Riken Keiki GX-8000 User manual

PT-xxx
Portable Gas Monitor
GX-8000
Operating Manual
Request for the Customers
•Read and understand this operating manual before using the gas monitor.
•Use the gas monitor in accordance with the operating manual.
•Regardless of warranty period, we shall not make any compensation for accidents and
damage caused by using this product.
•Because this is a safety unit, daily maintenance, gas calibration for every six months, and
regular maintenance must be performed.
•The sensors of the gas monitor, having its sensor life, must be replaced at regular intervals.
•If any abnormality was found in the gas monitor, notify them to Riken Keiki headquarters or
authorized local representative immediately.

Safety information
The Portable Gas Monitor Model GX-8000 is a gas monitor designed to provide continuous exposure
monitoring of combustible gas, oxygen (O2), toxic gas such as carbon monoxide (CO) and hydrogen sulfide
(H2S) in hazardous environments. The gas sample is sucked in by build-in micro pump.
The battery can be selected either Li-ion battery or alkaline dry battery.
Li-ion battery unit is called BUL-8000 and alkaline dry battery unit is called BUD-8000.
The battery unit can be changed even by the end users.
Specification for safety
・Ga Ex ia IIC T4
・Ambient temperature range for use ：-20°C to +50°C
・Ambient temperature range during battery charging ：0°C to +40°C
Electrical data
・Power supply of Li-ion battery unit : BUL-8000
Two parallel connected Li-ion cells used in battery pack BP-8000 are from type Maxell
INR18650PB1. Um=250V.
・Power supply of alkaline battery unit : BUD-8000
Powered by three series AA size alkaline batteries , model LR6 by TOSHIBA.
・Backup battery type CR1220 manufactured by Maxell.
Certificate numbers
・IECEx Certificate number ：IECEx KEM 10.0038
・ATEX Certificate number ：KEMA 10ATEX 0085
List of standards
・IEC 60079-0：2004 ed.4.0 ・EN60079-0:2006
・IEC 60079-11：2006 ed.5.0 ・EN60079-11:2007
・IEC 60079-26：2006 ed.2 ・EN60079-26:2007
WARNING
・Do not charge in hazardous location.
・Do not charge it expect by genuine charger.
・Do not replace battery unit in hazardous location.
・Do not replace dry batteries in hazardous location.
・Do not attempt to disassemble or alter the instrument.
・Use only battery unit type BUD-8000 with three series connected Alkaline
AA batteries, type LR6 manufactured by Toshiba, or use chargeable battery unit
type BUL-8000.
INST. No. 0 0 0 0 0 0 0 0 0 0 0
 AB C D E
A: Manufacturing year (0-9)
B: Manufacturing month (1-9,XYZ for Oct.-Dec.)
C: Manufacturing lot
D:Serialnumber
E: Code of factory
・II 1 G Ex ia IIC T4
2-7-6Azusawa,Itabashi-ku,Tokyo,174-8744,Japan
Phone :[phone]
Fax :[phone]GIII
E-mail :[email protected]
Website :http://www.rikenkeiki.co.jp

- 3 - GX-8000
Preface
Thank you for choosing our portable gas monitor GX-8000.
This gas monitor is a multi gas detector that enables simultaneous monitoring of combustible gases, oxygen,
and toxic gases (hydrogen sulfide and carbon monoxide) in the air and high-concentration combustible
gases in N2 and inert gases.
Note that detection results are not intended to guarantee life or safety in any way.
The gas monitor can measure two types of combustible gases, "general combustible gases (HC)" to be
used in ordinary factories, oil tankers, etc. and "methane (CH4)" such as city gas and natural gas.
The gas monitor comes in several types for different combinations of gases to be measured. Check the
specifications of the gas monitor before use and conduct measurement properly in accordance with
purposes. (See the list of gases to be measured at the end of this operating manual.)
This manual explains how to use the gas monitor. Not only the first-time users but also the user who have
already used a gas monitor must read and understand the operating manual before using this product. In
addition to this operating manual, there are two other manuals available for the gas monitor: "Maintenance
Manual" and "Data Logger Management Program Manual." Contact Riken Keiki if these manuals are
needed.
Throughout this manual, the following indications are used to ensure safe and effective work.
DANGER This message indicates that improper handling may cause serious damage on
life, health or assets.
WARNING This message indicates that improper handling may cause serious damage on
health or assets.
CAUTION This message indicates that improper handling may cause minor damage on
health or assets.
NOTE This message indicates advice on handling.


