IET Labs 1433 Series Troubleshooting guide

♦PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT ♦
Email: inf[email protected]
TEL: [phone] • FAX: [phone]
www.ietlabs.com
IET LABS, INC.
1433 SERIES
High-Accuracy
Decade Resistor
User and Service Manual
Copyright © 2018 IET Labs, Inc.
Visit www.ietlabs.com for manual revision updates
1433 im/October 2018
Effective for serial numbers beginning with “E”

Email: inf[email protected]
TEL: [phone] • FAX: [phone]
www.ietlabs.com
IET LABS, INC.

iTable of Contents
1433 Series
WARRANTY
We warrant that this product is free from defects in material and workmanship and, when properly used,
will perform in accordance with applicable IET specifications. If within one year after original shipment,
it is found not to meet this standard, it will be repaired or, at the option of IET, replaced at no charge when
returned to IET. Changes in this product not approved by IET or application of voltages or currents greater
than those allowed by the specifications shall void this warranty. IET shall not be liable for any indirect,
special, or consequential damages, even if notice has been given to the possibility of such damages.
THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED,
INCLUDING BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY OR
FITNESS FOR ANY PARTICULAR PURPOSE.

ii Table of Contents
1433 Series
WARNING
OBSERVE ALL SAFETY RULES
WHEN WORKING WITH HIGH VOLTAGES OR LINE VOLTAGES.
Dangerous voltages may be present inside this instrument. Do not open the case
Refer servicing to qualified personnel
HIGH VOLTAGES MAY BE PRESENT AT THE TERMINALS OF THIS INSTRUMENT
WHENEVER HAZARDOUS VOLTAGES (> 45 V) ARE USED, TAKE ALL MEASURES TO
AVOID ACCIDENTAL CONTACT WITH ANY LIVE COMPONENTS.
USE MAXIMUM INSULATION AND MINIMIZE THE USE OF BARE
CONDUCTORS WHEN USING THIS INSTRUMENT.
Use extreme caution when working with bare conductors or bus bars.
WHEN WORKING WITH HIGH VOLTAGES, POST WARNING SIGNS AND
KEEP UNREQUIRED PERSONNEL SAFELY AWAY.
CAUTION
DO NOT APPLY ANY VOLTAGES OR CURRENTS TO THE TERMINALS OF THIS
INSTRUMENT IN EXCESS OF THE MAXIMUM LIMITS INDICATED ON
THE FRONT PANEL OR THE OPERATING GUIDE LABEL.

iiiTable of Contents
1433 Series
Contents
Chapter 1 Introduction ..............................................................................1
1.1 Product Overview ................................................................................................. 1
Chapter 2 Specifications ...........................................................................2
Decade Specifications .................................................................................................... 2
Chapter 3 Operation ..................................................................................5
3.1 Initial Inspection and Setup .................................................................................. 5
3.2 Connection ............................................................................................................ 5
3.2.1 General Considerations............................................................................... 5
3.2.2 Electrical Considerations ............................................................................ 5
3.2.3 Four-Wire Kelvin-Lead Connections ......................................................... 6
3.2.4 Thermal emf Considerations....................................................................... 6
3.3 Dial Setting ........................................................................................................... 6
Chapter 4 Maintanence..............................................................................7
4.1 Preventative Maintenance..................................................................................... 7
4.2 Calibration Interval ............................................................................................... 7
4.3 General Considerations......................................................................................... 7
4.4 Calibration Procedure ........................................................................................... 8
4.5 Schematic.............................................................................................................. 8
4.6 Replaceable Parts List........................................................................................... 9

iv Table of Contents
1433 Series
Tables and Figures
Figure 1-1: 1433 Series High Accuracy Decade Resistor.......................................1
Figure 2-1: Sample operating guide affixed to unit .................................................4
Figure 3-1: Optimal 4-Wire Kelvin Lead Connection...............................................6
Figure 4-1: 1433 Series Schematic Diagram ..........................................................8
Table 4-1: Replacement List....................................................................................9
Figure 4-2: 1433 Replaceable Parts .......................................................................9

