IET Labs 1565-E Troubleshooting guide

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REPRODUCTION AND DISTRIBUTION OF THIS TECHNICAL MANUAL
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We warrant that this product is free from defects in material and workmanship and, when properly used,
will perform in accordance with applicable IET specifi cations. 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 specifi cations 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.

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 qualifi ed 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.
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.

2.1 Model Confi guration and Specifi cations ........................................................................3
2.2 General Specifi cations ...................................................................................................4
3.1 Initial inspection and setup ............................................................................................7
3.2 Connection .....................................................................................................................7
3.2.1 General Considerations ........................................................................................7
3.2.2 Electrical Considerations ......................................................................................7
3.2.3 Four-Wire Kelvin Lead Connections ...................................................................7
3.2.4 Thermal emf Considerations ................................................................................7
3.3 Dial Setting ....................................................................................................................8
3.4 Environmental Conditions .............................................................................................8
3.5 Local Operation .............................................................................................................8
3.6 Remote Operation ..........................................................................................................8
8.1 Verifi cation of Performance
8.2 Calibration Interval

1.1 Introduction
The 1565-E is a Type 2, general purpose SLM
with corresponding to ANSI S1.4-1983 Type 2
and IEC61672-1:2013 Class 2
The chief use of the SLM is making noise
measurements in a work place such as: routine
measurements of offi ce building HVAC sys-
tems, machinery, traffi c noise, and other noises
of a reasonably constant character.
1.2 Description
The instrument is housed in a high impact
molded plastic case that is shaped for comfort-
able hand-held operation and tapered at the
microphone end to minimize the effect of case
diffraction.
It consists of the following elements: a mi-
crophone to pickup sound; an amplifi er, to
raise the microphone output to useful levels; a
calibrated attenuator, to adjust the amplifi ca-
tion to a value appropriate to the sound level
being measured; a display, networks, to adjust
the frequency characteristic of the response (A
or C weighting) ; and an output connection, to
accommodate additional measuring equipment.
It covers the sound-level range from 35 to 130
dB in 2 overlapping ranges.
Figure 1 1565-E Sound Level Meter

For convenience to the user, the pertinent
specifi cations are given in an OPERATING
GUIDE, shown typically in Figure 2.1, affi xed
to the case of the instrument.
2.1 Specifi cations
Sound level range: 35 to 130 dB re 20 µN/m2
Sound level accuracy: ±1.5 dB
Frequency range: 31.5 Hz to 8 kHz
Weighting: A and C
Output: 3.5 mm mini-jack
ac Output: >0.65 Vrms behind 600 Ω at full
scale; will drive oscilloscope or low-imped-
ance headphones
dc Output: 10 mV/dB
Display: 3-1/2 digit LCD display, full scale
sound-level range set by Range select switch,
greater than 10 dB portion of scale for sound-
level comparisons on 2 ranges, and low end of
sound-level range set by range select switch.
Power: One 9V (6F22 or equivenent) alkaline
battery supplied, provides 50+ hours of opera-
tion
Environmental:
Temperature: 0 to 50°C operating
-40 to +60°C storage, with batteries removed
Humidity: <95% RH non-condensing
Weight: 0.21 kg (7 oz) net, 1.4 kg (3 lb) ship-
ping
Dimensions: 24 cm H x 6.8 cm W x 2.5 cm D
(9.45” x 2” x 1”)
Accessories supplied: Instruction manual,
windscreen, adjustment screwdriver and carry-
ing case
Additional Specifi cations
Standard: Conforms to ANSI S1.4-1983 Type
2 and IEC61672-1:2013 Class 2
Dynamic range: 55 dB with 2 ranges Lo and
Hi
Ranges: Lo: 35 - 90 dB and Hi: 75 - 130 dB
Time weighting: rms response with fast 125
mS and slow 1 s
Microphone: 1/2” electret condenser micro-
phone
Resolution: 0.1 dB
Calibration: Internal oscillator at 1 kHz and
94 dB
Recommended calibration interval: 12
months

FIGURE 2.1 Typical OPERATING GUIDE Affi xed to Unit
(Please see label affi xed to your unit)

