Fluke 433 - Page 64

Fluke 433, 434, 435
Service Manual
5-8
5.2.7 Replacing the LCD Window/Decal
The LCD window/decal (Figure 5-6, item 2) is glued on the top cover. To replace it do
the following:
1. From the inside of the top cover push the window outwards until it comes of.
2. Carefully remove remains of glue from the top cover. The bulk of the glue can be
removed with sticky tape. This action must be completed by cleaning the surface
with alcohol. A clean surface assures a well-closed cabinet after installation of the
new window.
This is an important safety issue!
3. Remove the protection foil from the new window
4. Firmly press the new window on the top cover.
5.2.8 Removing the Keypad and Keypad Foil
Caution
To avoid contaminating the keypad contacts, and the keypad
foil contacts with oil from your fingers, do not touch the
contacts (or wear gloves). Contaminated contacts may not
cause immediate instrument failure in controlled environments.
Failures typically show up when contaminated units are
operated in humid areas.
Referring to Figure 5-6, use the following procedure to remove the keypad and the
keypad foil.
1. Remove the display assembly (see Section 5.2.6).
2. Remove the keypad support plate item 5.
3. Remove the keypad foil item 4. Notice the keypad foil positioning pins in the top
case when reassembling.
4. Remove the keypad item 3.
5.2.9 Disassembling the Main PCA Unit
Caution
To avoid contaminating the main PCA with oil from your
fingers, do not touch the contacts (or wear gloves). A
contaminated PCA may not cause immediate instrument failure
in controlled environments. Failures typically show up when
contaminated units are operated in humid areas.
Referring to Figure 5-8, use the following procedure disassemble the main PCA unit.
1. Unscrew the seven M3x8 Torx screws (items 8,10) that secure the shielding covers
(item 7 and 9), and remove the shielding covers. The covers are interlocking
2. Unscrew four M3x16 standoffs (item 4) and one M3x12 standoff (item 3) that secure
the PCA to the shielding box item 2.
3. Remove the PCA from the shielding box.
4. To separate the Input block (item 1) from the PCA, unsolder 5 + 8 leads from the
PCA. Then separate the input block from the PCA. The input block is locked with 4
studs that fit into 2 holes in the PCA and 2 holes in the bottom case.