GX-8000 - 4 -
<Contents>
Preface .................................................................................................................... 3
1 Part Names ............................................................................................................. 5
1-1. Part names (Li-ion battery type) [Standard type] ..................................................... 5
1-2. Part names (Dry battery type) [Option].................................................................... 7
1-3. LCD display ............................................................................................................. 8
2 How to Use.............................................................................................................. 9
2-1. Information for first-time users................................................................................. 9
2-2. Preparation.............................................................................................................. 10
2-3. How to start and exit................................................................................................ 11
2-4. High-concentration combustible gas zero calibration
(TYPE-A and TYPE-E models)................................................................................ 13
2-5. FAIL display ............................................................................................................. 14
2-6. Measurement .......................................................................................................... 15
2-7. End of measurement ............................................................................................... 16
2-8. Explanation of functions (1) ..................................................................................... 18
2-9. Explanation of functions (2) DISPLAY switch .......................................................... 19
2-10. Combustible gas range switching (TYPE-A and TYPE-E models) .......................... 19
2-11. PEAK value display ................................................................................................. 21
2-12. STEL value display.................................................................................................. 22
2-13. TWA value display ................................................................................................... 22
2-14. Alarm test (Full-scale/Alarm setpoint display).......................................................... 23
2-15. Pump OFF............................................................................................................... 23
2-16. Station ID selection.................................................................................................. 24
2-17. Manual memory storage and display....................................................................... 25
2-15. Error (FAIL) display ................................................................................................. 27
2-16. Dedicated battery unit.............................................................................................. 27
3 Alarms ..................................................................................................................... 30
3-1. Alarm types and patterns......................................................................................... 30
3-2. User actions for gas concentration alarms .............................................................. 32
3-3. STEL alarm (short term exposure limit) ................................................................... 32
3-4. TWA alarm (time-weighted average limit)................................................................ 32
4 Maintenance............................................................................................................ 33
4-1. Daily maintenance................................................................................................... 33
4-2. Span adjustment ..................................................................................................... 34
4-3. Sensor replacement ................................................................................................ 34
4-4. Filter replacement.................................................................................................... 34
4-5. Li-ion battery unit or dry battery unit replacement [Option] ...................................... 36
4-6. Consumables .......................................................................................................... 37
5 Troubleshooting....................................................................................................... 38
6 Specifications and Others........................................................................................ 40
6-1. GX-8000 specifications............................................................................................ 40
6-2. Combinations of detected gases by type................................................................. 41
6-3. GX-8000 accessories .............................................................................................. 42

1 Part Names1-1. Part names (Li-ion battery type) [Standard type]
GX-8000 - 5 -
1
Part Names
1-1. Part names (Li-ion battery type) [Standard type]

1 Part Names1-1. Part names (Li-ion battery type) [Standard type]
GX-8000 - 6 -
(1) LCD display: Displays gas concentrations, alarms, etc.
(2) Buzzer sound opening: Emits a buzzer sound to indicate an alarm. (Do not block it.)
(3) Alarm LED arrays: The lamp blinks in response to an alarm.
(4) Infrared communication port: Used to carry out data communications with a PC in data
logger mode.
(5) S/AIR switch: Keep this switch pressed to perform air calibration. See Page
16 for further details.
(6) T/RESET switch: When an alarm occurs, press this switch to reset the alarm.
See Page 16 for further details.
(7) DISPLAY switch: Press this switch to change between display modes. See
Page 16 for further details.
(8) POWER/ENTER switch: Turns on and off the power. See Page 16 for further details.
(9) Gas inlet: Connect a sampling hose to this port.
(10) Gas outlet: Exhausts the gas drawn into the gas monitor. (Do not block it.)
(11) Recharging jack cover: Remove this cover to connect an AC powered charger and
recharge the batteries.
(12) Recharging indicator lamp: Lights up in red during recharging and goes off when
recharging is completed.
(13) Sensor cover: There are sensors inside. May be opened only when the
sensor is to be replaced.
(14) Activated carbon filter knob: Turn this knob to detach and replace the activated carbon
filter.
(15) Battery unit screws: Turn these screws to detach and replace the battery unit.

