sanyo no back ligth

[MisterD]

Re: sanyo no back ligth

what about the wire that he want fromstb5v on cn2 to stb5v oncn6?

You already have this done.... connect the resistor between PIN1 (5vstby) and pin3 (BL_ON) of CN6. So leave the resistor in place. Now just cut the one wire into like I said above, this way it is no longer connected to the mainboard, then follow the steps I said by turning on the TV and see if you have backlights.

I don't think you have to do anything with CN2, he's just saying you have 2 different 5VSTBY Sources.

[MisterD]

Re: sanyo no back ligth

Here it is again
He is saying plug connector CN6 back in and to just cut the one BL_ON wire into that's on CN6, leave it at least 3 inches long at the end going to that connector (CN6) so you will be able to splice it back together later, Leave the resistor where it is and turn on the TV and see if you now have backlights.

[ealequi]

Re: sanyo no back ligth

same thing. Get audio,video but not lit-up

[MisterD]

Re: sanyo no back ligth

With the TV turned on check the voltage now at BL_ON on connector CN6 and see what it is.

[budm]

Re: sanyo no back ligth

You will put the cn6 connector back in place, but cut the BL_ON wire, leave it long enough so you van splice the wire back together once we fix the problem, that is how I troubleshoot misterd philips TV.

[ealequi]

Re: sanyo no back ligth

3.7v

[MisterD]

Re: sanyo no back ligth

3.7v

Okay, did you cut the BL_ON Wire on CN6 ?

[ealequi]

Re: sanyo no back ligth

yes

[MisterD]

Re: sanyo no back ligth

Bud, he has 3.7V at BL_ON with the 1K resistor in place and he has the wire cut now.

[budm]

Re: sanyo no back ligth

OK, so now you do get the LED to be on, but still no backlights?

[ealequi]

Re: sanyo no back ligth

There is a misunderstanding. Is the back ligth went you able to see the video but is dark? That is what i have. I need the brite ligth wish i imagine that is the led. The tv still doing the same thing that make me come to the forum

[MisterD]

Re: sanyo no back ligth

The backlight (a white light ) can be seen through the holes in the metal chassis from behind with the back off the TV, the LED he is referring to is the little light on the front of the tv plastic case. Do you have that white light?

This is from your first posting and it sounds like the backlight is not working because you are using the flashlight method to see video.

"I have a sanyo dp42647 when i turn it on there is a black screen with sound. If i put a flashligth close to the screen i can see the video. Any idea?"

[ealequi]

Re: sanyo no back ligth

ok. i missing the backligth. i have video, sound led i green but no backligth.

[budm]

Re: sanyo no back ligth

Well at this point we have verify that the backlights are not working not due to the main board problem but due to your bad power supply/inverter combo board problem or due to bad lamps.
We do not have the diagram to troubleshoot down to component level, but I want to make sure that you DID NOT EVEN SEE THE SCREEN FLASH for seconds? The problem is now down to either bad board or bad lamps, with one or two bad lamps I will expect to see the screen lights up for seconds then shutdown if the inverter board is OK, but if the inverter board is bad it may not even try to light up the screen at all, this is where you have to make the decision if you will want to try ordering the new power supply-inverter board to find out if it will fix the problem or not.

[MisterD]

Re: sanyo no back ligth

deleted.

[MisterD]

Re: sanyo no back ligth

Before he added the resistor his readings were:
bl_on = 1.3
bl_dim = 3.2
5vstb = 5.v
Before making any changes BL_ON was only 1.3V, then after adding the resistor BL_ON was 3.7V and still no backlights. If there is a problem with the inverter board or bulbs why would it be at 1.3V. since the 1.3V would still be there and he is adding 5V through the 1K resistor I would think it would be higher than 3.7V, is it possible there is a shorted component on the inverter section or bad lamps pulling that voltage down?

[budm]

Re: sanyo no back ligth

That 1.3V can be the main board is not pulling high enough, there is voltage divider resistoirs that the 1K is feeding, that is why it will never be at 5V, 3.7V is more than enough to drive the transistor. That 1.3v reading was generated by the main board, since we cut that line open, all he now is the 5V feeding through the 1K resistor.
See post 86 for typical receiving circuit.
If he trace that BL_ON line, there will be a resistor connected to that pin.
Without the diagram of of the board, we cannot check for test points.

[MisterD]

Re: sanyo no back ligth

I see a lot of variances of this power supply board for your model, if you do order one BE VERY CAREFUL to get the part number off of the white bar code sticker and not the pc board itself, I see some on ebay and also some places on ebay repairing your board if you send it in. you can also check shopjimmy.com to see what they have.

[lorins_core]

Re: sanyo no back ligth

Ok i Suggest. Would you try to Resolder. fist the Main Power Supply?. then Try if have no Luck. Try The secondary. they have a Old Solder lead at the Main Board. I Suggest Only. Good Luck Friend.

[budm]

Re: sanyo no back ligth

OK. please check the fusible resistor R322 that feed the B+ to the inverter transformer driving circuit.