Samsung LE32M87BD - stuck in standby - blinking LED

[noledud]

Hi all

This is my first attempt at an LCD repair

When plugged in the LED blinks 5 times then trys to power up the screen

Back light comes on for a second then goes off and the LED starts blinking again

If i leave it plugged in for 5 min then the back light will power up but nothing responds on the TV except off on the remote or button then the cycle starts again

attached are photos

can you advise me on where to start as i said this is my first LCD tv as i have only worked on plasma's

[smai]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

disconnect the the inverter board , turn it on, same cycling or different result ?

[tom66]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

Is it me or is one of those capacitors on the power supply slightly bulging?

[noledud]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

Samai - when the power is removed from the inverter board i get 6 flashes then off for a min then 6 flashes again, no more back light coming on

tom66 - must be the pic iv triple checked and all look ok

[noledud]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

there was a screw missing from the PS so some one has been inside here also on the back of the PS there is some stickers, they are not ment to be there so the PS has been replaced at some point it looks like

[tom66]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

Check voltages on PSU outputs. Are they labelled?

[noledud]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

yeah they are but i have no way to stick my DMM in when the plug is connected - sorry if im being thick

[noledud]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

have i got to bridge 2 pins to turn the ps on so i can check voltages at the plug ?

[tom66]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

You can just press your probe into the point where the sheath meets the pin.
Is there a BN44-####### part number printed on the PSU somewhere? (# = any digit)

[noledud]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

bn44-00156B - im not sure what you mean, if i push from the top i get no readings as its not touching the metal - if i take the plug out i can then reach all the pins to measure.

[noledud]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

here is a pic of the connector plugged in my probe wont fit any where

[anotherdude]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

here is a pic of the connector plugged in my probe wont fit any where

your probe will go into the connector pins, where the wires are

[noledud]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

me being thick im getting readings from the mainboard end not the PS end - i will post all in 1 min

[tom66]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

I do literally just press the probe into where the wire meets the connector, with it installed. With light pressure your probe will touch the metal sheath around the pin which is usually less than a mm in. You can also use the metal chassis as ground.

I don't have a schematic for this PSU unfortunately, but I found this service manual:

Page 132 - pin outs.

"B" volts - active when not in standby
"A" volts - always active
Main_PWR_CTRL - on/off signal to PSU

[selldoor]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

If your probe pins are too fat , a lot of people have used a sewing needle inserted into each
socket hole and take the reading off the needle

[noledud]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

brill thanks

ok here they are as you look at connector
0.01 - 0.01
12.05 - 12.05
0.00 - 12.05
0.00 - 0.00
5.40 - 5.40
5.40 - 5.40
0.00 - 0.00
0.00 - 0.00
11.99 - 11.99
0.00 - 0.00
0.00 - 5.22
0.00 - 3.41

[noledud]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

23. 0.01 - 0.01
21.12.05 - 12.05
19. 0.00 - 12.05
17 0.00 - 0.00
15. 5.40 - 5.40
13. 5.40 - 5.40
11. 0.00 - 0.00
9. 0.00 - 0.00
7. 11.99 - 11.99
5. 0.00 - 0.00
3. 0.00 - 5.22
1. 0.00 - 3.41

[tom66]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

Are those 12.05V lines testing at 12V or 13V? Just to check, they are marked 13V on pin out.

[noledud]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

12v

[noledud]

Re: Samsung LE32M87BD - stuck in standby - blinking LED

when the back light fires up for a split second they then drop to nearly 0 but the back light goes off just before and they go back up