HP 400E Service manual

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MODEL 400E/EL
AC VOLTMETER
Serials Prefixed: 532, 536
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PRELIMINARY
OPERATING AND SERVICE MANUAL
MODEL 400E/EL
AC VOLTMETER
Serials Prefixed: 532, 536
Copyright Hewlett-Packard Company 1965
P.O. Box 301, Loveland, Colorado, 80537 U.S.A.

Model
Sectio
I
Sectio
II
Sectio
Til
Sectio
IV
Sectio
400E/EL
Table
of
Contents
TABLE OF CONTENTS
n Page
GENERAL
INFORMATION
.......-62
2-2
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1-1
Je.
“DESETIPLION.
“ee
aos
iS.
eS
,
wo
eA
LS.
BSE
ee
wR
1-1
1-4.
Instrument
and
Manual
Identification
............
1-1
n
Page
INSTALLATION
|.)
dase
6
od.
BSS
Bre
YR
RO
ww
aes
2-1
Dat.
ANEPOOMCHON:
<<
a
&
Swi
Gee
ee
Se
Se
Se
Se
ae
Se
2-1
2-3.
Initial
Inspection.
.: «6
2
6
&
heh
ee
eG
2-1
2-5.
Power
Requirements
...
2...
2.
ee
tee
eee
ee
es
2-1
2-7.
Grounding
Requirements
........-2+4
eee
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2-1
2210.
Installation.
cS)
e-
se
se
Be
a
Be
sh
Se
Sis
we
ee
ay
2-1
2-12
Bench
Mounting
«206
se ee
ee
6
wee
ew
ee
2-1
2-14.
Rack
Mounting:
=.
©
3)
heise
sai
bs
ew
we
SEE
Rs
2-2
2-16.
Combination
Mounting
.........+4-+
252
eee
2-2
2-18.
Repackaging
for
Shipment
.....
2...
2+
ee
eeeee
2-2
n Page
OPERATING
INSTRUCTIONS
.......6+2-0+60022ee88
8-8
3-1
S23.
Introduction:
-3-
4G.
6
4
Bo
a
atte
ewes!
W
wee
2
3-1
3-4.
Location
of
Controls
and
Indicators
............
3-1
3-6. Operating Instructions ...... 2.2. eee ee ee eee 3-1
3-7.
Standard
400
B/E
DL.
-x.4.
©
s
«Sok
Gow
&
Nee
A
ae
6
3-1
3-12.
A400B
with
Option
01.
.
2.4
6.8
eee
ee
es
3-5
3-14. 400E/EL with Option02 ..........-+.00086- 3-7
3-17. 400E/EL with Option03 ..........6.220868- 3-7
n Page
THEORY OF OPERATION | “ics-a° dy 9 Gy eeceoee use. ee Se mee 4-1
AQT.
(General
io
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0
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4-1
4-6. Input Attenuator (See Schematic, Figure 6-1) ..... 4-1
4-8. Impedance Converter ... 1... ee ee eee eevee 4-1
4-11. Metér Amplifier o5-c-6:. 4 4% BeOS SE ER ee Soars 4-2
4-14. Meter Bridvte: tase go OS ee ee, oe A 4-2
4-17. AC Output-Citcult: <0 s9-e eve 68 See eee ee eG 4-2
4-19.
Power
Supply:
wx.
6-
e658
Gis:
Be
ea
ae,
SE
4-2
n Page
MAINTENANCE: so-55-3. 4.4 2 eck oe ed Be ee oe ee we 5-1
Ba 1s \ Int¥Oduetion® y.6..x se S.4ivea 8 OS Gow hel Ge Ae oe? he as 5-1
5-3. Required Equipment ..... 2... eee eee ee eens 5-1
5-5. Mechanical Zero Adjust (400E Only) ............ 5-1
5-7,.
Performance
Checks
«2.606
«6
6
Riek
ke
koe
Be
ae
eG
5-1
5-9. Accuracy and Frequency Response Test ....... 5-1
5-19. Input Impedance Check ...........2.2.20808. 5-8
5-24. Alignment and Calibration Procedure ........... 5-9
5-26. Cover Removal sé 2-4 eG Se Se OK A AO RES 5-9
ili

