SANYO DP37647 Sound no Picture

[lilmonk3]

It powers on just fine with sound, no pic or back lights.

Power board readings:
Cn2 goes to main
PS_on 4.9 v
5vsb 5.0 5.0 v
12v 12.0 12.1 v
24v 24.1 24.1 v
CN4 goes to inverter
24.0v
24.1v
24.1v
24.0v
MAINBOARD from Power board
K8B
white 4.9v
12.0v
12.0v
24.1v
24.0v

K6R goes to inverter
white 3.3v
3.3v
0.3v
4.3v

[tom66]

Re: SANYO DP37647 Sound no Picture

No backlight or no image on lit screen?
Check inverter fuse.

[lilmonk3]

Re: SANYO DP37647 Sound no Picture

Fuse and transformers all in spec .. I should have said I already tried a replacement inverter..

[tom66]

Re: SANYO DP37647 Sound no Picture

Inverter VIN measures 4.3V? That is too low but you do have 24V on your power board. Check if there are fuses on the power board - maybe one there.

[lilmonk3]

Re: SANYO DP37647 Sound no Picture

Yes I have 24v on power board .. The 4.3 is coming from the main to the inverter

[tom66]

Re: SANYO DP37647 Sound no Picture

Can you post a clear shot of the inverter? It doesn't look like the 24V is getting to the inverter - I'm suspecting a fuse on the PSU somewhere (and fuses can be deceptive, looking like anything...) This TV probably uses the 24V for the audio circuit as well, many do.

[lilmonk3]

Re: SANYO DP37647 Sound no Picture

I was just looking over the Power board and found this.. Would this ferrite bead cause a problem

[tom66]

Re: SANYO DP37647 Sound no Picture

I don't think so - it's just a bit of ferrous material wrapper around a wire. It's to reduce the interference the TV can kick out with regards to radios etc.

[lilmonk3]

Re: SANYO DP37647 Sound no Picture

Its a long inverter.. Here are a few pics

[lilmonk3]

Re: SANYO DP37647 Sound no Picture

One thing that made me scratch my head is... On the power board there is a cable 24v connection CN5 that is empty and there is also and empty connection on the inverter.. Is there SUPPOSE to be a cable going between the 2....

[tom66]

Re: SANYO DP37647 Sound no Picture

OK, test the voltage as indicated in the image. Red probe on the red highlighted pin, black on the black highlighted pin.

You can test the voltage on any of the main caps on the inverter.

[tom66]

Re: SANYO DP37647 Sound no Picture

Hmm I wonder. Perhaps the owner tried to fix their TV?

[lilmonk3]

Re: SANYO DP37647 Sound no Picture

Thats what I am wondering... The set didnt SEEM to have been opened but ya never know

[tom66]

Re: SANYO DP37647 Sound no Picture

Do the check I mentioned - if it's zero volts or near enough zero, you can always solder individual wires between the PSU and inverter or crimp your own cable.

[lilmonk3]

Re: SANYO DP37647 Sound no Picture

24v on all caps on inverter

[tom66]

Re: SANYO DP37647 Sound no Picture

So I think it's OK. That plug on the PSU is probably for a slave inverter, and on the other inverter is probably for a different PSU, or for use as a slave inverter in some way. Check all the transformers on the inverter next as you have Darfon ones and they often fail.

[lilmonk3]

Re: SANYO DP37647 Sound no Picture

Transformer all are good.. One of the first things I checked

[tom66]

Re: SANYO DP37647 Sound no Picture

Check the primaries of the transformers too. I've never seen one fail, but wouldn't rule it out. You are expecting close to 0 ohms.

[tom66]

Re: SANYO DP37647 Sound no Picture

Oh, and did you check this fuse too?

[lilmonk3]

Re: SANYO DP37647 Sound no Picture

Secondary all 0.3, primary 2.15 ,all white fuses 1.0