1
1433 Series
Introduction
Chapter 1
INTRODUCTION
High-quality gold-plated, tellurium-copper binding
posts serve to minimize the thermal emf effects which
can introduce errors into dc resistance measurements.
All other conductors within the instrument, as well as
the solder employed, contain no metals or junctions
that contribute to thermal emf problems.
With a minimum resistance as low as 1 mΩand a
maximum available resistance of over 111 MΩ, the
1433 series may be used for exacting precision mea-
surement applications requiring high accuracy, good
stability, and low zero-resistance. They can be used
as components of dc and ac bridges, for calibration,
as transfer standards, and as RTD simulators.
The 1433 Series may be rack-mounted to serve as
components in measurement and control systems.
This series is part of a family of resistance substitut-
ers suitable for filling many engineering and testing
needs. Consult IET for:
HPRS High-power substituters - up to >400 W
HRRS High-resistance substituters - to 1 TΩ
RTD simulators
HARS-LX Laboratory-standard-grade substitut-
ers - to 1 ppm accuracy
PRS Programmable substituters - IEEE-488 or
BCD; SCPI protocol.
Figure 1-1: 1433 Series High Accuracy
Decade Resistor
1.1 Product Overview
The 1433 Decade Resistors are a family of instru-
ments providing a very broad choice of high-perfor-
mance resistance sources. Any number of decades
from one to eleven is available.
The 1433 is a precision resistance source with ex-
cellent characteristics of stability, temperature coef-
ficient, power coefficient, and frequency response.
There are over 30 models available covering a wide
resistance range from 1 mΩto over 111 MΩ. The
1433 Series employs stable, very-low-resistance
switches with silver-alloy contacts. A special design
keeps zero-resistance to less than 1 mΩper decade.
Self-cleaning keeps the silver contacts from becoming
tarnished when unused, or when only low currents
are passed through them. This is most often the case
when only minute test currents are drawn by digital
multimeters or other test instruments. Contact resis-
tance is stable and remains low and repeatable.
The dials, marked “0” to “10”, offer smooth rotation
from position to position with no stops. Each dial has
an overlap “10” position for maximum convenience
and flexibility in setting and adjusting resistance
values. The resistance per step and maximum cur-
rent of each dial are clearly shown on the front panel.
Electrical shielding is provided by an attractive alumi-
num cabinet and front panel. The resistance elements
have no electrical connection to the cabinet and panel;
a separate shield terminal is provided.

2
1433 Series
Specifications
Decade Specifications
Resistance
per step
Total
decade
resistance
Max current Max voltage
(per step)
Max power
(per step)
Stability
(±ppm/yr)
Long-term
stability
(±ppm/3 yrs)
Temperature
coefficient
(±ppm/°C)
Resistor type
1 mΩ10 mΩ8.0 A 5 mV 0.04 W 50 75 50
Resistance wire
10 mΩ100 mΩ4.0 A 40 mV 0.16 W 50 75 20
100 mΩ1 Ω1.6 A 0.16 V 0.25 W 50 75 20
1 Ω10 Ω0.8 A 0.8 V 0.6 W 20 25 20
Wirewound, non-
inductive
10 Ω100 Ω0.25 A 2.5 V 0.6 W 20 25 15
100 Ω1 kΩ80 mA 8 V 0.6 W 20 25 5
1 kΩ10 kΩ23 mA 23 V 0.5 W 20 25 5
10 kΩ100 kΩ7 mA 70 V 0.5 W 20 25 5
100 kΩ1 MΩ2.3 mA* 230 V* 0.5 W* 20 25 5
1 MΩ10 MΩ0.7 mA* 700 V* 0.5 W* 20 25 5
10 MΩ100 MΩ0.1 mA* 1000 V* 0.1 W* 50 100 10 Metal oxide film
*Subject to maximum of 2000 V to case
Chapter 2
SPECIFICATIONS
For the convenience of the user, the pertinent specifications are given in an OPERATING GUIDE affixed to
the case of the instrument.
Accuracy:
≤1 MΩdecades: ±(0.01% + 2 m)
10 MΩdecades: ±0.03%
after subtraction of zero resistance, at 23°C;
traceable to SI
Zero resistance:
≤1 MΩdecades: <1 mper decade at dc
10 MΩdecade: 3 mat dc
Max voltage to case:
2000 V peak
Terminals:
3 Gold-plated, 5-way, tellurium-copper binding
posts with low thermal emf and low resistance. Rear
outputs are available as an option.
-K Option: Kelvin connection to is available as an
option with 5 binding posts
Typical Value of Zero Impedance:
<0.001 /decade at 1 Hz.
0.04 /decade at 1 MHz
Proportional to square root of frequency above 100 kHz
Switch capacitance:
< 1 pF between contacts
Zero Inductance (Lo):
0. 1 H/decade + 0.2 H.
Switches:
Continuous rotation
11 positions marked “0”-”10”
Multiple solid silver-alloy contacts
Environmental conditions:
Operating: 10°C to 40°C
Storage: -40°C to 70°C
Humidity: <80% RH
Supplied with unit:
Instruction manual
Calibration Certificate

