NEC VT440 Service Manual page 4
Hide thumbs
Also See for VT440:
- User manual (42 pages) ,
- Installation data (8 pages) ,
- Specifications (2 pages)
Table of Contents
Advertisement
SAFTY PRECAUTIONS
During servicing carefully observe the following.
1. OBSERVE ALL PRECAUTIONS
Items and locations that require special care during serv-
icing, such as the cabinet, chassis, and parts are labelled
with individual safety instructions. Carefully comply with
these instructions and all precautions in the instruction
manual.
2. BE CAREFUL OF ELECTRIC SHOCK
The chassis carries an AC voltage. If you touch the
chassis while it is still alive, you will get a severe shock.
If you think the chassis is alive, use an isolating
transformer or gloves, or pull out the plug before
replacing any parts.
3. USE SPECIFIED PARTS
The components have been chosen for minimum
flammability and for specific levels of resistance value
and withstand voltage. Replacement parts must match
these original specifications. Parts whose specifications
are particularly vital to safe use and maintenance of the
set are marked
on the circuit diagrams and parts list.
Substitution of these parts can be dangerous for you
and the customer, so use only specified parts.
4. REMOUNT ALL PARTS AND RECONNECT ALL
WIRES AS ORIGINALLY INSTALLED
For safety, insulating tape and tubes are used
throughout, but some lift-off parts on the printed wiring
board require special attention.
All wires are positioned away from high-temperature and
high-voltage parts, and, if removed for servicing, they
must be retuned precisely to their original positions.
2-2
5. LAMP
Be very careful of the lamp because it generates high
heat while it is used at high voltage. When replacing
the bulb, make sure it is cool enough.
6. LENS
Do not look into the lens during projection. This important
to avoid damage to the eyes.
7. SERVICING
At the time of repair or inspection services, use an earth
band (wrist band), without fail.
8. RUN A COMPLETE SAFETY CHECK AT THE
COMPLETION OF SERVICING
After completion of servicing, confirm that all screws,
parts, and wiring, removed or disconnected for servicing,
have been returned to their original positions. Also
examine if the serviced sections and peripheral areas
have suffered from any deterioration as a result of
servicing. In addition, check insulation between external
metallic parts and blades of wall-outlet plugs. This
examination is indispensable in confirming complete
establishment of safety.
(Insulation check)
Pull out a plug from a wall outlet to disconnect the
connection cable. Then turn on the POWER switch.
Use a 500V megger (Note 2) and confirm that the
insulation resistance is 1MΩ or more between each
terminal of the plug and exposed external metal (Note
1). If the measured value is below the specified level,
then it is necessary to inspect and fix the set.
(Note 1)
Exposed external metal....RGB input terminals, control
terminals, etc.
(Note 2)
If a 500V megger is not available for an unavoidable
reason, then use a circuit tester or the like for inspection.
- Quick Links:
- Lcd Projector
- Power/ Status Light Messages
Hide quick links:
Advertisement
Chapters
Table of Contents
Troubleshooting
