Sanyo DP42D23 No picture, has sound, flashlight shows menu

[phan1978]

Hello,
I am an amature, self taught TV repair guy (only fixed a few tvs and those were just diagnosing the bad boards and replacing them). I don't know much lingo but I can understand easily. So, this tv has power, sound, but what seems to be a blank screen (no picture). I shined a flashlight on the screen and can see the menu screen faintly. I attached some pics of the boards if that may help. So, it seems as if the power board is fine. I check all the capacitors on all the boards and they seem fine. I think it is either the main board or the little green board at the middle-bottom (possibly called the Control Merger). Any help would be amazing! Thanks

[dskall]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

In a dark room do you get a flash when first powered on?

[phan1978]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

In a dark room do you get a flash when first powered on?

Just tried it. The screen stays full black. Zero signs of a screen flash or anything. The green power light indicator comes on, as it always does.

[dskall]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

At connector K702 Need voltages Will need pin#- PIN DESCRIPTION -Pin voltage in standby-Pin voltage when pushing power button.
Format:
Pin# - Pin Description - Pin Voltage standby - Pin voltage power on
1 - XXXXXXX - XXv - XXXv
2 - XXXXXXX - XXXv - XXXv
3 - XXXXXXX - XXXv - XXXv
4 - etc.

[phan1978]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

1. PS-on - 0.03v - 3.20v
2. GND
3. 5VSTB - 5.05v - 5.04v
4. 5VSTB - 5.05v - 5.04v
5. GND
6. 12VA - 0v - 12.24v
7. 12VA - 0v - 12.24v
8. GND
9. 12VA - 0v - 12.24v
10. GND
11. LINEOFF - 0v - 0.50v
12. BL-DM - 0v - 1.17v
13. BL-ON - 0v - 3.16v
14. 12VA - 0v - 12.24v

[dskall]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

On your K701 four wire connector check voltages at led1+ and led1- led2+ led2- with power on. Then power off unplug connector do same check with each one push power button record max voltage from each as you power tv on. Here's video might help https://www.youtube.com/watch?v=EgRKJAqYqeo

[phan1978]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

sweet youtube video! When powered on and clip is in, I get nada when using the black and red on the MM to touch the - & + LED points. When i ground the black to the metal and touching the points with the red, I get 0 on everything except pin7. On pin7, I get 250v with that method.

[dskall]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

Sorry misread from your other picture. Just learning this. Do you get anything across each black and white wire? I'm a bit confused about the board markings.

[phan1978]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

Sorry misread from your other picture. Just learning this. Do you get anything across each black and white wire? I'm a bit confused about the board markings.

it seems as if Pin1 & 7 are the -&+for one set of LEDs. Pin 2 & 6 are empty. Pin 3 & 5 are the other -&+'s for the second set of LEDs. Pin 4 may be a ground but is not a factor in this.

so tv power is ON - when I touch the Red MM(multi-meter) to pin7 and the black MM to pin 1, I get nothing. When I touch the Red MM to pin5 and the black MM to pin 3, I also get nothing. The only time I get a reading other than zero is when I ground the black MM to the metal panel and touch pin7 with the red MM. Then, I get anywhere from 239-252v.

[dskall]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

Can you post panel sticker number. Upper right hand corner?

[phan1978]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

Can you post panel sticker number. Upper right hand corner?

Posting the panel sticker picture and a picture of the LED clip when in.

**Not sure why pics are oriented sideways

[dick_barton]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

From what I can see on the data sheet CN701 connector
Pin1 - Pin3 = 68V
Pin 5 - Pin7 = 102V

Data sheet attached

[phan1978]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

From what I can see on the data sheet CN701 connector
Pin1 - Pin3 = 68V
Pin 5 - Pin7 = 102V

Data sheet attached

I have tried those pin combos and nothing. Only pin7 gets voltage when grounding the black
So, it is looking like it IS the power board, right?

[dskall]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

If you are getting nothing between pin1 and 3 I would say it is power board. See what Dick has to say. He took my line (Willing to help but I'm no expert)

[dick_barton]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

So you put your multimeter probes between pins 1 & 3, and also 5 & 7 and no dc voltage.
Also with the black meter lead on chassis the only voltage you have on any of the pins is on Pin 7.
Is that all correct.

Unplug the led connector and repeat the above and see if you have any voltages on any of the pins.

Edit
Out of curiosity are pins 3 & 5 connected together when you check them using your meter on the ohms range.
If they are then:-
the two led strings would appear to be wired in series requiring 168V at pin 7.
So if you are reading 250V then it would appear that you have an open circuit led(s) problem. But again this would only be if the two led strings are wired in series.

[phan1978]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

So you put your multimeter probes between pins 1 & 3, and also 5 & 7 and no dc voltage.
Also with the black meter lead on chassis the only voltage you have on any of the pins is on Pin 7.

Is that all correct. YES

Unplug the led connector and repeat the above and see if you have any voltages on any of the pins.

I tested it both plugged and unplugged and the numbers were the same

[dskall]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

I think they are in series. I looked at back of board from shopjimmy and appears to be the case though the pdf shows different.

[Icitte]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

noob suggestion/question but, if only ONE LED is defect like burned or bad solder is the whole thing dosnt work?

[dskall]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

All your board voltages look good and if you get the voltage to your backlights which now I think you are. That leaves the backlights as the problem and depending on whether they short or open just one can cause shut down.

[dick_barton]

Re: Sanyo DP42D23 No picture, has sound, flashlight shows menu

I believe that you have an open circuit led. Only one is needed to stop the led lighting or even flashing briefly at switch on.
Time to open up the panel carefully and remember the order in which you remove the panel and diffuser sheets.

There is plenty of advice on threads here for testing leds or search for Youtube videos.