3
1433 Series
Specifications
Mechanical:
Model Dimensions Weight
3 decade
31 cm W x 8.9 cm H x 10.2 cm D
(12.2" x 3.5" x 4") 1.7 kg 3.8 lb
4-5 decade
37.6 cm W x 8.9 cm H x 10.2 cm D
(14.8" x 3.5" x 4") 2.0 kg 4.3 lb
6-7 decades
43.9 cm W x 8.9 cm H x 10.2 cm D
(17.3" x 3.5" x 4") 2.4 kg 5.3 lb
8-9 decades
48.3 cm W x 17.8 cm H x 17.8
cm D
(19" x 7" x 7")
3.5 kg 7.7 lb
10-11 decades
3.7 kg 8.1 lb
Ordering Information:
Model Total resistance Number of
decades Resolution
Historic
GR model
numbers
1433-01 1.11 Ω3 0.001 Ω
1433-00 111.1 Ω4 0.01 Ω1433-U
1433-02 1.111 kΩ4 0.1 Ω1433-K
1433-04 11.11 k Ω4 1 Ω1433-J
1433-06 111.1 k Ω4 10 Ω1433-L
1433-08 1.111 MΩ4 100 Ω1433-Q
1433-09 11.11 MΩ4 1 kΩ
1433-09A 111.1 MΩ4 10 kΩ
1433-10 1.1111 kΩ5 0.01 Ω1433-T
1433-12 11.111 kΩ5 0.1 Ω1433-N
1433-14 111.11 kΩ5 1 Ω1433-M
1433-16 1.1111 M Ω5 10 Ω1433-P
1433-18 11.111 MΩ5 100 Ω1433-Y
1433-18A 111.11 MΩ5 1 kΩ
1433-19 1.111 11 kΩ6 0.001 Ω
1433-20 11.1111 kΩ6 0.01 Ω1433-W
1433-22 111.111 kΩ6 0.1 Ω1433-X
1433-24 1.111 11 MΩ6 1 Ω1433-B
1433-26 11.1111 MΩ6 10 Ω1433-Z
1433-27 111.111 MΩ6 100 Ω
1433-28 11.111 11 kΩ7 0.001 Ω
1433-29 111.1111 k Ω7 0.01 Ω1433-F
1433-31 1.111 111 MΩ7 0.1 Ω1433-G
1433-33 11.111 11 MΩ7 1 Ω1433-H
Model Total resistance Number of
decades Resolution
Historic
GR model
numbers
1433-34 111.1111 MΩ7 10 Ω
1433-35 111.111 11 kΩ8 0.001 Ω
1433-36 1.111 111 1 MΩ8 0.01 Ω
1433-37 11.111 111 MΩ8 0.1 Ω
1433-38 111.111 11 MΩ8 1 Ω
1433-39 1.111 111 11 MΩ9 0.001 Ω
1433-39A 11.111 111 1 MΩ9 0.01 Ω
1433-39B 111.111 111 MΩ9 0.1 Ω
1433-40A 11.111 111 11 MΩ10 0.001 Ω
1433-40 111.111 111 1 MΩ10 0.01 Ω
1433-41
111.111 111 11 MΩ 11 0.001 Ω
OPTIONS:
1433-50: Rack Mount Kit (4-dial)
1433-51: Rack Mount Kit (5-dial)
1433-52: Rack Mount Kit (6 and 7-dial)
1433-XX-RO: Rear output binding posts
1433-XX-K: Kelvin-type 4-terminal posts

