Sanyo DP52449 audio no video

[joeshannallie]

I just have a question and need some advice. I have a Sanyo DP52449 Tv and can get audio but no picture. I have checked the voltages from the power supply board(please see pic) and the 5v is there but the 12 or 15v is not there. The screen is only like a bluish color nothing else. I connected tv cable and was able to get audio. My main question is could power board be some bad and not all the way dead? You know like I could still get audio but no video. I have also replaced the Tconn board. Please reply soon with any advice you may can give.

[dskall]

Re: Sanyo DP52449 audio no video

What is your ps-on voltage in standby

[joeshannallie]

Re: Sanyo DP52449 audio no video

Stand by voltage is 4.

[budm]

Re: Sanyo DP52449 audio no video

Stand by voltage is 4.

Are you sure that your meter is good? 4VDC for STB5V is low.
How about the DCV of that PS_ON/OFF pin when the TV is OFF and when the power switch is activated?
We also need the pictures of the whole board and the whole backside of the TV showing all the boards so we can see how all the boards are connected together.

[joeshannallie]

Re: Sanyo DP52449 audio no video

Thanks Bud for the reply. I assume the meter is good. No reason to think it isnt. I will get more pics a little later today.I was testing voltage by having the set of wires unconnected as you see in the pic and just touching the pins after I pressed the power button. Was that the wrong way? Do I need to check the voltage with everything connected?

[budm]

Re: Sanyo DP52449 audio no video

You need to test the Voltages with every thing connected first because they communicate with each other, read the Basic LCD TV and Monitor troubleshooting guides to get basic idea as how each board interact with each other.

[joeshannallie]

Re: Sanyo DP52449 audio no video

Ok I checked all the voltages with everything connected and tv on. The results are not good I dont think
Small White Connector on Power board=
LDP-1= 010v
LDP-1= 010v
gGND
GND
GND
LCF= 0v
12v= 011v

Small connecter next to main board connector on power board
NC
BL_ADJ=002
BL_ON=002
GND
STB5V=004

Main board connector to power supply
Line/Off=0
15v=0
15v=0
GND
GND
12v=0
12v=0
12v=0
12v=0
GND
GND
D5V=0
PS on/off=0

That is the best I could do. May pick up a new battery for the tester and double check again shortly.
Here is some pics
Also the audio is choppy like with out the cable connected.

[budm]

Re: Sanyo DP52449 audio no video

What Voltage scale are you using? It looks like you are using too high of the Voltage scale that is why it is showing 004V, you should use 20V (19.99V resolution) scale.
But the bottom line is that the main board is not sending the PS-ON ti turn on the rest of the power supplies.

[joeshannallie]

Re: Sanyo DP52449 audio no video

So in your opinion the main board more than likley is bad, Right? Can not find one anywhere. Found a few and they all seem to be missing a connector. Why do you think it has audio but no picture?

[dskall]

Re: Sanyo DP52449 audio no video

Does ps_on change voltage when you push power button?

[budm]

Re: Sanyo DP52449 audio no video

Main board connector to power supply
Line/Off=0
15v=0
15v=0
GND
GND
12v=0
12v=0
12v=0
12v=0
GND
GND
D5V=0
PS on/off=0

That has to be measurement error, no way you can have the backlights on with all the Voltages on the main board connector to be ALL 0V.

https://www.badcaps.net/forum/attach...5&d=1505421797

[joeshannallie]

Re: Sanyo DP52449 audio no video

Will find a different tester today.

[joeshannallie]

Re: Sanyo DP52449 audio no video

Got a different tester today at wally world and the main board connector voltage did not change. Others did.The small connector next to the main board connector on the power board with the new tester now reads
NC
BL_ADJ=2.93
BL_ON=3.29
GND
STB5V=5.03

Main board connector voltage stayed the same on or off

Little connector at the top of the power board changed with new tester
LDP-1= off 0.28 on 11.31
LDP-1 = 0.29 off 11.31 on
GND
GND
GND
LCF=0v
12v= 0.33 off 12.19 on

Tried every way possible to get readings from main board connector and had no luck. So I assume it is the main board but how can I be certain that it is not the power board since I get good audio with cable connected?

[budm]

Re: Sanyo DP52449 audio no video

Where is the PS_ON/OFF?
So now your STB5V=5.03 instead of 4V on the meter with high scale setting.
BL_ADJ=2.93: The main board is sending the Backlight level command as it should

BL_ON=3.29: The main board is sending the Backlights on command as it should, that is why your backlights are on.

12v= 0.33 off 12.19 on: The switched 12V is working and it is being turned on the main board which means the PS-ON command from the main board is preset but you did not list he Voltage from that pin.
Where is the 15V pins reading per your post 7?
Where is D5V per post 7?
So as far as we know now is that the backlights (lights source) are working but you are no seeing the images on the screen.
No image can be due to main board or T-CON board.

[joeshannallie]

Re: Sanyo DP52449 audio no video

There is no voltage at all coming from the power board to main board connector. I will try and probe them a little harder today. I was being gentle with the connector. I thought I probed it fine but I try again today.

[joeshannallie]

Re: Sanyo DP52449 audio no video

New readings after probing a little harder.
Line on/off = 4.97
15v = 15.74
15v = 15.74
GND = 0.00
GND = 0.00
12v = 12.18 on 0.49 off
12v = 12.18 on 0.43 off
12v = 12.18 on 0.40 off
12v = 12.18 on 0.40 off
GND = 0.00
GND = 0.00
D5V = 5.01 on 5.01 off
GND = 0.00
PS on/off = 4.99 on 0.00 off

So what now? I did check the voltage of a big canister that had 400v on it and with power on it only went to 44v. That was on the power board. Can not find a exact main board no where.

[budm]

Re: Sanyo DP52449 audio no video

That looks good, you do have backlights so that is also good. The next thing to check is to find out if the T-con board is getting the 12VDC on both end of the fuse with reference to GND or not.

[joeshannallie]

Re: Sanyo DP52449 audio no video

Could you possibly tell me how to do that?

[budm]

Re: Sanyo DP52449 audio no video

Your TV is going to be easy, see that metal box in the middle between the power supply board? The is the FRC (Frame Rate Conversion board) which get the signals from the main board then it has two output connectors that go down the plastic chassis of the TV to the T-con board on the LCD panel, so the problem can be the FRC board or T-CON board. It can be that the FRC board is not getting the power.
http://www.shopjimmy.com/catalogsear...=Sanyo+DP52449

The connectors on the FRC board has no labels for the pins. We will need to find the service manual for this TV to make it easier to test the Voltages.

[joeshannallie]

Re: Sanyo DP52449 audio no video

I have the service manual. Is that small connector just a extra one on that board? Makes you think there should be wires going to it.