
to
the
solder
lug.
(
ie
Solder
one
end
of
another
orange
wire
to
the
terminal
on
J-3,
the
common
jack.
Solder
the
other
end
to
the
solder
lug.
(
)
Pass
one
end
of
a
red
wire
through
the
chassis
connector.
Solder
it
to
the
eyelet
in
the
center
of
the
connector.
Insert
the
other
end
through
a
11%
inch
length
of
the
large
spaghetti.
Force
the
spaghetti
down
against
the
soldered
eyelet
connection.
Solder
the
other
end
of
the
red
wire
to
terminal
1
of
S-2.
(_)
Insert
each
end
lead
of
C-2,
.01
MFD
paper
ca-
pacitor,
through
a
114
inch
length
of
small
spa-
ghetti.
Solder
the
lead
from
the
banded
end
to
terminal
9
of
S-2.
Solder
the
other
lead
to
termi-
nal
6
of
S-1.
Position
C-2
between
J-2
and
S-2A.
(
)
Solder
one
end
of
a
red
wire
to
terminal
11
of
S-1.
Solder
the
other
end
to
terminal
2
of
S-2.
( )
Solder
one
end
of
a
yellow
wire
to
terminal
12
of
8-1.
Solder
the
other
end
to
terminal
6
of
S-2.
( )
Insert
a
green
wire
through
a
414
inch
length
of
the
large
spaghetti.
Solder
one
end
to
J-1.
Sol-
der
the
other
end
to
terminal
8
of
S-2.
(
)
Solder
one
end
of
a
green
wire
to
terminal
3
of
S-1.
Connect,
but
do
not
solder,
the
other
end
to
terminal
15
of
S-2.
(
)
Solder
one
end
of
a
yellow
wire
to
terminal
1
of
R-25.
Solder
the
other
end
to
terminal
11
of
§-2.
(
)
Solder
one
end
of
a
blue
wire
to
terminal
2
of
R-25.
Connect,
but
do
not
solder,
the
other
end
to
terminal
1
of
R-27.
(_)
Solder
one
end
of
a
green
wire
to
terminal
33
of
S-1.
Solder
the
other
end
to
terminal
7
of
8-2.
(
)
Solder
one
end
of
a
red
wire
to
terminal
12
of
S-2.
Connect,
but
do
not
solder,
the
other
end
to
terminal
3
of
R-27.
(
)
Solder
one
end
of
a
green
wire
to
terminal
15
of
8-1.
Solder
the
other
end
to
terminal
4
of
S-2.
SEE FIGURE 9.
(
)
Be
sure
the
paint
is
scraped
from
around
the
lower
right
meter
mounting
hole
on
the
rear
of
the
panel.
(
)
Insert
the
two
6-32
x
2”
screws
through
the
holes
in
the
panel
where
shown.
These
screws
are
held
in
place
by
the
meter
which
is
mounted
in
the
next
step.
(
)
Mount
the
meter
from
the
front
of
the
panel
over
the
heads
of
the
two
screws
set
in
the
panel.
Tighten
one
of
the
nuts
supplied
with
the
meter
over
each
of
the
two
top
screws
and
the
lower
left
screw.
Do
not
tighten
them
too
securely.
Place
an
internal
tooth
lockwasher
and
the
other
cable
clamp
over
the
lower
right
screw.
Now,
tighten
a
nut
over
the
screw.
The
other
four
nuts
supplied
with
the
meter
are
used
to
mount
the
printed
circuit
board.
NOTE:
If
the
meter
was
supplied
with
a
shorting
|
wire
between
the
meter
terminals,
remove
this
wire

( ) Solder one end of a blue wire to terminal 14 of the positive meter post.
oa solder he ean fouthe solder. 1Ue On ( ) Solder one end of another violet wire to terminal
the negative meter post, 2 of the pilot light socket. The other end will be
( ) Solder one end of a violet wire to terminal 10 of connected to the printed circuit later.
S-2. Solder the other end to the solder lug on ( ) Insert the pilot lamp into its socket.
NOTE
SWITCHES ARE SHOWN EXPANDED AND SIMPLIFIED. THEREFORE,
WIRE LENGTHS APPEAR LONGER THAN ACTUAL SIZE.
<——o
FIGURE 8. HOW TO WIRE THE PANEL