3.1 Initial inspection and setup
This instrument was tested and carefully in-
spected before shipment. 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 refer-
ence to specifi cations.
Precautions:
• Care should be taken to keep the SLM and
microhone clean and dry
• Do not store in areas of high humidity for
extended periods
• Avoid subjecting the SLM to excessive
vibration
• Remove batteries when stored for long
periods of time
3.1.2
Accessories Included
1. 1565-E Sound Level Meter Instruction
Manual
2.) Carry case for SLM and accessories
1565-E-CASE
3.) Windscreen 1565-E-WS
4.) Adjustment screwdriver 1565-0440-01
5.) 9 V battery 6F22
6.) Phone plug for ac/dc output 1565-E-PP
3.1.3 Key Features
1. 1/2” Electret Microphone
2. LCD display
3. POWER OFF & RANGE select switch
4. RESPONSE & HOLD select switch
5. A/C weighting and Calibration switch
6. Calibration adjust screw for 94dB
7. Reset key (resets max hold reading)
8. AC/DC analog output 3.5mm phone jack
9. Battery compartment on rear of meter
Note: The threaded tripod mount screw hole is
on the center rear of the meter (not shown).
Figure 3-1 Key Features
3.1.4
Condensed Operating Instructions
1. Power the meter by moving the RANGE
switch to the LO or HI range position, the me-

ter will begin measuring sound levels.
If the LCD does not display, check the battery.
2. Set the RESPONSE switch to Slow and
FUNCTION switch to A for typical measure-
ments.
2. Place the meter on a tripod via the tripod
mount on the rear of the meter or hold the me-
ter in hand to take noise measurements.
3. Point the microphone toward the source of
the sound level to be measured and view the
reading on the meter’s LCD. An indication of
‘OVER’ means that the measurement is out
of range, try selecting the other measurement
range.
4. Use the supplied windscreen to reduce wind
noise when appropriate.
3.2 Key Feature Descriptions
3.2.1 ‘A’ and ‘C’ Weighting
Select ‘A’ or ‘C’ Weighting via the FUNCT
switch. Use ‘A’ weighting to have the meter
respond as the human ear would with regard
to frequency response (the human ear boosts
and cuts amplitude over the frequency spec-
trum therefore it is not ‘fl at’ responding). ‘A’
weighting is used for environmental measure-
ments, OSHA regulatory testing, law enforce-
ment, and workplace design.
Select ‘C’ weighting for fl at response measure-
ments (no amplitude boost or cut across the
frequency spectrum). ‘C’ weighting is suitable
for the sound level analysis of machines, en-
gines, etc. which have higher sound levels.
3.2.2 FAST/SLOW Response Time
Select either FAST (125msec response) or
SLOW (1sec response) measurement mode via
the RESPONSE switch. Selection of Fast or
Slow is determined by the application and any
directives or standards related to that applica-
tion. For example, most hearing conservation
or OSHA related testing is done using SLOW
mode and A weighting.
3.2.3 MAX HOLD
In this mode, the meter takes continuous mea-
surements and only updates the LCD when a
higher reading than the one presently on the
display is detected. Select MAX HOLD using
the RESPONSE switch. The LCD will refl ect
the MAX HOLD function. Press the RESET
key to reset the MAX HOLD reading.
3.2.4 Analog Outputs
The meter includes an AC and a DC analog
output for use with chart recorders, datalog-
gers, etc. The AC output is 0.65V rms full
scale and the DC output is 10mV per dB. The
3.5mm output mini-jack is located on the right
side of the instrument. Confi gure a mini-plug
for use with AC, DC, or both as shown in the
diagram below: This is a diagram of a 3.5mm
phone plug used to connect to the meter. Select
the output wires (referenced to ground) cor-
responding to the AC, DC, or both signals to
connect to chart recorders, dataloggers, etc.
Figure 3-2 Phono Plug
3.3 Calibration Check
The 1565-E can be calibrated using an external
calibrator, which is recommended or the inter-
nal calibrator.
3.3.1 Internal Calibration
This meter provides a built-in calibration

adjustment. The calibration adjustment potenti-
ometer is located on the front panel beneath the
FUNCT switch. Put the switches to the F, Hi,
A, a CAL 94dB positions and adjust the poten-
tiometer for a display of exactly 94.0dB.
3.3.2 External Calibration
Attach an external sound level calibrator such
as the IET Labs 1562-A Sound Level Calibra-
tor (1kHz at 114 dB) or similar calibrator at
94 dB or 114 dB, completely over the micro-
phone. Set the meter to F, Hi, and A, and ad-
just the potentiometer for a display of exactly
94.0dB or 114 dB for 1562-A.
If the internal and external settings are not
within 1.5dB of each other, the meter will
require repair.

