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Ask Shahid Your Own Question
Shahid
Shahid, Technician
Category: TV
Satisfied Customers: 10640
Experience:  I have been repairing electronic gear since 1993 as a qualified Sony tech
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I have a song kdl46z4500 and no power

Customer Question

I have a song kdl46z4500 and no power
Submitted: 1 month ago.
Category: TV
Expert:  Aric replied 1 month ago.

Hello, My name is ***** ***** I'll be assisting you. I'm sorry you're having problems. I'm reviewing your details now and will reply shortly.

Expert:  Aric replied 1 month ago.

The 250V is the AC Input- the board will always have that present unless the mains fuse is dead. it's the DC outputs on the board that are more important to check offhand. That said, are you saying you installed a new power supply board, and still have no standby light?

Customer: replied 1 month ago.
Correct
Expert:  Aric replied 1 month ago.

Okay this means you have a bad Mainboard- and the power board is find. The mainboard produces the standby light and allows the power supply board to engage with a turn on command once the power button is pressed. The mainboard is the one with the AV jacks located on it and is the central processor for the TV. So you would need to replace the Mainboard for these symptoms.

Customer: replied 1 month ago.
I would rather message
Customer: replied 1 month ago.
I have a spare so I will try it now
Expert:  Aric replied 1 month ago.

I am not sending that phone call offer- you can ignore it.

Expert:  Aric replied 1 month ago.

You have a spare mainboard?

Expert:  Aric replied 1 month ago.

Let me know if you need further assistance. Also, before you go, could you please click a POSITIVE RATING (by scrolling all of the way to the top of the page, and clicking 3-5 stars), so that I am credited for working with you today?

Customer: replied 1 month ago.
New signal board in no change
Expert:  Shahid replied 1 month ago.

Hello, I'm Shahid. Sorry to hear that you're having trouble with this but I'll do my best to help.

Customer: replied 1 month ago.
Hi I have fitted new power and main/signal boards but the same issue persists
Expert:  Shahid replied 1 month ago.

OK, I'm working on it, give me 5 minutes please.

Customer: replied 1 month ago.
Thanks
Expert:  Shahid replied 1 month ago.

Please find CN6150 or CN6156 connector on power supply board and check Standby 3.3V DC at pin-7 of that connector while TV power cord is plugged in.

What readings appear on meter?

Customer: replied 1 month ago.
Pin 7 from the top or bottom of the strip connection
Expert:  Shahid replied 1 month ago.

Pin-1 would be marked with little arrow or number or STB3.3V would be stamped near pin-7

Customer: replied 1 month ago.
STb but no voltage marked on the board
Expert:  Shahid replied 1 month ago.

No problem, meter should show 3.3V DC reading, do you get that?

Customer: replied 1 month ago.
2.8v
Expert:  Shahid replied 1 month ago.

It should be exactly 3.3V DC.

Is the meter being used tested and working?

Expert:  Shahid replied 1 month ago.

Another way is to disconnect harness plugged in that connector and test STB volts again, without load.

Do you still get 2.8V?

Customer: replied 1 month ago.
Now I'm not even getting that
Expert:  Shahid replied 1 month ago.

Please touch the meter black lead to GND point of power supply board and use red lead to measure STB volts at pin-7 while TV power cord is plugged in working power outlet.

If power board is OK then you should get 3.3V DC reading.

Customer: replied 1 month ago.
2.8v this is a brand new board today
Expert:  Shahid replied 1 month ago.

I understand and trying to troubleshoot the problem. You should have 3.3V reading no matter if board is old or new.

3.3V standby volts is must to wake up the main controller chip on main board to get standby light On and main power section will turn On when you press power button on TV or its remote.

2.8V is insufficient for main controller chip that is why you don't get any response from TV.

Do you have old power supply board and can install it in TV?

Also, confirm your multimeter to make sure it is showing correct readings, test a battery volts that should be 1.2V DC reading.

Customer: replied 1 month ago.
Is there any other way to test the board. The chances of a brand new one being faulty must be remote
Expert:  Shahid replied 1 month ago.

Let me explain, standby section works as soon as you plug TV power cord in so you will get standby 3.3V output instantly that goes to main board to wake it up and it will send Power On command to power board to switch On main power section so the other boards and sections get required volts and you get picture and sound on TV.

Now even if you disconnect power supply board from main board of TV and plug power cord in, standby volts must be available. If it doesn't happen the power board is faulty either it is new or old.

I hope these info will help to confirm the power supply board.

Have you tried old power board in TV as requested in previous reply?

Customer: replied 1 month ago.
Can we reconvene in the morning, I am about out of patience with this right now.I believe the meter is fine as I get 251v at the end of the cable and on the board
Expert:  Shahid replied 1 month ago.

No problem, we can continue it at later time.

Please take out a battery cell from a remote and test DC volt of it to confirm the meter.

250V are AC volts which is main power supply coming to house and we are testing DC volts of standby with meter so meter should be set on DC Volt range to check 3.3V

Customer: replied 1 month ago.
I will try the old board again in the morning but I didn't get 3.3 v off it that's why I ordered a new one.
Expert:  Shahid replied 1 month ago.

OK, we will discuss it by tomorrow, please message me here when available and give me little time to respond as I might be offline at that time.

Thanks.

Customer: replied 1 month ago.
Just put the original board in and 0v
I will sleep on it
Expert:  Shahid replied 1 month ago.

Sorry to hear that, your new power board is defective, please return it and ask for another power board that should give 3.3V STB reading.

Thanks.

Customer: replied 1 month ago.
Just off to get new battery's for my tester before I contact the supplier as it was sent from Europe so not cheap or quick to return so I must be sure that the board is defective.
Expert:  Shahid replied 1 month ago.

OK, we need to verify voltmeter first then confirm the standby 3.3V output to make any decision.

Expert:  Shahid replied 1 month ago.

Do you need any further assistance with this question?

Customer: replied 1 month ago.
Hi, waiting for board to arrive from USA should be Tuesday
Expert:  Shahid replied 1 month ago.

No problem, please make sure you're getting identical board as replacement.

Thanks.