6-32X2" SCREW
peerrerry
ete rrcrreererorRED
meee pepbpprrerstsy
AS
PFeees
MUU
a
a ee
SOOT
Sean pENCI Reon TEE
SRN
[sce
(TO
BE
MOUNTED
LATER)
nut SQ
CABLE CLAMP
INTERNAL LOCKWASHER

ASSEMBLING THE PRINTED CIRCUIT BOARD
You are ready to mount the parts on the printed
circuit board. Examine it. One side shows the out-
line and value of each part to be mounted. That is,
the capacitors, resistors, the transformer, the battery,
etc., are pictured in their exact location.
The following procedure assures well soldered con-
nections on the printed circuit board. Study it.
1. INSERT the wire leads of the parts through the
holes as shown in Figure 11.
2. BEND LEADS FLAT against the foil side of the
board so the part is held securely in place.
3. SOLDER EACH LEAD of each part (after all
parts are mounted) right at the hole in the metal
foil where the lead comes through. Be sure you
heat the connection until the solder runs and
spreads.
4. CUT OFF EACH LEAD as close as possible to the
board. Inspect each lead after cutting it off to be
sure it does not short across the bakelite from one
foil conductor to another. This would cause a
short and your VTVM won't work.
If a soldered connection should have a dull appear-
ance it is not a good solder connection. Using more
solder, again solder the connection. Do not use so
much solder that it runs off the printed foil wiring
onto the board and touches, another foil conductor.
This may cause an intermittent or a short between
connection points.
Before you solder the tabs of the tube sockets to
the metal foil, insert the tubes in the sockets. When
you solder the tabs of the tube sockets to the metal
foil, heat the tube socket tab until the solder runs
down onto the metal foil and spreads.
After you have soldered all the connections on the
printed circuit board, but before you put in the cable,
examine the metal foil side of the board carefully.
Again be sure no solder or cut-off lead touches any
foil conductor except the one to which it is soldered.
Also, be sure the tabs of the controls have not been
bent so much that they touch any other conductor.
If the flux from the solder has run out around the
connections that is all right. The flux is not conductive.
SEE FIGURE 11.
( ) Mount the 9-pin miniature socket for V-2, the
12AU7, from the screened side of the board.
This socket can be mounted only one way. Line
up the notch in the socket with the half-moon
shaped notch in the board. Put the 12AU7 in the
socket. Solder one end of a 1 inch bare wire to
pin 1. Solder the other end to pin 6. The wire
must not touch the bottom of the socket. Solder
all pins to the board. See Figure 10.
( ) Mount the 7-pin miniature socket for V-1, the
6AL5. Put the 6AL5 in the socket. Solder all
pins. Then remove both tubes and place them
back in their boxes.
( ) Mount R-34, 10,000 ohms AC Balance potenti-
ometer, from the screened side of the board. The
three terminals must be toward the left edge of
the board. Bend the two large, flat terminals
out slightly so the potentiometer is held firmly.
Do not bend either flat terminal so much that it
touches another foil conductor.
NOTE.-DO NOT ALLOW
JUMPER WIRE TO TOUCH
BOTTOM OF SOCKET.
FIGURE 10. JUMPER WIRING ON V-2.
Solder
each
terminal
and
also
the
two
large
flat
terminals.
(
)
Mount
R-29,
10,000
ohms
DC
Calibration
poten-
tiometer
in
the
same
manner.
Solder
the
large
flat
terminals
and
the
two
small
terminals.
(
)
Mount
R-26,
10,000
ohms
AC
Calibration
po-
tentiometer
in
the
same
manner
with
the
three
terminals
toward
the
terminals
of
R-29.
Solder
the
three
terminals
which
go
into
the
printed
wiring.
( )
Mount
CR-1,
the
rectifier,
by
inserting
the
two
terminals
through
the
holes
in
the
upper
left
corner
of
the
board.
The
positive
side
must
be
toward
the
right.
Bend
the
two
terminals
slight-
ly
to
hold
CR-1
firmly.
Solder
both
terminals.
(
)
Mount
C-6,
the
20
MFD,
200V
electrolytic
filter
capacitor,
with
the
“+”
end
next
to
the
recti-
fier.
Solder
both
leads.
SEE FIGURES 11 AND 12.
( ) Mount the battery bracket as shown in Figure
12. Insert the 6-32 x 5/16” machine screw
through the battery retaining clip through the
center hole in the battery bracket, through a flat
fiber washer, and through the hole in the printed
circuit board. Tighten a nut onto the screw. Use
the thin screw through the hole in the end of
the bracket near T-1, and through the circuit
board. Place a small flat metal washer over the
screw on the printed circuit wiring side of the
board and tighten a nut over the screw.
WwW