Table of Contents
TABLE OF CONTENTS (Cont'd)
Section
V MAINTENANCE (Cont'd)
5-29. Bias’AQist. .. 2 a8 2060s a5: 4 ecm eS
5-31. AC Output Zero ..........-..
5-33. CaliDFation: 2:4.°45.4 06 +5. } ake Sea wee
5-36. Troubleshooting ............4..-.
5-40. Power Supply 2.4: 4.40 44% 4 ees
5-42. Amplifiers «<6 4.494. ee 3 el oud %
5-45. AC Output Circuit) ob eo me Pa ey
Section
VI CIRCUIT DIAGRAMS ............e8.+e-.
6-1. Introduction ..............0e8e8-4
Section
VII REPLACEABLE PARTS .............
7-1. Imtroduction ..........6+4-+e5+80848-8
7-4. Ordering Information ............
7-6. Non-Listed Parts .............-.
Model 400E/EL

models
OE/400EL
AC VOLTMETERS ..
PACKARD
TECHNICAL DATA 12 AUG 65
li
fT
‘Ap
&
EWLETT |
goot AC voLTMeTet :
ci) peer PACKARD 9
“INDIVIDUALLY
~TAUT B
‘ SOLID. STATE.
i P. O. Box 301, Loveland, Colorado, 80537, Tel. [phone]
® Europe: 54 Route Des Acacias, Geneva, Switzerland, Cable: “HEWPACKSA" Tel. [phone]

Page 2
DESCRIPTION
The @ 400E/EL Solid-State AC Voltmeters are ruggedly
built solid-state precision instruments for measuring ac
voltages from 1 millivolt to 300 v rms full scale. They
cover a frequency range from 10 cps to 10 mc and have
constant 10 megohm input resistance on all ranges. Input
capacity is 24 pf on the 1 mv to 1 volt range and 9 pf on
the 3 vole to 300 volt range. The instruments are simple to
operate and give direct voltage and dbm readings.
These ac voltmeters have exceptional long-term stability
because their calibration is not dependent on active com-
ponent parameters which are subject to aging. The 400E/
EL may also be used as stable, high-gain ac amplifiers or
ac-to-de converters.
The 400E has all the characteristics mentioned above
with 1% of reading accuracy on a 4-1/2” mirror-backed
taut-band meter. The meter scale is individually calibrated
for its particular movement with 100 divisions to give an
added measure of readability.
The 400 EL has all the characteristics above with 1% of
reading accuracy on a linear 12 db logarithmic scale. This
meter is also individually calibrated with 120 divisions and
is ideal for db measurements.
The specifications in the chart on the next page show
these compact, lightweight, solid-state voltmeters will give
premium performance at an economical price.
CIRCUIT DESCRIPTION
The Model 400E/EL AC voltmeters use high-gain am-
plifiers having high stability and wide bandwidth. The
solid-state metering circuit is stabilized by an overall feed-
back loop to provide maximum stability. The impedance
converter circuit also uses a large amount of overall feed-
back. These features ensure a high degree of accuracy in-
dependent of line voltage changes or other external effects.
AC-to-DC CONVERTER
The Models 400E/EL provide a dc output (1 volt dc
for full scale meter deflection) proportional to meter de-
flection which can be used to drive a potentiometer or
galvanometer recorder. This dc output is available at the
rear panel of the instrument which is illustrated in figure
1.
Figure |: External Battery Terminals, DC Recorder
Output Terminals and AC Amplifier Terminals
Model 400E/EL
HIGH GAIN AMPLIFIER
Additionally,
the
400E
and
400EL
provide
a
stable
low
distortion,
high-gain,
wideband
ac
amplifier
with
a
50-ohm
output
impedance.
Frequency
response
is
from
10
cps
to
10
mc.
The
ac
output
is
150
mv
rms
for
full
scale
meter
deflection
on
all
ranges
except
on
the
1
mv
range
which
is
105
mv.
LOGARITHMIC MODEL 400EL
The
@
400EL
is
designed
for
greater
resolution
in
db
measurements.
This
instrument
is
useful
for
acoustical
and
communications
applications.
It
incorporates
an
@
taut-
band
mirror-backed
logarithmic
meter
movement.
For
ut-
most
accuracy,
the
meter
scale
is
individually
calibrated,
using
the
new
@
logarithmic
meter
calibrator,
The
meter
scale
provides
maximum
readability
and
+1%
of
reading
accuracy
on
the
upper
half
of
the
scale
and
+1.5%
of
read-
ing
accuracy
on
the
lower
half
scale.
The
decibel
scale
is
more
than
4-3/8”
long,
and
voltage
scales
spread
across
the
full
length.
A
range
switch
changes
sensitivity
in
10
db
steps
which,
combined
with
the
12
db
scale,
provides
the
overlap
desirable
in
decibel
level
measurements.
EASY TO USE
A
front
panel
range
switch
which
changes
sensitivity
in
10
db
steps,
combined
with
the
db
calibration
of
the
me-
ter,
permits
reading
of
dbm
directly
without
calibration
or
conversion
from
—72
to
+52
dbm
(0
dbm=1
milliwatt
into
600
ohms).
In
addition,
the
10
db
range
spacing
pro-
vides
2
voltage
scales
so
that
readings
are
always
greater
than
one-third
full
scale.
Consequently,
the
highest
possi-
ble
readability
and
accuracy
are
provided.
OPTIONS
Special
db-measuring
option—The
Model
400E
reads
directly
in
volts
and
db,
with
the
voltage
scale
uppermost.
The
Model
400E
(Option
01.)
with
db
scale
uppermost
is
recommended
for
greater
resolution
in
db
measurements.
Refer
to
figure
2.
1 MW 6000
DeciBELS gt a
VOLTS
HEWLETT PACKARD
Figure 2: Meter face on Model 400E (Option O1).