4
1433 Series
Specifications
1 mȍ10 mȍ8.0 A 5 mV 0.04 W ±50 ppm/yr ±75 ppm/3 yrs ± 50 ppm/°C
10 mȍ100 mȍ4.0 A 40 mV 0.16 W ±50 ppm/yr ±75 ppm/3 yrs ± 20 ppm/°C
100 mȍ1 ȍ1.6 A 0.16 V 0.25 W ±50 ppm/yr ±75 ppm/3 yrs ± 20 ppm/°C 1 ȍ10 ȍ0.8 A 0.8 V 0.6 W ±20 ppm/yr ±25 ppm/3 yrs ± 20 ppm/°C 10 ȍ100 ȍ0.25 A 2.5 V 0.6 W ±20 ppm/yr ±25 ppm/3 yrs ± 15 ppm/°C
100 ȍ1 kȍ80 mA 8 V 0.6 W ±20 ppm/yr ±25 ppm/3 yrs ± 5 ppm/°C
1 kȍ10 kȍ23 mA 23 V 0.5 W ±20 ppm/yr ±25 ppm/3 yrs ± 5 ppm/°C 10 kȍ100 kȍ7 mA 70 V 0.5 W ±20 ppm/yr ±25 ppm/3 yrs ± 5 ppm/°C 100 kȍ1 Mȍ2.3 mA* 230 V* 0.5 W* ±20 ppm/yr ±25 ppm/3 yrs ± 5 ppm/°C
1 Mȍ10 Mȍ0.7 mA* 700 V* 0.5 W* ±20 ppm/yr ±25 ppm/3 yrs ± 5 ppm/°C 10 Mȍ100 Mȍ0.1 mA* 1000 V* 0.1 W* ±50 ppm/yr ±100 ppm/3 yrs ± 10 ppm/°C Metal oxide film
*Subject to maximum of 2000 V to case
Wirewound,
non-inductive
Stability Long-term
stability
Temp.
coeffieient
Resistor
type
Total
deacde
resistance
Max
current
Resistance
per step
Power
per/step
Max
voltage
Resistance
Wire
1433 SERIES PRECISION DECADE RESISTORS
Accuracy: ≤≤
≤≤
≤1 MΩΩ
ΩΩ
Ω steps: ±(0.01% + 2 mΩ)
10 MΩΩ
ΩΩ
Ω steps: ±0.03%
At 23°C, after subtraction of zero resistance Traceable to SI
Zero Resistance: ≤≤
≤≤
≤1 MΩΩ
ΩΩ
Ωsteps: ≤1 mΩper decade
10 MΩΩ
ΩΩ
Ω steps: approx. 3 mΩ
Max Voltage to Case: 2000 V peak Switch Type: Multiple solid silver alloy contacts; continuous-
rotation; 11 positions marked "0" to "10".
Operation: If switches have not been operated for an extended period, they should be rotated a few times in both directions to restore contact resistance to specifications. Operating Conditions: +10 to + 40°C, <50% RH.
WARNING
1433 lbl/1433 genl/p4/48%/02-07-2013
IET LABS, INC. • 534 Main Street, Westbury, NY 11590 • [phone] • Fax: [phone]
CAGE CODE: 62015
formerly made by
*HQ5DG www.ietlabs.com
Observe all safety rules when working with high voltages or line voltages. Connect the (G) terminal to earth ground in order to maintain the case at a safe voltage. Whenever hazardous voltages (>45 V) are used, take all measures to avoid accidental contact with any live components: a) Use maximum insulation and minimize the use of bare conductors. b) Remove power when adjusting switches. c) Post warning signs and keep personnel safely away.
MODEL:1433-26 SN:E1-13013757
Figure 2-1: Sample operating guide affixed to unit