4.1.1 Calibration Interval
The 1565-E Sound Level Meter should be veri-
fi ed for performance at a calibration interval
of twelve (12) months. This procedure may be
carried out by the user, if a calibration capa-
bility is available, by IET Labs, or by a certi-
fi ed calibration laboratory. If the user should
choose to perform this procedure, then the
considerations below should be observed.
4.1.2 General Considerations
The equipment, methods. and criteria for veri-
fying the specifi ed performance of the SLM are
presented in the following paragraphs.
4.1.3 Equipment Required
• IET/GenRad 1986 Omnical or equiva-
lent sound level calibrator
• 1/2” Microphone Adapter
Proper metrology practices should be followed
in performing this verifi cation.
4.2 Calibration Procedure
Calibration consists of tests for range tracking
and frequency characteristics.
4.2.1 Meter Tracking
Meter Tracking tests the accuracy of the meter
in different SPL ranges. The test specifi cations
come from ANSI S1.4-1971, Type 2 tolerances.
Use a 1565-E worksheet
Insert the microphone of the DUT fully into the
transducer of the 1986.
Set the DUT measurement speed to fast. This
speed will be used for all tests.
Turn on the DUT, and select C weighting. Se-
lect the Hi range. Set the 1986 to 1 kHz @ 94
dB and Calibrated SPL. Adjust the CAL 94dB
potentiometer on the DUT, if needed, to bring
displayed value to 94 dB.
Record the meter reading for each value and
range listed in the worksheet and compare with
specifi cation listed on the worksheet.
4.2.2 Frequency Characteristics of the C,
and A Weighting Networks
This tests the accuracy of the meter at various
frequencies and weightings.
Set the 1986 calibrator to 114 dB. All of these
tests are conducted at 114 dB.
Set the range of the DUT to Hi 75 - 130 dB.
The range of the DUT may have to be changed
depending on the test frequency and weighting.
Set the DUT weighting to C. Record and repeat
testing, for each frequency on the calibrator as
needed to complete the worksheet.
Set the DUT weighting to A Record the DUT
reading on the worksheet. Record and repeat
testing, for each frequency on the calibrator as
needed to complete the worksheet.
Be sure to check that the readings are within
specifi cation.

1565-E Calibration Worksheet
Function Nominal Settings DUT Range Specifi cations
±1.5 dB Reading Pass/Fail
Meter Tracking
84 dB LO 82.5 - 85.5 dB
84 dB Hi 82.5 - 85.5 dB
94 dB HI 92.5 - 95.5 dB
114 dB HI 112.5 - 115.5 dB
Frequency
Characteristics
C Weighting
125 Hz 113.8 dB
HI
112.3 - 115.3 dB
250 Hz 114.0 dB 112.5 - 115.5 dB
500 Hz 114.0 dB 112.5 - 115.5 dB
1 kHz 114.0 dB 112.5 - 115.5 dB
2 kHz 113.8 dB 112.3 - 115.3 dB
4 kHz 113.2 dB 111.7 - 114.7 dB
A Weighting
125 Hz 97.9 dB
HI
96.4 - 99.4 dB
250 Hz 105.4 dB 103.9 - 106.9 dB
500 Hz 110.8 dB 109.3 - 112.3 dB
1 kHz 114.0 dB 112.5 - 115.5 dB
2 kHz 115.2 dB 113.7 - 116.7 dB
4 kHz 115.0 dB 113.5 - 116.5 dB

4.3.1 Service and Maintenance
The 1565-E Sound Level Meter requires no
service or maintenance other than annual cali-
bration.
The 1565-B operates on a standard 9 V transis-
tor battery. The battery is located at the bottom
rear of the 1565-E.
The battery slides toward the bottom to expose
the 9 V transistor battery.
This battery should be removed when not in
use to prevent damage to the 1565-E.
If there is no display when 1565-E is turned on
replace the 9 V battery.
There are no parts that require routine mainte-
nance inside the 1565-E..
4.3.2 Display Window
The display window 1565-E-200 can be
scratched. Care should be taken to clean with
soft cloth.
4.3.3 Disassembly of the 1565-E
The 1565-E can be disassembled by removing
the two screws located on the rear of the 1565-
E .
Remove these two screws and the the rear
cover of the 1565-E can be carefully pried or
seperated from the front cover and electronics.
A list of replacement parts is shown in section
4.2.
4.2 Replacement Parts
The replacement parts corresponding to Figure
4.3.
Item # Description Part Number
1 1/2” Microphone and
Preamp Assembly
1565-E-100
2 Display Window 1565-E-200
3 - 9 Case Assembly with
buttons and battery
cover
1565-E-300
10 PCB Assembly with
LCD Display (not
shown)
1565-E-400
11 9 V Battery snap with
contracts (not shown)
1565-E-500
Figure 4.3 Replacement Parts

4.3 Troubleshooting
1.) Setting RANGE switch to Hi or Lo does
not turn on the SLM. - Replace battery
2.) Meter Tracking is not within ±1.5 dB -
1565-E requires factory service
3.) 1565-E does not display 94 dB when set
to internal calibration function of when using
external calibrator. - Adjust calibration poten-
tiometer on front panel This is a normal part of
operation of the 1565-E
4.4 Block Diagram
A block diagram showing the basic multimeter
design is shown below.
Block Diagram