1. Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
    Dismiss Notice

LCD Power Supply

Discussion in 'Repairing Electronics' started by karyoker, May 23, 2009.

  1. RosaCar

    RosaCar New Member

    Joined:
    Aug 2, 2009
    Messages:
    7
    Likes:
    0
    Same board, different problem

    Hi everyone,
    I just signed up for this board. 3 days ago my MAG 32in lcd tv distorted & the lcd shut off. The sound was still on. Now, when I turn it on, it shows the loading screen for a second (with a deeper black bar in the center) and shuts off. The sounds still plays. I am thinking it is a power issue. I have the same power board as this one (I believe this is the one this topic is about)
    http://cabaret-karaoke.com/pol/ps.jpg
    I would love to know what I need to do to get this up and running again. I can post pictures of the board if need be. I noticed a lot of cold solder as well as evidence of resoldering/work by hand previously. I would be greatly in your debt if any of you can help me. I am dying without TV!
     
  2. jetstream

    jetstream New Member

    Joined:
    Jul 23, 2009
    Messages:
    17
    Likes:
    0
    techy_not, Any luck yet with your PSB?
     
  3. techy_not

    techy_not New Member

    Joined:
    Jul 27, 2009
    Messages:
    18
    Likes:
    0
    Nope adsolutely no lick. i testing almost every component on there so i am thinking its an IC problem. I wish i could find a real technician who could troubleshoot at the component leve. where i am from on the islands i know a guy who would fix this in a day but now live in the US and it would be too much to send it back home to get fixed.. Any luck with yours.
     
  4. dave

    Dave New Member

    Joined:
    Jan 12, 1997
    Messages:
    -
    Likes:
    0


     
  5. jetstream

    jetstream New Member

    Joined:
    Jul 23, 2009
    Messages:
    17
    Likes:
    0

    No luck on this side either, i am not good at testing electronics, but if I can find the schematic for our board, I know a friend who can fix it.
    I will keep you posted.
     
  6. techy_not

    techy_not New Member

    Joined:
    Jul 27, 2009
    Messages:
    18
    Likes:
    0
    Well good luck on finding it. I will try to search for it tomorrow.
     
  7. mu2

    mu2 New Member

    Joined:
    Aug 18, 2009
    Messages:
    1
    Likes:
    0
    Does anyone know who stocks the FCPF18N60 mosfet used in the Polaroid 323B power supply? Digikey and Mouser list a 18N60 but don't stock them.
    Thanks for your help.
     
  8. mneary

    mneary New Member

    Joined:
    Feb 27, 2007
    Messages:
    4,502
    Likes:
    67
    Location:
    California USA
    Digikey doesn't stock every MOSFET; I've noticed they often leave out some of the lower currents or voltage ratings in a product line. For example, they don't stock 18N60 but they do stock 22N60, 26N60, and 30N60.

    It would be extremely likely that 22N60 would work in place of the 18N60.
     
  9. tvjoe

    tvjoe New Member

    Joined:
    Aug 21, 2009
    Messages:
    8
    Likes:
    0
    Location:
    Fort myers fl
    Techy-not. Could you supply contact info for polaroid parts deal. $122.00 sounds good to me.I have same problem with power supply . mine seems to have open primary on one of the transformers. Thanks for any info TvJoe.
     
  10. KeithU

    KeithU New Member

    Joined:
    Jul 16, 2009
    Messages:
    7
    Likes:
    0
    I'd like that contact info, too, please.

    Tvjoe, if you're in Fort Myers, I'm dang close to you, if having access to my power supply would help you troubleshoot yours. Mine has no 5V on the standby pin, but other than replacing some caps, I haven't been able to troubleshoot why. Not sure how a known bad PS might help you, but if you want I'll be happy to let you borrow it.
     
  11. tvjoe

    tvjoe New Member

    Joined:
    Aug 21, 2009
    Messages:
    8
    Likes:
    0
    Location:
    Fort myers fl
    Power supply module polaroid

    Keithu. I found a working one i hope! Havent rec yet. I would love to know what prob is. Checked everything i could think of. Thanx TvJoe.
     
  12. KeithU

    KeithU New Member

    Joined:
    Jul 16, 2009
    Messages:
    7
    Likes:
    0
    Great, Joe, I hope that works out. No progress here, with mine - you wouldn't happen to still have a shop, would you?
     
  13. tvjoe

    tvjoe New Member

    Joined:
    Aug 21, 2009
    Messages:
    8
    Likes:
    0
    Location:
    Fort myers fl
    Polaroid power supply

    Keithu no got rid of store fronts years ago. Still like to repair keeps me out of the bar few hours a day retired. Hooked up external 5v to mod back lights fire but thats all now really wondering. all v their will post if breakthru. Thanx TvJoe.
     