5
1433 Series
Operation
3.1 Initial Inspection and Setup
This instrument was carefully inspected before ship-
ment. It should be in proper electrical and mechanical
order upon receipt.
An OPERATING GUIDE is attached to the case
of the instrument to provide ready reference to
specifications.
3.2 Connection
3.2.1 General Considerations
The 1433 Series Decade unit provides three terminals
labeled H(high), L(low), and G (ground). The H and
L terminals are connected to the set resistance; the G
terminal is connected to the case. The G terminal may
be used as a guard or shield terminal. It may also be
connected (using a shorting link) to the Lterminal
to allow two-terminal as opposed to three-terminal
measurements.
In order to make the most stable measurements, de-
termine which is the more sensitive of the two user
leads, i.e. the one going into a higher impedance. This
lead should be connected to the more protected of
the two terminals: H(high) or L(low). That would
either be the terminal that is shorted to the case, or
the Lterminal if neither is connected to the G(case).
If switches have not been operated for an extended
period, they should be rotated a few times to assure
that contact resistance is within specifications.
3.2.2 Electrical Considerations
In order to make proper use of the full performance
capabilities of the 1433 unit, especially if low resis-
tance or low-resistance increments are important, take
care when connecting to the terminals. In particular,
in order to keep contact resistance to a minimum,
make the most substantial and secure connection to
the binding posts. They accept banana plugs, tele-
phone tips, spade lugs, alligator clips, and bare wire.
The largest or heaviest mating connection should be
made, and, where applicable, the binding posts should
be securely tightened.
These considerations may be relaxed whenever single
milliohms are considered insignificant for the task
being performed.
Chapter 3
OPERATION

6
1433 Series
Operation
Figure 3-2: 4-Wire connection to a 5-terminal
unit
HIGH
CURRENT
LOW
CURRENT
GND
I+ I-
V+ V-
Ground
HIGH
SENSE
LOW
SENSE
3.2.3 Four-Wire Kelvin-Lead
Connections
Whenever possible, 4-wire Kelvin leads (the best
connection) should be employed. Such a connection
minimizes the effects of contact resistance and ap-
proaches ideal performance.
If the four terminals are available as clamps similar
to alligator clips, they may be connected to the necks
of the binding posts on a 3-terminal unit. If the four-
wire connections are available separately, the optimal
connections are shown in Figure 3-1 and Figure3-2.
HIGH LOW GND
I+ I-
V+ V-
Ground
Figure 3-1: 4-Wire connection to a 3-terminal
unit

7
1433 Series
Operation
3.2.4 Thermal emf Considerations
The highest-quality low-emf components are used
in the 1433 Series. There nevertheless may be some
minute thermal emf generated at the test leads where
they contact the gold-plated binding posts.
This emf will not manifest itself if an ac measurement
instrument is employed. It will also be eliminated
if a meter with a “True Ohm” capability is used.
Otherwise it may appear as a false component of the
dc resistance measurement. It is possible to eliminate
this component of the reading error by taking a second
measurement with the leads reversed and averaging
the readings.
3.3 Dial Setting
Whenever the dials are used in positions 0-9, the
resulting resistance is read directly. The decimal
point and the steps are clearly marked on the panel.
For additional flexibility and range, each decade
provides a “10” position setting. This “10” position
on any one decade equals the “1” position on the next
higher decade. It adds about 11% to the nominal total
decade resistance.
To determine the resistance obtained when one or
more “10” settings are used, simply add “1” to the
next higher decade. For example, a setting of 3-6-
10-0-10 becomes:
3 3 0 0 0 0
6 6 0 0 0
10 1 0 0 0
0 0 0
10 1 0
____________________________
TOT 3 7 0 1 0
and a setting of 10-10-10-l0-10.10 Ωbecomes:
10 1 0 0 0 0 0.0
10 1 0 0 0 0.0
10 1 0 0 0.0
10 1 0 0.0
10 1 0.0
.10 1.0
____________________________
TOT 1 1 1 1 1 1.0

