Fluke 87 Series IV, Руководство по обслуживанию

Страница: 20 / 38

87 & 89 Series IV
Service Manual
12
Basic Maintenance
Warning
To avoid electrical shock or personal injury, remove the test
leads and any input signals before opening the case or
replacing the battery or fuses. To prevent damage or injury,
install ONLY batteries or fuses specified for this product.
Opening the Meter Case
Caution
To avoid unintended circuit shorting, always place the
uncovered Meter assembly on a protective surface. When the
case of the Meter is open, circuit connections are exposed.
To open the Meter case, do the following:
1. Disconnect test leads from any live source, turn the rotary switch to
OFF
, and remove
the test leads from the front terminals.
2. Remove the battery door by using a flat-blade screwdriver to turn the battery door
fasteners 1/4-turn counterclockwise.
3. The case bottom is secured to the case top by four screws, one at each corner.
Remove the screws with a Phillips-head screwdriver.
4. Pull the two halves of the case apart.
Removing and Reinserting the Circuit Board Assembly
The circuit board assembly must be removed to access and replace the LCD.
Caution
The circuit board is extremely susceptible to contamination.
Handle it by the input receptacle, fuse clips or edges of the
board only. You can use clean surgical gloves to help avoid
contamination.
1. Open the Meter case and remove the case bottom to access the circuit board.
2. Remove the two Phillips-head screws securing the circuit board to the case top and
lift it out carefully to avoid contamination.
3. To reinsert the circuit board, simply place it into the case top with the LCD display
showing through the window.
4. Carefully replace the two Phillips-head screws that connect the circuit board to the
case top.
Caution
Do not over-torque the two Phillips-head screws when you
reconnect the circuit board to the case top. Doing so may
create shielding problems and cause the Meter to give incorrect
readings.