Tektronix LumaColor II J18, Instruction Manual

Page: 71 / 114

Troubleshooting
J18 Photometer Instruction Manual 6–5
The A1 Board
Most functions of the J18 are located on the A1 board. Checking the
Power Supply, later in this section, will allow you to determine
whether there is a power supply problem.
The A2 Display Board
The A2 Display board is probably at fault if:
H
segments of the display are missing
H
the backlight does not operate
To check the display, power on the J18 without a sensor head
attached, and note whether all segments of the display are activated.
If the entire display is inactive, or if the backlight does not operate,
proceed to Checking the Power Supply to rule out a problem with the
power supply.
Checking the Power Supply
To check the power supply, you will need:
H
3
/
32
inch hex wrench
H
Pozidriv

screwdriver
H
a voltmeter (for voltages in the range 0 to 15 V)
H
Nine-volt, IEC 6LR61-type alkaline battery
1. Remove the battery from the battery compartment.
CAUTION. Do not apply power to the J18 while disassembling it.
Damage to the A2 board could result.
Static electricity can damage the circuit boards of the J18. Observe
static precautions when the covers of the J18 are removed.
2. Using the hex wrench, remove the four screws from the J18 front
panel.
3. Remove the back cover of the J18.
Troubleshooting
J18 Photometer Instruction Manual 6–5
The A1 Board
Most functions of the J18 are located on the A1 board. Checking the
Power Supply, later in this section, will allow you to determine
whether there is a power supply problem.
The A2 Display Board
The A2 Display board is probably at fault if:
H
segments of the display are missing
H
the backlight does not operate
To check the display, power on the J18 without a sensor head
attached, and note whether all segments of the display are activated.
If the entire display is inactive, or if the backlight does not operate,
proceed to Checking the Power Supply to rule out a problem with the
power supply.
Checking the Power Supply
To check the power supply, you will need:
H
3
/
32
inch hex wrench
H
Pozidriv

screwdriver
H
a voltmeter (for voltages in the range 0 to 15 V)
H
Nine-volt, IEC 6LR61-type alkaline battery
1. Remove the battery from the battery compartment.
CAUTION. Do not apply power to the J18 while disassembling it.
Damage to the A2 board could result.
Static electricity can damage the circuit boards of the J18. Observe
static precautions when the covers of the J18 are removed.
2. Using the hex wrench, remove the four screws from the J18 front
panel.
3. Remove the back cover of the J18.