1 Part Names1-2. Part names (Dry battery type) [Option]
- 7 - GX-8000
1-2. Part names (Dry battery type) [Option]
(1) LCD display: Displays gas concentrations, alarms, etc.
(2) Buzzer sound opening: Emits a buzzer sound to indicate an alarm. (Do not block it.)
(3) Alarm LED arrays: The lamp blinks in response to an alarm.
(4) Infrared communication port: Used to carry out data communications with a PC in data
logger mode.
(5) S/AIR switch: Keep this switch pressed to perform air calibration. See Page
16 for further details.
(6) T/RESET switch: When an alarm occurs, press this switch to reset the alarm.
See Page 16 for further details.
(7) DISPLAY switch: Press this switch to change between display modes. See
Page 16 for further details.
(8) POWER/ENTER switch: Turns on and off the power. See Page 16 for further details.
(9) Gas inlet: Connect a sampling hose to this port.
(10) Gas outlet: Exhausts the gas drawn into the gas monitor. (Do not block it.)
(11) Battery cover: Open and close this cover to replace the batteries. Must be
closed while the gas monitor is in use.
(12) Battery cover fixing screw: Fixes the battery cover.
(13) Sensor cover: There are sensors inside. May be opened only when the
sensor is to be replaced.
(14) Activated carbon filter knob: Turn this knob to detach and replace the activated carbon filter.
(15) Battery unit screws: Turn these screws to replace the dry battery pack.

1 Part Names1-3. LCD display
GX-8000 - 8 -
1-3. LCD display

2 How to Use2-1. Information for first-time users
- 9 - GX-8000
2
How to Use
2-1. Information for first-time users
The gas monitor is used to detect "oxygen-deficient air," "combustible gases," "hydrogen sulfide," and
"carbon monoxide" that may be generated in a manhole, pit, underground premises, hold of a ship, etc.
WARNING
•Do not disassemble the gas monitor or modify or change the circuit or structure, etc.
•Do not connect the sampling hose directly to a location with a pressure higher than the atmospheric
pressure. The internal piping system may be damaged.
•Before use, check that there remains sufficient battery power. When the gas monitor is used for the
first time or is not used for a long period, the batteries may be exhausted.
Either fully recharge the batteries or replace them with new ones before use. (See Pages 22 and 23.)
•Perform gas calibration at fixed intervals.
•Pressing buttons unnecessarily may change the settings, preventing alarms from activating correctly.
Operate the gas monitor using only the procedures described in this operating manual.
•Do not throw the gas monitor into fire.
•Do not use the gas monitor at higher temperatures, humidities, and pressures or at lower
temperatures than the specified range. Normal displays and operations may be prevented.
•Do not store the gas monitor in a place exposed to direct sunlight or in a sun-heated car. Normal
displays and operations may be prevented.
•Do not use the gas monitor near a device or equipment that emits strong electromagnetic waves.
•Do not drop or give shock to the gas monitor by, for example, relocating the gas monitor with a water
trap, an optional accessory, attached. The gas inlet may be damaged.

2 How to Use2-2. Preparation
GX-8000 - 10 -
2-2. Preparation
(1) Packing check
After opening the package, check the gas monitor and accessories.
If anything in the following list is not included, contact the dealer or Riken Keiki.
Gas monitor GX-8000 and Li-ion battery pack AC powered charger (only for recharging type)
Gas sampling probe Gas sampling hose
Shoulder strap Operating manual
Test certificate
(2) Recharging Li-ion batteries or putting dry batteries
1) Li-ion batteries [Standard type]
When the gas monitor is used for the first time, use the provided AC powered charger to recharge
the batteries. (See Page 22.)
2) Dry batteries type [Option]
When dry batteries are used, put dry batteries in the battery pack. (Three AA alkaline batteries)
(See Page 23.)
(3) Checking connection of the sampling hose
Connect the sampling hose (spiral hose) securely to the gas inlet of the unit.
Attach the gas sampling probe to the end of the sampling hose.
Connect the sampling hose to GAS IN until it
clicks into place.
CAUTION
•Use only a sampling hose specified by Riken Keiki.
•Use the gas monitor with all of the gas sampling probe, gas
sampling hose (with a float probe), filter tube, etc. connected
so that no foreign matter is drawn into the sampling hose.
•Connect a gas sampling probe and a sampling hose by
fastening them manually without using any tool. If they are
fastened too tightly using a tool, the plastic part of the gas
sampling probe may be broken.