B-1
BATTERY
FIGURE
11.
MOUNTING
THE
PARTS
ON
THE
PRINTED
CIRCUIT
BOARD
You
are
now
ready
to
mount
the
resistors
and
capacitors
on
the
printed
circuit
board.
(
)
Mount
R-9,
3.3
Megohm
resistor
(orange,
orange,
green)
as
shown
in
Figure
11.
Mount
C-4,
.005
MFD
disc
capacitor.
Mount
R-18,
150K
ohm
resistor
(brown,
green,
yellow).
Mount
R-28,
150K
ohm
resistor
(brown,
green,
yellow).
Mount
R-33,
22K
ohm
resistor
(red,
red,
orange).
Mount
R-31,
220K
ohm
resistor
(red,
red,
yel-
low).
Mount
R-32,
100
ohm
resistor
(brown,
black,
brown).
(
(
PONS
)
)
al
)
)
Mount
C-5,
.005
MFD
disc
capacitor.
Mount
R-30,
10
Megohm
resistor
(brown,
black,
blue).
Mount
R-36,
2.2
ohm
resistor
(red,
red,
gold,
gold).
Mount
R-5,
22
Megohm
resistor
(red,
red,
blue).
Mount
R-6,
22
Megohm
resistor
(red,
red,
blue).
Mount
R-7,
22
Megohm
resistor
(red,
red,
blue).
Mount
R-8,
22
Megohm
resistor
(red,
red,
blue).
Mount
R-35,
10K
ohm
resistor
(brown,
black,
orange).
Mount
C-1,
.02
MFD
disc
capacitor.
Mount
R-4,
22
Megohm
resistor
(red,
red,
blue).

MOUNTING BRACKET:
FIBER WASHER
(3)

‘el AYNSIS
J317€aV9 3HL ONILOANNOD
ce
Oe
oe
a
rae
WALA LH9SIN»