8
1433 Series
Maintanence
Chapter 4
MAINTANENCE
4.1 Preventative Maintenance
Keep the unit in a clean environment. This will help
prevent possible contamination.
The 1433 is packaged in a closed case, which limits
the entry of contaminants and dust to the inside of
the instrument. If it is maintained in a clean or air-
conditioned environment, cleaning will seldom be
required. In a contaminated atmosphere, cleaning
may be required.
Should cleaning be needed, do the following:
1. Remove the 4 screws from the sides of the
housing, and remove the housing.
2. Remove any dust or debris using optical
grade dry compressed air or a clean brush.
3. Should switch contact cleaning or lubrica-
tion be required, as may be indicated by an
increase in the zero resistance, this may be
done be spraying the switch contacts with
a conditioning compound such as WD-40
or Deoxit from Caig Laboratories, or Super
Lube with PTFE from Synco Chemical Corp.
4. Replace the housing and reinstall the 4 hous-
ing screws.
The front panel should be periodically cleaned to
eliminate any leakage paths around the binding posts.
To do this wipe the front panel clean using alcohol
and a lint-free cloth.
4.2 Calibration Interval
The recommended calibration interval for 1433
Series decade substituters is twelve (12) months. The
calibration procedure may be carried out by the user
if a calibration capability is available, by IET Labs,
or by a certified calibration laboratory. If the user
should choose to perform this procedure, then the
considerations below should be observed.
4.3 General Considerations
It is important, whenever testing the 1433 Series
Decade Units, to be very aware of the capabili-
ties and limitations of the test instruments used. A
resistance bridge may be employed, and there are
direct-reading resistance meters or digital multimeters
available that can verify the accuracy of these units,
especially when used in conjunction with standards
that can serve to confirm or improve the accuracy of
the testing instrument
Such test instruments must be significantly more accu-
rate than ±(l00 ppm+2 mΩ) for all applicable ranges,
allowing for a band of uncertainty of the instrument
itself. A number of commercial bridges and meters
exist that can perform this task; consult IET Labs.
It is important to allow both the testing instrument
and the 1433 to stabilize for a number of hours at
the nominal operating temperature of 23°C, and at
nominal laboratory conditions of humidity <80% RH.
There should be no temperature gradients across the
unit under test.

9
1433 Series
Maintanence
Substantial Kelvin-type 4-wire test terminals should
be used to obtain accurate low-resistance readings.
It is convenient, once the zero resistance has been
determined, to subtract it from the remaining mea-
surements. This can be automatically done in many in-
struments which have an offset subtraction capability.
4.4 Calibration Procedure
1. Employ proper metrological practices.
Allow a confidence band for the uncer-
tainty of the measuring instrument and
setup.
2. Confirm the zero resistance of the unit.
3. Determine the allowable upper and lower
limits for each resistance setting of each de-
cade based on the specified accuracy.
For the 1433 series, these limits for any
resistance “R” are [R±(0.0001 R + 2
mΩ)].
4. Confirm that the resistances fall within these
limits after subtraction of the zero resistance.
5. If any resistances fall outside these limits,
the associated switch assembly may require
trimming or replacement.
4.5 Schematic
Figure 4-1 gives the schematic of the 1433 decade
unit.
Figure 4-1: 1433 Series Schematic Diagram

10
1433 Series
Maintanence
4.6 Replaceable Parts List
Model Ref IET Pt No Description
1 BP-1000-RD Binding Post, Red
2 BP-1000-BK Binding Post, Black
3 BP-1000-GN Binding Post, Green
4 1433-4300-KNB Knob Assembly
Not Shown 1433-3100 Foot
Not Shown 1433-4000-X-.001 1 m/step Decade Switch Assembly
Not Shown 1433-4000-X-0.01 10 m/step Decade Switch Assembly
Not Shown 1433-4000-X-0.1 100 m/step Decade Switch Assembly
Not Shown 1433-4000-X-1 1 /step Decade Switch Assembly
Not Shown 1433-4000-X-10 10 /step Decade Switch Assembly
Not Shown 1433-4000-X-100 100 /step Decade Switch Assembly
Not Shown 1433-4000-X-1k 1 k/step Decade Switch Assembly
Not Shown 1433-4000-X-10k 10 k/step Decade Switch Assembly
Not Shown 1433-4000-X-100k 100 k/step Decade Switch Assembly
Not Shown 1433-4000-X-1M 1 M/step Decade Switch Assembly
Not Shown 1433-4000-X-10M 10 M/step Decade Switch Assembly
Table 4-1: Replacement List
Figure 4-2: 1433 Replaceable Parts
1
2
3
4