Sanyo dp50741 main board j4je

[ricosavy]

I have a 50" sanyo plasma tv it will not power on.i have 5 volts standby also when i plug the tv on i can hear relay click and i see my power on voltage go hi to try turn tv on but it does not power on shuts off. I never see led power on i know they sell a kit for main board to repair power on issue.does any one know what this kit contains.any help is appreciated.

[ricosavy]

Re: Sanyo dp50741 main board j4je

The power led will not come on not even for a second.i disconnected this part in picture below.and now the green led will come on and then it turns off.i can push the power button and it will try to turn on then it turns off again. Before no response and no led light up.does this mean this part is bad.

[Caleb]

Re: Sanyo dp50741 main board j4je

Attaching the service manual, it has trouble shooting flow chart starting on page 33

[ricosavy]

Re: Sanyo dp50741 main board j4je

I took a ohms reading of the amp chip for sound ohm out way to high meaning it is bad.i was wondering if i took out the diode that is power fail one for the 13v to see if it would turn on.Would it cause something else to burn or just turn on with no sound.

[ricosavy]

Re: Sanyo dp50741 main board j4je

Lv4906v is bad chip the power fail diode is d1668 audio power 12v b0acdj000007 is part number for diode

[ricosavy]

Re: Sanyo dp50741 main board j4je

I checked all the power fail diodes the only one that i see is not in spec is the one for d1668 it reads about 2.5 volts.when it should read 12 volts any ideas where i need to start testing to see why it is low.also i get no power led light it will no respond when i hit power button.only time it responds is when i discount cable from power supply to logic board then i can hit power and green light will turn on after about 10 seconds it will shut off

[tw2005]

Re: Sanyo dp50741 main board j4je

have you seen the norcal715 video for a bad regulator for audio power on another Sanyo mainboard?

[Ltank]

Re: Sanyo dp50741 main board j4je

Protection circuit is shutting it down. There are voltage test points on the main board with white stars to make finding them easier. Place ohm meter black lead to chasis ground then use red lead to test each voltage test point for the short. I fixed one last week. The 3.3 vdc was shorted to gnd. It was the HDMI chip. Hard to find because it is obsolete but available. I took one from a bad board with other problems, I included a different service manual that includes your set with info other info that will help. See page 4 to test SMPS.

[ricosavy]

Re: Sanyo dp50741 main board j4je

Ok i looked at trouble shouting guide to test power supply.disconnect everything the only thing i left connected was cable p25 from power supply to d25 on logic board. And none powers to sc and ss are present and my 15v are not present either.weird thing is when everything is connected i get no green light only when i disconnet this cable will i get any reponse from power button then it shuts off after a few.does this mean i have a bad logic board

[ricosavy]

Re: Sanyo dp50741 main board j4je

This diode when i touch either side to its heat sink it gives me a reading of .4 ohm is it shorted or is this heat sink live.here is a pic of it

[ricosavy]

Re: Sanyo dp50741 main board j4je

Does anyone know how to test p1540edg i have two that have 14v on both left and right legs and the middle has nothing.there is also one that has .8 on one leg and 4.9 other and 4.9 on middle leg.see pics

[ricosavy]

Re: Sanyo dp50741 main board j4je

Other pic

[ricosavy]

Re: Sanyo dp50741 main board j4je

Well i recieved a power supply will try it tomorrow.i did do a quick test on bench and had all my voltages present the regulator i took a pic of earlier had 14 v on both legs left and right and nothing in middle leg.now on new board left and right legs had different reading one was 2.5 v and 14v and the center one had 14v so there is something wrong with the old one for sure.

[Ltank]

Re: Sanyo dp50741 main board j4je

There is a possability that the audio amp is shorted loading the voltage regulator. Remove the voltage regulator and check for shortsto gnd

[SlickClick]

Re: Sanyo dp50741 main board j4je

have you seen the norcal715 video for a bad regulator for audio power on another Sanyo mainboard?

I think you should follow TW's path of the video how to on youtube...
I saw this a while back when troubleshooting a no power on issue with a sanyo aswell... its a small 6-pin surface mount IC that burns up physically on the outside or fries internally either way; its a good place to start...

My issue turned out to be rotting components on the PSU due to the unit being outside... ended up using the screen for a frakenvision...

[ricosavy]

Re: Sanyo dp50741 main board j4je

I replaced the power supply and tv is up and running.Since my friend needed his tv i will troubleshout power supply at component level when i get more time to work on it.The troubleshooting guide says it is rarely the power supply that goea bad on this sanyo tv but in my case it was the power supply.Usually something in main board.

[jdaproduca]

Re: Sanyo dp50741 main board j4je

If your power supply is darfon b159-001 check cap C214 to make sure it is still good. I fixed a DP50741 which did not respond to power button or show any kind of power lights just had 5v stby voltage.

[kevinm34232]

Re: Sanyo dp50741 main board j4je

Protection circuit is shutting it down. There are voltage test points on the main board with white stars to make finding them easier. Place ohm meter black lead to chasis ground then use red lead to test each voltage test point for the short. I fixed one last week. The 3.3 vdc was shorted to gnd. It was the HDMI chip. Hard to find because it is obsolete but available. I took one from a bad board with other problems, I included a different service manual that includes your set with info other info that will help. See page 4 to test SMPS.

Also just had one with a shorted HDMI IC6600, causing 3.3V protection shut down. Check D6702 for 3.3V on plug in. At first I though it was the audio IC, I was looking for 12V at D1668 like it said in SM, but it looks like that should also be 3.3V.
HDMI IC6600 = TDA9996HL/C1 and mainly from China on eBay.