Tektronix LumaColor II J18, Instruction Manual

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Troubleshooting
6–4 J18 Photometer Instruction Manual
H
Operating the sensor-head in contact with the surface is not
recommended, because reflections may occur between the front
surface of the head and the surface to be measured. Placement of
the head too close to the surface may also cause shadowing.
The light shield or suction cup provides adequate spacing
between the head and the surface to prevent reflection on
backlighted surfaces.
If measurements are still incorrect, the sensor head may require
recalibration. Contact your Tektronix representative.
Board-level Troubleshooting
The two circuit boards in the J18 may be replaced. If the J18 does
not function, you can use these procedures to isolate the problem to
one of the boards. Refer to Replaceable Parts for ordering informa-
tion.
CAUTION.
The following servicing instructions are for use by
qualified service personnel only. Once the covers of the J18 are
removed, the instrument could be damaged.
Most functions of the J18 are located on the A1 board. The A2
Display board controls the display, backlight, and keyboard. The
general troubleshooting sequence for the J18 is:
1. Verify that the problem is not covered in Basic Troubleshooting.
2. Check for a display, backlight, or keyboard problem (indicating
the A2 board). If there appears to be a display problem, also
check the power supply on the A1 board, which could be at fault.
3. Other problems are due to the A1 board. If a power supply
problem is suspected, perform the procedure in Checking the
Power Supply to verify that the power supply, and not the battery,
is at fault.
Troubleshooting
6–4 J18 Photometer Instruction Manual
H
Operating the sensor-head in contact with the surface is not
recommended, because reflections may occur between the front
surface of the head and the surface to be measured. Placement of
the head too close to the surface may also cause shadowing.
The light shield or suction cup provides adequate spacing
between the head and the surface to prevent reflection on
backlighted surfaces.
If measurements are still incorrect, the sensor head may require
recalibration. Contact your Tektronix representative.
Board-level Troubleshooting
The two circuit boards in the J18 may be replaced. If the J18 does
not function, you can use these procedures to isolate the problem to
one of the boards. Refer to Replaceable Parts for ordering informa-
tion.
CAUTION.
The following servicing instructions are for use by
qualified service personnel only. Once the covers of the J18 are
removed, the instrument could be damaged.
Most functions of the J18 are located on the A1 board. The A2
Display board controls the display, backlight, and keyboard. The
general troubleshooting sequence for the J18 is:
1. Verify that the problem is not covered in Basic Troubleshooting.
2. Check for a display, backlight, or keyboard problem (indicating
the A2 board). If there appears to be a display problem, also
check the power supply on the A1 board, which could be at fault.
3. Other problems are due to the A1 board. If a power supply
problem is suspected, perform the procedure in Checking the
Power Supply to verify that the power supply, and not the battery,
is at fault.