2 How to Use2-3. How to start and exit
- 11 - GX-8000
2-3. How to start and exit
Keep the POWER/ENTER switch pressed for three seconds or more to turn on the power.
After conducting self diagnosis on power voltage, sensor connection, flow rate and other operations and
functions, the gas monitor enters gas detection mode.
Steps 1. Power-on →Warm-up →Gas concentration reading on the display screen
→2. Measurement →3. Power-off

2 How to Use2-3. How to start and exit
GX-8000 - 12 -
The operation after power-on is as follows:

2 How to Use2-4. High-concentration combustible gas zero calibration (TYPE-A and TYPE-E models)
- 13 - GX-8000
2-4. High-concentration combustible gas zero
calibration (TYPE-A and TYPE-E models)
The models that can display combustible gas levels in two ways, "%LEL range" and "vol% range," need
zero calibration using a base gas in order to measure the "vol% range" concentration correctly.
(1) Fill a sampling bag with a base gas (such as N2 and an inert gas).
(2) In a measurement screen, keep the T/RESET switch pressed and press the DISPLAY switch.
Press either the ▲/AIR or T/RESET switch and select VOL Z.CAL.
Zero Point Calibration Screen
(3) Press the POWER/ENTER switch once. The screen is changed to O2 and vol% display and VOL
Z.CAL blinks in the lower row.
Connect the sampling bag containing a base gas to the gas inlet (GAS IN). When the reading is
stabilized, press the POWER/ENTER switch.
(4) When END is displayed, the calibration has been successfully completed. Remove the sampling bag
from the gas inlet.
(5) When FAIL is displayed, the calibration means to be failed.
WARNING
Perform AIR calibration in fresh air.
CAUTION
In a location with sudden temperature changes over 15 degrees centigrade, let the gas monitor stand for
about 10 minutes before performing AIR calibration.
Introduction of the base gas ⇒
Blinkin
g
Blinkin
g
[If calibration failed at an oxygen concentration of 8% or higher]
Press the T
/
RESET switch to reset the error.

2 How to Use2-5. FAIL display
GX-8000 - 14 -
(6) After successful completion of calibration, press the S/AIR or T/RESET switch. When ESCAPE is
displayed, press the POWER/ENTER switch.
(7) The measurement screen is displayed again.
2-5. FAIL display
In normal operation, the screen display changes as shown in the previous section until the gas monitor is
ready for measurement. However, the LCD display screen shows "FAIL" as shown in the following figure if
the self diagnostic function detects an error in the gas monitor before or during measurement. See Page 22
for other FAIL displays and explanation of them.
FAIL display examples
←AIR calibration failed
AIR calibration failed. Press the RESET switch.
If AIR calibration fails again, contact the dealer or Riken Keiki
headquarters or authorized local representative.
←Battery voltage low
The battery voltage is insufficient.
Either recharge or replace the batteries.
←Sensor abnormality
Detection is not possible due to a sensor abnormality. The failed
sensor name is displayed together with FAIL SENSOR. [The display
example shows "CO."]
If this display is shown, request the dealer or Riken Keiki
headquarters or authorized local representative to perform a
maintenance on the gas monitor.
←VOL% zero calibration failed (only TYPE-A and TYPE-E models)
Displayed to indicate a failure in zero point calibration for
high-concentration combustible gas measurement.
Press the RESET switch to reset the error.
Calibration will be successful when the oxygen is less than 8%.
Zero Point Calibration Screen
S/AIR or T/RESET switch
Press the POWER/ENTER switch.