AN igi alata ican maa aaa
( )
Mount C-3, .02 MFD disc capacitor. Note that
the leads of this capacitor must be positioned
so that they clear the hole for mounting the
printed circuit to the panel.
Turn the circuit board over and solder each con-
nection. Remember to use a small iron and the
rosin-core solder supplied. Be sure the connec-
tion where R-18, R-28, and R-31 join is well
soldered. Cut off each end lead close to the
soldered connection.
FINAL WIRING
You are now ready to prepare the cable and do the
final wiring on your VTVM.
SEE FIGURE 13.
(
NNN
)
~
—
~—
eee
Carefully remove 414 inches of the outer insula-
tion from one end of the cable. Be very careful
not to cut the insulation of any of the wires.
Now, trim the wires to the following lengths:
Orange: Leave it the full 414 inches.
Green: 1”
Yellow: 1”
Red: 1144”
Violet: 13,”
Black: 2354”
Brown: 24,”
White: 314”
Blue: 414”
Remove 14 inch of insulation from the end of
each wire. Coat each end with solder.
Solder the black wire to the terminal on the bat-
tery bracket marked + Bat. This wire does not
go through the printed circuit board.
Insert each of the other wires into the hole in
the board marked with the corresponding color.
Solder each on the printed wiring side of the
board.
Remove 334” of the outer insulation from the
other end of the cable. Trim each wire as fol-
lows:
Red: Leave it the full 334”
White: 234”
Brown: 214”
Violet: 114”
Yellow: 234,”
Blue: 3”
Green: 334”
Orange: 2”
Black: 3”
Remove 1,” of insulation from the end of each
wire. Coat each end with solder.
Solder the violet wire to terminal 5 of S-2.
Solder the brown wire to terminal 3 of R-27.
Solder the white wire to terminal 2 of R-27.
Solder the red wire to terminal 1 of R-27.
Solder the yellow wire to terminal 13 of S-2.
BATTERY
RETAINING CLIP
SMALL
en ie oe a
wee
*— PRINTED CIRCUIT
BOARD
SMALL
|
I
i
2) ———-NUT
|
i
i
Solder the blue wire to terminal 15 of S-2.
Solder the green wire to terminal 16 of S-2.
Solder the orange wire to terminal 3 of S-2.
Solder the black wire to terminal 31 of S-1.
Solder
the
violet
wire
from
terminal
2
of
the
pilot
light
socket
to
PILOT
LIGHT
on
the
print-
ed
circuit
board.
Bring
this
wire
over
the
screen-
ed
side
of
the
board.
Put one of the spacers over each of the six
mounting screws.
Place three of the large fiber washers over the
screw shown.
Place the mounting bracket over this screw and
the top right meter mounting screw.
Place four of the large fiber washers over the
screw shown.
SEE FIGURE 14
( )
The
printed
circuit
board
will
be
mounted
on
six
mounting
screws.
First
place
a
large
fiber
wash-
er
on
the
single
screw
in
the
corner
of
the
panel
(upper
left
corner
in
Figure
14).
Then
mount
the
board
on
the
six
screws.
Place
another
large
fiber
washer
on
top
of
the
board,
over
the
same
corner
screw.
Secure
the
board
with
a
split
wash-
er
and
nut
on
each
of
the
four
screws,
as
shown
in
Figure
14.
Trim
the
leads
of
T-1,
the
power
transformer
to
the
following
lengths:
The
black
lead
toward
the
top
right
corner
to
114”,
The
other
black
lead
to
6”.
Both
green
leads
to
114”.
Both
red
leads
to
2”.
13

FIGURE
13.
HOW
TO
CONNECT
THE
CABLE
(
14
FROM TERMINAL 2 ON PILOT LIGHT SOCKET
SWITCHES
AND
CABLE
ARE
SHOWN
EXPANDED
AND
SIMPLIFIED.
THERE-
FORE,
WIRE
LENGTHS
APPEAR
LONGER
THAN
ACTUAL
SIZE.
~
PURPLE} go
NOTE
Remove
the
insulation
from
¥,”
of
the
end
of
each
lead.
Hold
the
lead
with
pliers
close
to
the
transformer
as
you
remove
the
insulation.
Coat
the
stripped
end
of
each
lead
with
solder.
Mount
T-1
on the
remaining
two
mounting
screws,
with
the
leads
positioned
as
shown.
Place
three
large
fiber
washers
under
the
mounting
tab
shown
and
fasten
the
transformer
with
two
split
washers
and
nuts.
)
Connect
the
leads
of
T-1
as
follows:
Solder
the
short
black
lead
in
the
hole
marked
MOUNTING BRACKET,
BLACK PRI.
Solder
the
long
black
lead
to
terminal
18
of
S-2.
Solder
the
green
leads
into
the
holes
marked
G.
:
Solder
the
red
leads
into
the
holes
marked
R.
|
(
)
Slide
the
bare
ends
of
the
line
cord
under
the
:
cable
clamp.
Tie
a
knot
in
the
cord
5”
from
the
|
bare
ends.
Split
the
cord
back
to
the
knot.
Solder
one
wire
in
the
hole
marked
LINE
on
the.
board.
Cut
214”
of
the
other
wire.
Solder
it
to
terminal
17
of
S-2.
|
|