Model 400E/EL Page 3
Relative signal reading option—Available on special
order, the 400E/EL (Option 02.) provides a front-panel
relative measurement control allowing a 3 db reduction in
sensitivity on each calibration range. This feature enables
the user to set the meter to a convenient level (such as 0
db) for relative measurements. The control is detented in
the absolute position to disconnect the relative measuring weciais
circuitry and to ensure calibration accuracy. d tun ena
BEWLETT Gp racanee
Constant Input Capacity Option—Available on special
order, the 400E,EL (Option:03) provides constant input
capacity (28 pf) on all ranges and 10 megohms input
resistance.
y ABSOLUTE.”
Figure
3:
Option
02
(400E
and
EL)
provides
relative
or
absolute
measurements.
SPECIFICATIONS
he
Model
|
te
4008
|
mv
to
300
v
full
scale,
12
ranges
Frequency
range
10
cps
to
10
mc
Calibration reads rms value of sine wave; voltage indication pro-
portional to absolute average value of applied wave;
3 MV to 300 V RANGES
db scale —10 to + 2 db, 10 db between ranges: 100
Frequency 10CPS 20CPS 40CPS 500 KC 2MC
divisions on 0 to | scale.
1MC 4MC 10 MC
AT FULL SCALE
AT 1/3 FULL SCALE
reads rms value of sine wave; voltage indication propor-
tional
to
absolute
average
value
of
applied
wave:
linear|'
db
scale
—10
db
to
+2
db.
10
db
between
ranges:
logarithmic
voltage
scales
0.3
to
|
and
0.8
to
3:
120
divisions from — 10 to +2 db.
HP MODEL 400E
ACCURACY % Of Reading
ACCURACY % Of Reading
1 MY RANGE
Frequency
10CPS
20CPS
40CPS
100
CPS
100
KC
500
KC
2MC
6MC
200 KC 1MC 4MC
AT FULL SCALE
AT 1/3 FULL SCALE
— 10
AT 1/10 FULL SCALE

