background image

2-2

SAFETY 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.

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.

Summary of Contents for VT770 Series

Page 1: ... Projector SERVICE MANUAL SUPPLEMENT Better Service Better Reputation Better Profit Optical alignment jig optical axis alignment polarizer alignment SAFETY CAUTION Before servicing this chassis it is important that the service technician read and follow the Safety Precautions and Product Safety Notice in this Service Manual WARNING SHOCK HAZARD Use an isolation transformer when servicing NEC DISPL...

Page 2: ...IN DE REDUIRE LES RISQUES D ELECTROCUTION NE PAS DEPOSER LE COUVERCLE IL N Y A AUCUNE PIECE UTILISABLE A L INTERIEUR DE CET APPAREIL NE CONFIER LES TRAVAUX D ENTRETIEN QU A UN PERSONNEL QUALIFIE Ce symbole a pour but de prévenir I utilisateur de la présence d une tension dangereuse non isolée se trouvant à l intérieur de l appareil Elle est d une intensité suffisante pour constituer un risque d él...

Page 3: ...ge parts and if removed for servicing they must be retuned precisely to their original positions 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 u...

Page 4: ... Extension connector Connector PWB for extension No Part No Description Number of pins Photo Wire length 1 9N9CN001 CONNECTOR 2P 900 2P connector 900mm 2 9N9CN002 CONNECTOR 3P 900 3P connector 900mm 3 9N9CN003 CONNECTOR 4P 900 4P connector 900mm 4 9N9CN004 CONNECTOR 5P 900 5P connector 900mm 5 9N9CN005 CONNECTOR 2P 300 2P connector 300mm 6 9N9CN006 CONNECTOR 3P 400 3P connector 400mm 7 9N9CN007 CO...

Page 5: ... 9N9FFC03 CABLE FFC 30P 600 30P connector 600mm 17 9N9FFC04 CABLE FFC 32P 600 32P connector 600mm 18 7N500019 CABLE FFC 36P 600 36P connector 600mm 19 9N9FFC06 CABLE FFC 40P 600 40P connector 600mm 13 9N9FFC07 CABLE FFC 57P 600 57P connector 600mm 20 9N9M0001 RELAY PWB 2P 2P PWB 21 9N9M0002 RELAY PWB 3P 3P PWB 22 9N9M0003 RELAY PWB 4P 4P PWB 23 9N9M0004 RELAY PWB 5P 5P PWB 24 9N9M0005 RELAY PWB 15...

Page 6: ...P 13P PWB 26 9N9M0007 RELAY PWB 24P 24P PWB 27 9N9M0008 RELAY PWB 30P 30P PWB 28 9N9M0009 RELAY PWB 32P 32P PWB 29 9N9M0010 RELAY PWB 36P 36P PWB 30 9N9M0011 RELAY PWB 40P 40P PWB 31 9N9M0012 RELAY PWB 18P 18P PWB 32 9N9M0013 RELAY PWB 57P 57P PWB 33 9N9M0014 RELAY PWB 16P 16P PWB ...

Page 7: ...e optical axis alignments by means of a dummy load In the future please make optical axis alignments with the use of the extension connector and the extension connector PWB in the same manner as for the polarizer alignments The method of connection to make optical axis alignments with the use of the extension connector and the extension connector PWB is the same as for the polarizer alignment This...

Reviews: