Samsung UN60D6420UFXZC Not turning on

[Wellington1]

Re: Samsung UN60D6420UFXZC Not turning on

I do not know if it would have made a difference waiting a few days but I put a cable into the HDMI 2 slot and had a blu ray playing before plugging in the tv, it did not turn on but the relay clicked and there were what looked like 4 or 5 steady flashes on the power led, just once.

After turning off the player and unplugging the cable I then unplugged the tv and got the same double click and then the two quick flashes six times, repeated twice. I cannot say whether the tv, after being left unplugged for an extended time would have turned on and shown an image with a player on, I might wait a week or two and give it a try.


I would be tempted to simply purchase a Main board but might be throwing money away ( unless one wants a spare just in case ).

[CapLeaker]

Re: Samsung UN60D6420UFXZC Not turning on

well, it sounds like you need a main board.

[Wellington1]

Re: Samsung UN60D6420UFXZC Not turning on

. Is it worth trying to check voltages on or from the Main board just for the sake of knowing? Also, I have read that a power supply can still cause issues under a load, or is the disconnection of the cable between the PS and Main board ( and back light functions ) an indication that it is fine?


Learning can be fun but also a bit of a dilemma! I saw a used Main board for 85.00 from a known working tv or a new one for 132.00, difficult to decide not knowing how much use the tv will give you but then I will not be using it a lot, and I also unplug mine when not in use as I understand there is usually stand by voltage present which has resulted in failures with tvs that were barely used, just time plugged in. Does this generally apply to most sets? I noticed my 50" Panasonic Plasma (manufactured Nov. 2012 ) is cool when off but I unplug it as well. After reading about so many arching problems causing component failure due to the board mounting screws lacking a lock washer I found out that mine had a -2 prefix after the model number indicating it had the updated screws. I was worried it would suffer the same issue - hope this one lasts awhile!

An older 2006 Toshiba Regza 42" lcd had a commonly failed IC on the PS board from excess heat even when plugged in on stand by so I learned from that, although it lasted 8 years before the repair and it still works fine, in fact it has been mentioned I should hold onto it while it still works as they were generally better built back then, I believe this one was still made in Japan.

[Wellington1]

Re: Samsung UN60D6420UFXZC Not turning on

Anyone know which pin locations I can test on the disconnected cable from the PS board at the Main board? Also I came across a test procedure relating to another Samsung ( UN55H6350AF ) Main board and wonder how similar mine is as far as what to check for voltages.

Can this be done with the board on the tv? Very new to this so please bare with me!

[dick_barton]

Re: Samsung UN60D6420UFXZC Not turning on

Can you post the voltages read on the connector from the power supply to the mainboard.
The connect pinout is given on the circuit board. There may be two rows of 12 pins (24 total) but cannot really tell from your photo.

For example
Pin1 Power On/Off 5V
Pin2 Ground 0V
Pin3 Ground 0V
Pin4 BL_On/Off 3.5V
Pin 24 xxxx

[Wellington1]

Re: Samsung UN60D6420UFXZC Not turning on

dick - I did notice some of those numbers but initially was not sure of the pin readout and how they correlate - should I take a close up image of the values printed on the PS board? I assume I can use the metal back panel as a ground source?

[dick_barton]

Re: Samsung UN60D6420UFXZC Not turning on

If you could post some brighter sharp pictures of the power supply they would prove very useful. You can use the metal chassis for ground when measuring at that connector.

[Wellington1]

Re: Samsung UN60D6420UFXZC Not turning on

Upper left area of PS board near the connector to Main:









Hope these help.

[budm]

Re: Samsung UN60D6420UFXZC Not turning on

The exposed pins you can see on the top side of the the board are the ODD number pins, the EVEN number pins you will have to access them from the back side (the wire entrance side) of the connector using skinny probe.

[Wellington1]

Re: Samsung UN60D6420UFXZC Not turning on

One of the connector:







Could one disconnect at the Main board and insert the DMM probe into each corresponding pin hole as shown or does the cable need to be connected at both boards? I see it must send voltage signals both directions.

