Sony kdl-46hx853 no power

[imran333]

Hi I got Sony 46hx853, no power or standby light , service manual says to check standby voltage on pin no 10 I think on main board, and if voltage is there, then replace main board , standby voltage is present , I have another main board from different tv, but the main board is near enough identical except the audio connectors , I plugged it in and I get standby by light on tv, so the service manual seems correct, but I don't want to replace the main board as it's expensive, the near enough identical main board I got has a damaged connector and all the ic chips etc are identical, so I can use that board to salvage the parts from, the problem I have is no schematic so I'm kind of confused what to check j next , as there's no obvious problems on the main board, like no burnt components , checked some smd caps but no short circuit on them, nothing getting hot, so just need some help and advice, I can solder smd parts and got all the equipment, just need to figure out the problem,
Hope someone can help ?

[nomoresonys]

Re: Sony kdl-46hx853 no power

Try test #3 below, try to do it just as instructed, post results here.

[nomoresonys]

Re: Sony kdl-46hx853 no power

To be clear, the mainboard is the board where you plug your hdmi, cable tv etc. cables into, the powerboard is the one without those type connections.

[budm]

Re: Sony kdl-46hx853 no power

Show us good clear pictures of the whole backside of the TV showing all the boards so we can see what we are dealing with.

[imran333]

Re: Sony kdl-46hx853 no power

Here’s picture of main board , I’ve checked voltages in power supply and they are all present, I got similar board I can salvage parts from, just need help to figure out what part has failed on main board as I don’t have schematic

None of the 4 smd fuses on the main board are blown

[nomoresonys]

Re: Sony kdl-46hx853 no power

Can't follow directions when offered help, I'm out.

[imran333]

Re: Sony kdl-46hx853 no power

Can't follow directions when offered help, I'm out.

I tried the test and all voltages are present and I got another power supply and it made no difference , I’m sorry but I don’t understand what you wanted me to do ?

Yes I never took pictures of the whole back if tv as I don’t have access to it yet but I will do

I’m sorry I’m not ignoring your advice but I got hold of a power supply and it made no difference and all voltages are present once you plug it in and I checked voltages when pressing power button and voltages are all present and exactly same as the voltages written on the board, Ive narrowed it down to the main board and only a hour ago I tested with another power supply but exact same problem

[imran333]

Re: Sony kdl-46hx853 no power

Can't follow directions when offered help, I'm out.

Hope you can still help as everyone makes mistakes

[nomoresonys]

Re: Sony kdl-46hx853 no power

Some mainboard and powerboard testing there: https://www.youtube.com/watch?v=ocqnqmBxiqY

[nomoresonys]

Re: Sony kdl-46hx853 no power

Mainboards can look similar but be very different, need to mach the alphanumeric string on the white stickers.

[imran333]

Re: Sony kdl-46hx853 no power

Mainboards can look similar but be very different, need to mach the alphanumeric string on the white stickers.

I understand the main board I showed you is the main board from my tv but the main board I got which is similar I just want it to salvage the parts from as all the smd components are the same with the same smd part numbers , only difference is the audio connector, I'll check that video you sent and report back

[nomoresonys]

Re: Sony kdl-46hx853 no power

need close up picture of the map/legend describing the pins of connector on powerboard or just write them out with pin description like ground etc. and pin number for each pin.

[nomoresonys]

Re: Sony kdl-46hx853 no power

Another little test, unplug the wifi module if equipped and see if anything changes.

[imran333]

Re: Sony kdl-46hx853 no power

need close up picture of the map/legend describing the pins of connector on powerboard or just write them out with pin description like ground etc. and pin number for each pin.

I'll do that next but I'm presuming the power board is fine as I tried another known good working one which I borrowed from a friend but he doesn't have another main board for me to try , but everything is telling me it's the main board but I will take close up pictures of the connectors and voltages ,

There's no regulators on the main board like in the video you told me to watch but here's close up pictures of the main board , I was thinking maybe it's a fault with a dc converter as there's no standby light but I got no schematic

[nomoresonys]

Re: Sony kdl-46hx853 no power

It's a process of elimination, the backlights and powerboard can be tested if they pass the test you move on to the rest. It's how most of us test tvs, can't help without the requested pictures or info.

[imran333]

Re: Sony kdl-46hx853 no power

It's a process of elimination, the backlights and powerboard can be tested if they pass the test you move on to the rest. It's how most of us test tvs, can't help without the requested pictures or info.

When I plugged in the other main board I got , the standby light comes on so I'm presuming it's the main board that's faulty as with the original main board no standby light, I got backlight tester and I just need to figure out what the voltages should be in the first place, I got the pictures but if the main board was not faulty then I would have got blink code as it's a Sony and service manual says if there's standby voltage on pin 10 on main board which there is, it says it's the main board that's faulty so everything is telling me it's the main board

[imran333]

Re: Sony kdl-46hx853 no power

It's a process of elimination, the backlights and powerboard can be tested if they pass the test you move on to the rest. It's how most of us test tvs, can't help without the requested pictures or info.

I've ruled out the power supply board as I tried another one and all voltages are correct , the backlights I really don't think so bcuz all the voltages was even on every set of wires I tried

[nomoresonys]

Re: Sony kdl-46hx853 no power

What is the voltage of the BL-ON pin with tv in standby, and when you turn tv on??

[nomoresonys]

Re: Sony kdl-46hx853 no power

What exactly does the tv do, do you get backlights or a flash of backlights??

[imran333]

Re: Sony kdl-46hx853 no power

What exactly does the tv do, do you get backlights or a flash of backlights??

Tomorrow I’ll check backlight on voltage as I forgot but the tv does nothing at all but all I hear is relay click on when plugged in then nothing at all, but when I unplug the cord then I’ll hear relay click off, in the past on another faulty Sony tv where the power supply was faulty , the relay would click on when plugged in and click off straight away, but on this one it will click on when plugged in then nothing until I unplug the cord.

So I’m thinking when it’s plugged in, the power supply is on the whole time but maybe main board is faulty so the main board is not sending the signal to turn backlights on and not able to give standby light or blink code as the main board is faulty bcuz when the similar main board is plugged in I got standby light but I never press power button in case the similar board blows something else