Infocus projector no power

Discussion in 'The Projects Forum' started by 1-3-2-4, May 13, 2013.

  1. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
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    It's the IN116 model

    I have the power supply out right now and with a power cable plugged in I see no voltage over the main fuse.


    Where should I check first?

    the stuff on the heatsink

    k20a60u & fsu10a60 and the bridge rectifier D10XB60b
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    What do you mean by "I see no voltage over the main fuse"?
    Do you see AC power at both ends of the fuse with respect to AC Neutral?
     
  3. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
    No I don't see any voltage that way
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    Then check your power cable.
     
  5. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
    power cable is fine.. I was saying that I was getting voltage on the bridge rectifier 164V But between the neutral and other end of the fuse I get nothing.
     
  6. MrChips

    Moderator

    Oct 2, 2009
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    Which fuse?

    The AC fuse is the first place the AC live should be connected to.

    Did you check the obvious - the fuse?
     
  7. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1

    I checked it with the meter and it's good, that's what I don't understand.. on the board the fuse connects between Line & neutral
     
  8. MrChips

    Moderator

    Oct 2, 2009
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    That's not right.

    A fuse connected between Live and Neutral will blow as soon as AC power is applied.

    Do you have your meter set to AC voltage?
    You should see AC line voltage at both ends of the fuse with respect to NEUTRAL.
     
  9. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1

    Doh! forgot to switch the meter! I see 120V on the fuse
     
  10. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
    I'm going down the line and it seems 164 V is kind of low? It seems like it might be something in the middle part of the board? It has two transformers but I'm not sure what the voltage should be.
     
  11. MrChips

    Moderator

    Oct 2, 2009
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    That is a SMPS (switched mode power supply) and there are some very lethal voltages in there. I would not be messing around if you don't know what you are doing.

    One rule to follow when working with high voltage circuits - Put one hand in your pocket!!!

    Some SMPS will not operate when disconnected from the load.
     
  12. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
    I'm very well aware of the voltages, the voltages on the transformer side is low like 4V or so for the first set.

    Does not help you really have no info what-so-ever about the board.
     
  13. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
  14. wayneh

    Expert

    Sep 9, 2010
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    IMHO, you're wasting your time without a service manual and/or schematic. For all we know, the power supply is fine but might be under control of another module.
     
  15. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
    at the very best it should provide standby power.. I think its one of the caps, infocus is noted for them going out and providing no power at all.

    Its easy to just give up and throw it under the rug.
     
  16. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
    MR4010 IC seems like the gate is stuck on and conducting which would account for it going to 60 C in less then 3 minutes with no load.

    I will have to get a replacement and check.
     
  17. wayneh

    Expert

    Sep 9, 2010
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    Seems worth a try. Good luck.
     
    1-3-2-4 likes this.
  18. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
    Thanks, the painful part is waiting since the only sellers were in China and Malaysia.
     
  19. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
    No change btw so yeah, the replacement the leads were spaced more apart.. so you know I made sure before I pulled the first one to pre-bend the leads.. So I go and show this person and they are like No you have the pins wrong, they only bend forward and backwards and not sideways.. So they are pretty much saying me and Infocus hooked it up wrong... ha

    So being as the last two pins are source and drain, what bad could happen so I can prove him wrong, trust me I counted and checked the pins before I bent them
    [​IMG]
    [​IMG]
    [​IMG]
     
  20. 1-3-2-4

    Thread Starter Active Member

    Dec 26, 2008
    194
    1
    I was looking at a SMPS pdf repair guide and so when checking the PFC which is on the underside of the board I should be checking between VCC and the filter cap? and backtrace, and when I find no voltage that will be my sign of what's wrong?
     
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