2 How to Use2-6. Measurement
- 15 - GX-8000
2-6. Measurement
(1) Measurement method
Bring the gas sampling probe or float probe to the measurement location and read the LCD
measurement display when it stabilizes.
Display example
←
Display example
CH4concentration: 0%LEL
O2concentration: 20.9%
CO concentration: 0 ppm
H2S concentration: 0 ppm
Time: 9:30
Battery level: Full
DANGER
While conducting measurement in a manhole or confined space, do not lean over or look into the manhole or
closed space. It may lead to dangers because oxygen-deficient air or other gases may blow out.
WARNING
•Do not block the buzzer sound hole. No alarm sound can be heard.
•If an oxygen deficiency or toxic gas (CO or H2S) alarm occurs, evacuate the area.
After taking safety precautions, take appropriate actions such as introducing fresh air and sealing the
generation source.
•Do not connect the sampling tube directly to a location with a pressure higher than the atmospheric
pressure. The internal piping system may be damaged.
•If a low battery alarm occurs, gas detection cannot be conducted. If the alarm occurs during use, turn
off the power and promptly recharge the batteries in a non-hazardous area.
CAUTION
•Do not measure anything but air, combustible gases, or a mixture of vapors and toxic gases.
•Do not place the gas monitor where water or dirt gets accumulated. The gas monitor placed at such a
location may malfunction due to water or dirt that gets into the buzzer opening, gas inlet, etc.
•The gas inlet and outlet of the gas monitor are not water-proof. Be careful not to let water get into
these parts.
•Do not draw in rainwater or other water. Because this may cause trouble and gas cannot be detected.
•Do not drop or give shock to the gas monitor. The water-proof and explosion-proof properties and
accuracy may be deteriorated.
•In a low-temperature environment, the operating time is shortened due to the battery performance property.
•When using this gas monitor in a hazardous area, take the following countermeasures for preventing
dangers resulting from electrostatic charges.
(1) Wear anti-static clothes and conductive shoes (anti-static work shoes).
(2) For indoor use, use the gas monitor while standing on a conductive work floor (with a leakage
resistance of 10 MΩor less).
•Do not use the gas monitor while recharging it.
•If the combustible gas reading exceeds 100% LEL, the CO reading rises temporarily but this is not an
abnormality.

2 How to Use2-7. End of measurement
GX-8000 - 16 -
NOTE
•The gas monitor, being compliant to IP67, is not water-pressure-resistant. Do not use the gas monitor where a
high water pressure is applied to it (under a faucet, shower, etc.) or submerge it under water for a long time.
•Do not wash the gas monitor in a washing machine or ultrasonic cleaner.
•At a low temperature, the response of the LCD display may get slow down.
(2) Precautions on operating environment
Whereas the gas monitor can detect oxygen, combustible gases, hydrogen sulfide, and carbon
monoxide, the measurement environment may include gases that have harmful effects on the sensors
of this unit.
The gas monitor cannot be used in the presence of the following gases:
1) Sulfides (such as H2S and SO2) continuously existing in high concentrations
2) Halogen gases (such as chloride compounds and chlorofluorocarbons)
3) Silicone (Si compounds)
Note that drawing in dirty water, dust, metallic powder, etc. will significantly deteriorate the sensor
sensitivities. Be careful when the gas monitor is used in an environment where these elements exist.
2-7. End of measurement
Make the gas monitor draw in fresh air. After the display resets to zero (or 20.9% for oxygen), keep the
POWER/ENTER switch pressed until the power is turned off.
If the power is turned off before the display resets to zero (or 20.9% for oxygen), only the pump may operate
(for 30 seconds at the longest).
WARNING
•Do not use the gas monitor in the presence of the above gases (such as sulfides, halogen gases,
and silicone), which may shorten the sensor life significantly or cause malfunctions such as
inaccurate readings.
•In case the gas monitor is used for detection in the presence of silicone, etc., be sure to check the gas
sensitivities before using it again.
•Do not submerge the gas monitor in a liquid other than water. The gas monitor is water-proof only in
fresh water and running water, and not in hot water, salt water, detergent, chemicals, human sweat, etc.
•Do not jab the buzzer opening with a sharp-pointed item. The unit may malfunction or get damaged,
allowing water or foreign matter, etc. to get inside.
•Do not affix a label on the infrared port. Infrared communications can no longer be conducted.
Count-down

2 How to Use2-7. End of measurement
- 17 - GX-8000
When stored or not in use for a long time, the gas monitor shall be kept under the following environmental conditions:
(1) In a dark place under the normal temperature and humidity away from direct sunlight
(2) In a place where gases, solvents or vapors are not present
Store the gas monitor in a shipping carton, if any, in which the product was delivered.
Store the gas monitor in a plastic bag if the shipping carton is not available.
Store the gas monitor away from dust, etc. if the shipping carton is not available.
CAUTION
•When the gas monitor is contaminated, clean it with a dustcloth, etc. after wetting it in water and
wringing it out well.
•When cleaning the gas monitor, do not splash water over it or use organic solvents such as alcohol
and benzene on it. The surface of the gas monitor may be discolored or damaged.
•When the gas monitor gets wet, water may remain in the buzzer sound opening or clearances.
Drain water as follows:
1. Wipe away moisture on the gas monitor thoroughly using a dry towel, cloth, etc.
2. While holding the gas monitor firmly, shake it about ten times with the buzzer sound opening
facing downward.
3. Wipe away moisture coming out from the inside thoroughly using a towel, cloth, etc.
4. Place the gas monitor on a dry towel, cloth, etc. and let it stand at normal temperatures.
CAUTION
•If the gas monitor is not used for a long time, turn on the power at least once every six months and
check that the pump draws in air.
The gas monitor, when not activated for a long time, may cease to work because of hardening of the
grease in the pump motor.

2 How to Use2-8. Explanation of functions (1)
GX-8000 - 18 -
2-8. Explanation of functions (1)
The gas monitor offers various functions. The functions can be called up using the switches.
WARNING
Pressing buttons unnecessarily may change the settings, preventing alarms from activating correctly.
Operate the gas monitor using only the procedures described in this operating manual.
CAUTION
•Press the S/AIR switch after checking that a fresh air is present in the surroundings.
•If AIR calibration fails due to a sensor abnormality, a message appears, indicating which sensor failed.
•Do not remove the panel sheet on the LCD display and operation panel. The water-proof and
dust-proof performances will be deteriorated.
(1) S/AIR switch
Press the S/AIR switch to reset the
readings to zero if incorrect readings
are displayed at power-on or during
measurement when there is no gas in
the surroundings. (The oxygen level is
reset to 20.9%.)
(2) DISPLAY switch
Press the DISPLAY switch to change the display screen,
check data, and change settings.
(1) Combustible gas range setting, (2) PEAK value display,
(3) STEL value display, (4) TWA value display, and
(5) Full-scale/Alarm setpoint display
The gas monitor, if not operated
for 20 seconds in any of these
modes, automatically reverts to
the measurement mode.
(3) T/RESET switch
Press the T/RESET switch to reset a
gas concentration alarm or other alarm
that has occurred after checking it.
(4) POWER/ENTER switch
Press the POWER/ENTER switch to
turn on or off the power, change the
settings, etc.

2 How to Use2-9. Explanation of functions (2) DISPLAY switch
- 19 - GX-8000
2-9. Explanation of functions (2) DISPLAY switch
Press the DISPLAY switch to display various screens. (Figures in the following displays are examples)
1. Combustible gas range setting 2. PEAK value display 3. STEL value display
4. TWA value display 5. Full-scale/Alarm setpoint
display
6. Pump OFF
7. Station ID selection 8. Manual memory display
2-10. Combustible gas range switching (TYPE-A and
TYPE-E models)
The models that can display combustible gas levels in two ways, "%LEL range" and "vol% range,"
automatically switch between these two displays according to the gas concentration, from "%LEL range" to
"vol% range" and vice versa.
(1) During vol% range measurement, "vol%" and "No ALARM" displays blink.
(2) If the reading is 3 vol% or less and the oxygen concentration is 19.5% or more during vol% range
measurement, keep the RESET switch pressed to forcibly change the display to the %LEL range.
VOL% range measurement %LEL range measurement

2 How to Use2-10. Combustible gas range switching (TYPE-A and TYPE-E models)
GX-8000 - 20 -
(3) Measurement fixed to the vol% or %LEL range
1) Press the DISPLAY switch once.
2) Press the POWER/ENTER switch to change the setting.
Press the DISPLAY switch if you choose not to change the setting.
3) Press the S/AIR or T/RESET switch. When ONLY VOL or ONLY LEL is displayed, press the
POWER/ENTER switch.
4) When END is displayed, the change is completed.
5) Press the DISPLAY switch seven times to return to the measurement screen.
(4) Switching the vol% or %LEL range back to the automatic range
1) Press the DISPLAY switch once.
2) Press the POWER/ENTER switch to change the setting.
Press the DISPLAY switch if you choose not to change the setting.
3) Press the S/AIR or T/RESET switch. When AUTORANG is displayed, press the POWER/ENTER
switch.