Page 4
Model 400E/EL
SPECIFICATIONS (Cont.)
HP MODEL 400EL
ACCURACY % Of Reading
3 MV to 300 V RANGES
Frequency 10CPS 20CPS 40CPS
AT FULL SCALE
==]
AT 1/3 FULL SCALE +4, [a2
500 KC 2Mc
IMC 4MC 10 MC
| MV RANGE
Frequency
AT 1/3 FULL SCALE ele
10CPS 20CPS 40CPS
ACCURACY % Of Reading
500 KC 2MC 6 MC
200 KC 1MC 4MC
HP MODELS 400E/EL
AC-to-DC CONVERTER OUTPUT
ACCURACY % Of Reading
10CPS 20CPS 40CPS 100 CPS
3 MV-300 V RANGES
Frequency
AT 1/3 FULL SCALE
| MV RANGE
Frequency
AT FULL SCALE +2 &
AT 1/3 FULL SCALE
10CPS 20CPS 40CPS 100 CPS
“For 15°C - 40°C on 1 mv - 1 volt ranges only
HP MODEL 400E/EL
Input Impedance: 10 megohms shunted by 24 pf on the
1 mv-lv ranges and 10 megohms shunted by 9 pf on
the 3v-300v ranges.
Amplifier AC Output: 150 mv rms for full scale meter
indication; output impedance 50 ohms, 10 cps to 10 mc
(105 mv on the 1 mv range).
AC.DC Converter Output: 1 vdce output for full scale
meter deflection.
Output Resistance: 1000 ohms.
Response Time: 1 second to within 1% of final value
for a step change.
AC Power: 115 or 230 volts +10%, 50 to 1000 cps,
approx. 5 watts.
Temperature Range: 0 to +55°C (except where noted on
accuracy charts).
External Battery Operation:
Terminals are provided on rear panel; positive and nega-
tive voltages between 35v and 55v are required; current
drain from each voltage is approx. 54 ma. (External
switching and on/off monitoring should be used for
battery operation).
a
500 KC 2MC
100 KC 500 KC 2MC 6 MC
200 KC Cc
Weight: Net 6 Ibs. (2,7 kg), Shipping 9 Ibs. (4 kg).
Dimensions: 6-1/2” high, 5-1/8” wide, 11” deep (165,1
x 130,2 x 279,4 mm).
Price:
400E $285.00
A00EL $295.00
Option: 01 (400E only) reads directly in wolts and
db with db scale uppermost. Add $10.00
Option: 02 (400E or 400EL) front panel relative
control. Add $10.00.
Option: 03 (400E or 400EL) Constant Input ca-
pacity (10 megohms shunted by 28 pf) add §25.00
Option: 04 (400E only) includes all three options;
01, 02, and 03. Add $45.00.
Note: When ordering 2 options or less pleae desig-
nate each option.
Prices f.0.b. factory
Data subject to change without notice
& Indicates change from prior specifications
12 \.UG 65

Model 400E/EL . Section I
Paragraphs 1-1 to 1-6
SECTION I
GENERAL INFORMATION
1-1. DESCRIPTION.
1-2. The -hp- Models 400E and 400EL are versatile ac voltmeters and db
meters. Both models can be used as ac to de converters or wideband ampli-
fiers. The Model 400E is primarily intended for voltage measurements,
whereas the Model 400EL is primarily a db meter. However, both meters
indicate both volts anddb. The 400E has a linear ac scale with a logarithmic
db scale underneath, and the 400EL has a linear db scale with a logarithmic
ac scale underneath. Since the difference in scales is the only difference
between the two instruments, this manual will use the term 400E/EL in ref-
erence to both instruments.
1-3. The enclosed data sheet contains a complete description of the 400E/EL
along with a list of specifications.
1-4, INSTRUMENT AND MANUAL IDENTIFICATION.
1-5. Hewlett-Packard instruments are identified by a two-section, eight-
digit
serial
number
(000-00000).
If
the
first
three
digits
of
the
serial
num-
ber
on
your
instrument
do
not
agree
with
those
on
the
title
page
of
this
manual, change sheets supplied with the manual will define differences be-
tween
your
instrument
and
Model
400E/EL
described
in
this
manual.
1-6.
If
the
first
three
digits
of
the
two-section,
eight-digit
serial
number
are prefixed with an E or G, your instrument was produced in Europe. An
E000-00000
serial
number
indicates
that
the
instrument
was
manufactured
in England; a G000-00000 serial number indicates that the instrument was
manufactured in Germany.
1-1