[dick_barton]

Re: Samsung UN60D6420UFXZC Not turning on

Could one disconnect at the Main board and insert the DMM probe into each corresponding pin hole as shown or does the cable need to be connected at both boards? I see it must send voltage signals both directions.

I think initially it would be best to have the mainboard connected to the power supply so that you can see if any voltages are missing.

Perhaps you could turn the mainboard over and rest it securely off the metal chassis and read the pins from the underside.

[Wellington1]

Re: Samsung UN60D6420UFXZC Not turning on

So grounding of the main board would not be an issue? Just want to be sure! I can have something like a small box to carefully lay the board onto and minimize stress. Do I leave any other cables attached?

[dick_barton]

Re: Samsung UN60D6420UFXZC Not turning on

You may be able to leave all the boards in place if you can insert a small sewing needle into the connector along side where the wire enters the connector. You can tape the needle securely to the tip of your meter probe.

[budwich]

Re: Samsung UN60D6420UFXZC Not turning on

oops was looking at the labelling wrong.

[Wellington1]

Re: Samsung UN60D6420UFXZC Not turning on

After checking the easier to access odd number connections on the PS board at the hard wired connector the readings are:

PIN #
1 OD LEVEL 1.88
3 OD ON 2.21
5 GND 0
7 B13V 12.68
9 B13V 12.68
11 VAMP 17.0
13 VAMP 17.0
15 GND 0
17 B5V 5.35
19 B5V 5.35

As the relay clicked the voltages would drop at most, to be expected I assume as it cycles. As soon as I can find a needle or something similar I will try the even numbered pins.



Using good lighting and a magnifying glass I am quite certain I managed, after going over the even numbered connections at the harness itself three times, pretty sure I made contact, the readings are as follows:

PIN #

# 2 NC 0

# 4 NC 0

# 6 PWM DIM 0

# 8 NC 0

# 10 B13V 12.67

# 12 BLU ON 0

# 14 GND 0

# 16 GND 0

# 18 A5V 5.35

# 20 PS ON 3.28


I was having some difficulty insuring I was actually touching each pin that was under the odd row of wires at the connector and the taped needle was not quite as secure as I would have liked but after multiple tries am certain these are the readings, if anyone feels I need to recheck certain pins let me know, wondering about PS ON value as well as the BLU ON ( back light ).

[Wellington1]

Re: Samsung UN60D6420UFXZC Not turning on

Still wondering about the led power on indicator flashing quickly twice and doing this five times after the tv is unplugged, again each time the relay clicks, which it does twice. I think I noticed the power on led also blink twice when the tv is first plugged in, otherwise it is never lit.

[dick_barton]

Re: Samsung UN60D6420UFXZC Not turning on

Were the backlights on when you did this test since BL_ON and PWM_DIM are both 0V and would indicate no backlights?

OD_Level and OD_On both look very low. I'm not sure what they should be but a search of the forum show other sets to have a working voltage of between 3V to 5V


Can you attach the test procedure document relating to another Samsung ( UN55H6350AF ) you refer to earlier and a clear focused photo of your mainboard to compare it with the document.

[Wellington1]

Re: Samsung UN60D6420UFXZC Not turning on

The back light leds did not turn on, only when the cable between the Main and PS boards was disconnected did they light up, and of course the relay stopped clicking as well.


As the back lights function the problem seems to be pointing towards the Main board, I know one can use some resistors and bridge between 5V Standby and I believe PS ON and BLU ON at the connector on the Main board side which would, if back lights come on, suggest a Main board issue, worth a try or do the voltage readings say the same thing?

I will check the site I was on for any voltage values.

[dick_barton]

Re: Samsung UN60D6420UFXZC Not turning on

It is looking like a mainboard fault.

Any nice sharp photo's of you main board to see if voltage regulators can be identified.

[Wellington1]

Re: Samsung UN60D6420UFXZC Not turning on

The site I used to find a possible cause does not list the voltages at that 20 pin connector. Maybe someone here knows the values for the OD ON as well as OD LEVEL - as I mentioned earlier the fact that the Main boards for these sets sell quite readily and are often not in stock is telling, I still wonder if doing the oven re flow trick might be worth trying just to see.


Here is an image of the main board: