Samsung LE37A556P1F Flashing red light

[budm]

Re: Samsung LE37A556P1F Flashing red light

It does not sound like you order the correct PCB assembly for this model!
By the way, I keep getting confuse between your original post and your pictures with the TECHAMP posting on your original post, I wish he will post on the new post instead so I can answering to the right person since they are not the same model, as you can see his main board picture does not have or use that small connector like your new board, but your old board uses/needs that small connector.

[Jasgriff]

Re: Samsung LE37A556P1F Flashing red light

I actually ordered a second mainboard for this set which turned out to be a slightly different model.

It doesnt have the connector or the resistor attached which allows me to test if that pin connects to the collector through the resitor and it definitely does.

[Jasgriff]

Re: Samsung LE37A556P1F Flashing red light

Can you please post the picture without the marking so I can see if the trace is connected to the Collector pin ( middle pin the small 3-pin device) through the resistor?
Thanks

Sure....

[budm]

Re: Samsung LE37A556P1F Flashing red light

Can you please post the picture without the marking so I can see if the trace is connected to the Collector pin ( middle pin the small 3-pin device) through the resistor?
Thanks

[Jasgriff]

Re: Samsung LE37A556P1F Flashing red light

I have traced BLU back to the mainboard and here is a pic of what it look like and how I tested it.

GND to BLU = 0.1v
GND to Point 1 = 0.1v
GND to Point 2 = 5.2v
GND to Point 3 = 5.2v

[budm]

Re: Samsung LE37A556P1F Flashing red light

While testing connector 1 with connector 2 and 3 plugged into the mainboard I get the following...

Adim = 0v
BL = 0.1v

"This is in the on state where if connector 1 was hooked up it would give me a completely blank picture.

With connector 1 and 3 connected I tested connector 2 on the mainboard.

BLU = 0.1v
Admin = 0v
PWM = 3.2v

Ta for the help with the pins this will help when I am do a little more testing tonight."

Well per your voltage measurement, you do not have the BL_ON feeding the power supply board which is fed into Connector2 by the main board, and this signal flows into connector 2 right through to connector 1 BL_ON pin which is then sent it out to the inverter board. You should be able to trace out this BL wire from power supply board back the main board connector.

[Jasgriff]

Re: Samsung LE37A556P1F Flashing red light

Forgot to bring home my camera!

Thought I would list the pins on Connector 3.

1 P8
2 N/C
3 S8
4 GND
5 GND
6 GND
7 12.5v
8 12.5v
9 GND
10 GND
11 GND
12 GND
13 5.3v
14 5.3v
15 5.3v
16 5.3v
17 GND
18 GND
19 12v
20 GND
21 12v
22 12v
23 N/C
24 N/C

Whats the best way of testing these pins? I have tried to do it on the power board with the cable not connected to the mainboard but i cannot read anything. I assume that the power board knows that the cable is not connected?

With only Connector 3 connected the mainboard is getting power as I can measure voltage across some of the Ic's I will write my finding down shortly.

[retiredcaps]

Re: Samsung LE37M86BD wont turn the screen!

2) Circled in red are some ICs. What is the part number?
P2804ND5G, N- & P-Channel Trans.

1) Here is the datasheet for

http://pdf1.alldatasheet.com/datashe...P2804ND5G.html

Refer to the diagram for pinouts.

2) Measure the resistance between S1-G1, S1-D1, D1-G1, S2-G2, S2-D2, D2-G2 for all chips. You can do this in circuit and report all readings. Any reading under 30 ohms suggest the mosfet might be shorted and warrants desoldering and verifying the reading out of circuit.

3) PS. Since you are getting sound, the power LED on, and a brief flash of backlight, this narrows down the problem to the inverter board.

[TechAMP]

Re: Samsung LE37A556P1F Flashing red light

My response is to Jasgriff. Why has TechAMP ambushed Jasgriffs thread, lol.

Sorry. I'm new at this forum. Couldn't fix the problems with the "Making new post, Editing / deleting" wrong messages. I'll try to make a new thread next tim.
Thank U for your patience.

[TechAMP]

Re: Samsung LE37M86BD wont turn the screen!

Hookup a DVD source playing a movie. Plug it into the TV. In dark room, ..

1) ..can you see the DVD playing without the backlight on? nothing
Try shining a flashlight on it. didn't help.. Is there sound? Yes

2) Circled in red are some ICs. What is the part number?
P2804ND5G, N- & P-Channel Trans.

3) circled in yellow are SMD fuses. 3A/32V, all are OK
Is it a good idea if I disconnect all inverter channels by disoldering those 3A fuses, and test only one ch. at a time?

On PSU board, there is no pulses at " PMW & ADIM". Is that normal. There are no pulses at all on the Inverter board, when the TV is ON!

I made & noted down som measurements on the boards for your info!

[py3m4n]

Re: Samsung LE37A556P1F Flashing red light

I have had a snoop about and it doesn't look like the eeprom is a problem on that series, from what I can glean the eeprom is capable of automatically resetting itself. Looks likes it's only a problem on previous years units.

[Jasgriff]

Re: Samsung LE37A556P1F Flashing red light

Connector 1 these signals go to the Inverter board
The ADIM, BL signals are passed through from Connector 2 which connected to the main board.
NC - N/A
ADIM? - Untested: Backlights dimming voltage (0=min, 5v = max brightness)
BL - Untested: Backlights on
NC - N/A
GND - Tested OK
GND - Tested OK
GND - Tested OK
GND - Tested OK
GND - Tested OK
24V - Tested OK
24V - Tested OK
24V - Tested OK
24V - Tested OK
24V - Tested OK

Connector 2 Left to right

BLU - Untested: Backlights ON signal from the main board (3.3~5v = ON)
Adim - Untested: This pin gets the 0~5vdc Dimming control signal from Main board
PWM - Untested: This pin is not used, it is the Pulse Width Modulation signal (another method of Dimming the backlights) from the main board for Dimming control, is not used on this set.
GND - Tested OK
+5v - Tested OK: 5Vdc to the main board

So you need to have the BL 3.3~5VDC on this pin for the Inverter to come on, you already have the 24vdc, you just do not have the ON signal per your post.

While testing connector 1 with connector 2 and 3 plugged into the mainboard I get the following...

Adim = 0v
BL = 0.1v

This is in the on state where if connector 1 was hooked up it would give me a completely blank picture.

With connector 1 and 3 connected I tested connector 2 on the mainboard.

BLU = 0.1v
Admin = 0v
PWM = 3.2v

Ta for the help with the pins this will help when I am do a little more testing tonight.

[Jasgriff]

Re: Samsung LE37A556P1F Flashing red light

We prefer the actual readings. I have no idea of your background and/or level of knowledge so "OK" means nothing.

If you wrote instead

24V - measured 24.01V

then, I would agree the voltage is OK.

PS. We want pictures of your board, not some stock photo. A stock photo does not show hot spots, glue turned conductive, burnt resistors, etc.

Sorry,

24V - 24.3v
24V - 24.3v
24V - 24.3v
24V - 24.3v
24V - 24.3v

I will sort out some better pictures when I return home from work. I used those stock photos just to see if there was anything thing that could be tested whilst I had the day off twiddling my thumbs

Cheers for your help.

[Jasgriff]

Re: Samsung LE37A556P1F Flashing red light

My response is to Jasgriff. Why has TechAMP ambushed Jasgriffs thread, lol.

Sounds like you might have a corrupted eeprom on the mainboard. Was it caps on the power supply that you replaced? I know with the LE40R88BD series that this is quite common (seen it myself) where after replacing the capacitors on the power supply the eeprom is corrupted on the mainboard the first time you boot the T.V. All that said, I am not sure if this will apply to your model but it can't do any harm to look into it.

Hi Py3m4n,

I changed all of the capacitors on the cold side of the board and it came on a couple of times for a few seconds then straight off sometimes you could hear a high pitched noise or scream coming from the mainboard by the sound of it.

When I get back from work I will start to check the mainboard I will also take some good pics of it so that you can point me in the right direction of what to check.

Ta for your help.

[budm]

Re: Samsung LE37A556P1F Flashing red light

Connector 1 these signals go to the Inverter board
The ADIM, BL signals are passed through from Connector 2 which connected to the main board.
NC - N/A
ADIM? - Untested: Backlights dimming voltage (0=min, 5v = max brightness)
BL - Untested: Backlights on
NC - N/A
GND - Tested OK
GND - Tested OK
GND - Tested OK
GND - Tested OK
GND - Tested OK
24V - Tested OK
24V - Tested OK
24V - Tested OK
24V - Tested OK
24V - Tested OK

Connector 2 Left to right

BLU - Untested: Backlights ON signal from the main board (3.3~5v = ON)
Adim - Untested: This pin gets the 0~5vdc Dimming control signal from Main board
PWM - Untested: This pin is not used, it is the Pulse Width Modulation signal (another method of Dimming the backlights) from the main board for Dimming control, is not used on this set.
GND - Tested OK
+5v - Tested OK: 5Vdc to the main board

So you need to have the BL 3.3~5VDC on this pin for the Inverter to come on, you already have the 24vdc, you just do not have the ON signal per your post.

[retiredcaps]

Re: Samsung LE37A556P1F Flashing red light

24V - Tested OK
24V - Tested OK
24V - Tested OK
24V - Tested OK
24V - Tested OK

We prefer the actual readings. I have no idea of your background and/or level of knowledge so "OK" means nothing.

If you wrote instead

24V - measured 24.01V

then, I would agree the voltage is OK.

PS. We want pictures of your board, not some stock photo. A stock photo does not show hot spots, glue turned conductive, burnt resistors, etc.

[retiredcaps]

Re: Samsung LE37A556P1F Flashing red light

There comes a glimpse of the backlight for a few milliseconds and then disappears.

1) Hookup a DVD source playing a movie. Plug it into the TV. In dark room, can you see the DVD playing without the backlight on? Try shining a flashlight on it. Is there sound?

2) Circled in red are some ICs. What is the part number?

3) The pics are good, but resolution is a bit small on the inverter board. I circled what I think are SMD fuses. A fuse should be marked as something like F100 on the pcb.

A single blown fuse could be causing the backlight not to come on. Check them with your multimeter. A good fuse should measure less than 1.0 ohms.

[py3m4n]

Re: Samsung LE37A556P1F Flashing red light

My response is to Jasgriff. Why has TechAMP ambushed Jasgriffs thread, lol.

Sounds like you might have a corrupted eeprom on the mainboard. Was it caps on the power supply that you replaced? I know with the LE40R88BD series that this is quite common (seen it myself) where after replacing the capacitors on the power supply the eeprom is corrupted on the mainboard the first time you boot the T.V. All that said, I am not sure if this will apply to your model but it can't do any harm to look into it.

[Jasgriff]

Re: Samsung LE37A556P1F Flashing red light

Do you have sound when the TV is turned on?

Have you got all the inverter power cables properly secured; including the cable that is sometimes present going from T-con to power supply?

No sound through any combination of cables that I have tried.

Just tried taking the connectors off and reconnecting them nice and secure but there is still no sound.

[tom66]

Re: Samsung LE37A556P1F Flashing red light

Do you have sound when the TV is turned on?

Have you got all the inverter power cables properly secured; including the cable that is sometimes present going from T-con to power supply?