  14. Agustín

    Agustín New Member

    Joined:
    Sep 20, 2009
    Messages:
    4
    Likes:
    0
    Location:
    Mexico City
    Hey, can somebody help me? just tell me the numbers on big and small, thank you
     

    Attached Files:

    Last edited: Sep 20, 2009
  15. JD19

    JD19 New Member

    Joined:
    Nov 18, 2009
    Messages:
    11
    Likes:
    0
    I have a FLM-232B. Power supply is bad also (it is a 00 model, so it has the yellow/orange power supply and not the black one). I get the red LED to light when I plug it in (standby mode), then when I turn it on the LED turns blue ( On mode) but no picture.
    I have 24V on CN3 pin 4,5 and 6. CN3 pin 7 is 0V in standby and 5V when it's on. I think this is all correct. The 24V is routed to the control board in standby and that is where the 5V comes from when you turn it on. When 5V is routed back to the power supply via CN3 pin 7, it should switch the other half/part of the power supply on and through CN2. That is how I think it is suppose to work.
    My problem is that the other part of the power supply never turns on and I get no voltage on CN2. I'm not sure what that voltage should be.

    Can anyone confirm this? Thanks in advance.
     
  16. jomede

    jomede New Member

    Joined:
    Dec 2, 2009
    Messages:
    10
    Likes:
    0
    Flm-323b

    Can someone point out the pins everyone is describing?
    CN3 pin 4,5 and 6. CN3 pin 7

    I have no Idea where they are on the board.
     
  17. JD19

    JD19 New Member

    Joined:
    Nov 18, 2009
    Messages:
    11
    Likes:
    0
    I've identified CN2 and CN3 on the picture. Pin 1 through 7 are from right to left. The Blue wire on CN3 should be 5 Volts when the tv is turned on from standby to ON. The LED on the front should also turn from red to blue if the standby part of the power supply is working. CN3 pins 5,6 and 7 should be 24 volts also. This is how mine works and then the 5 volts should allow 24 volts to go to CN2 (mine doesn't do this part).

    I found out that mine has a bad transformer (I've circled in red). I cann't get the part and have to replace the whole power supply.

    JD
     

    Attached Files:

  18. jomede

    jomede New Member

    Joined:
    Dec 2, 2009
    Messages:
    10
    Likes:
    0
    JD19 thanks for the pic and info. I replaced the power supply with one from discount merchant.com...still does not power on. no power on any of the cn pins. Could the main board be bad?
     
  19. jomede

    jomede New Member

    Joined:
    Dec 2, 2009
    Messages:
    10
    Likes:
    0
    I rechecked the voltages on the top left plug and I have 24 volts on the 3 red wires. No 5 volts on the blue. I also have 24 volts on the connector going to the video board (main) no 5 volts out. This would lead me to believe the main board has a problem. Anyone know the fix? Surface mounted fuse? Any help would be appreciated.
     
  20. jomede

    jomede New Member

    Joined:
    Dec 2, 2009
    Messages:
    10
    Likes:
    0
    Ok..I got a new(Free but used with a known bad ower supply, just had to pay the shipping) control box today. I just swapped out the power supply with the new one I got from Discount Merchant.com. Tv powers on now. Polaroid logo flashes and looks real good. Blue solid screen looks good. When I plug a source in the screen displays the picture in a tye-die looking effect. It doesnt matter which input I use. Haven't tried the HDMI. Could it be the T-conn board? small board on top behind the control box. Not sure as I get a perfect blue screen with noTye-die look. Everything I have read points to the t-conn board. Help !
     
  21. JD19

    JD19 New Member

    Joined:
    Nov 18, 2009
    Messages:
    11
    Likes:
    0
    jomede - It sounds like the problem could be in the A/D board or the input board. Did you check to make sure everything was connected in the new control box correctly? If I remember correctly, all the inputs go directly to the A/D board through pin/socket connection from the input board.

    If your old A/D board is bad (no 5 volts going back to the Power supply) then swapping that back into the new control box would only give you the same problem (will not turn on). you can try that and confirm this.

    If the problem is in the input/output board, you could try swapping from that from old one to the the new one. It is not that hard but you have to just about take the whole control board apart to do it. Let me know if you need help tying this.

    BTW- do you still have your old power supply board. I could use some parts like one of those little yellow transformers! Can we make a deal of some sort?

    Anybody have an old bad power supply I can get for parts for mine?
     

Share This Page