Sanyo DP46840

[budm]

Re: Sanyo DP46840

I looked at the the way the schematic is drawn, some connections as shown does not make sense at all.
I will have to look at the PCB trace layouts to see the actual connections.
As you can see (PAGE 45), IC800 PIN48 (it has 100K resistor to 5VSTBY pull up) will activate the P-FAILED signal when its input goes low, so any one of the Diodes (OR gate setup as shown on page 5) on the Cathode side will be low when the power supply does not work which will cause the Diode to be forward bias (ON, the Cathode side of the Diode will have resistor network to set the trip point, IE R1683 is set to have just enough voltage on it to keep the D1671 in reverse bias) and take pin 48 to be around 0.6Vdc. When all the power supplies are working, those Didoes will be reversed bias (OFF).
So when the 13VDC output is only 3V or so, that is not enough to keep the Diode off.
If you remove D1671 then that way the P FAIL will not be fed to the PIN 48 IC800, then the TV should come on but no sound.

[kevinm34232]

Re: Sanyo DP46840

Hmm OK. So removing D1671 would be bypassing P FAIL for that circuit? If that's the case that's great, I will attempt to repair regulator and reconnect those traces on the amp and see what happens first. If not then I'll go that route.

[budm]

Re: Sanyo DP46840

Yes.

[kevinm34232]

Re: Sanyo DP46840

And maybe stupid question but I havent looked for it yet, guessing D1671 is a SMD, just heat it up and pull off the board?

[budm]

Re: Sanyo DP46840

I add more solder to both ends and move your soldering tip back and forth real quick while using a small tweezer to lift the Diode off the board.

[kevinm34232]

Re: Sanyo DP46840

If I remove that diode, and I do that regulator mod, will that affect anything if the mod works? Id like to try to get the audio working if possible.

[budm]

Re: Sanyo DP46840

What we trying to do is to get the TV running without the sound first just to verify for sure that where the shutdown is coming from. Then we can do the mod or replace that bad IC.

[kevinm34232]

Re: Sanyo DP46840

I tried removing this diode, (it's on the bottom of the board). But I couldn't get it to move, I tried adding more solder, wiggling with tweezers but no luck. Didn't want to break anything. Not sure if it's because both sides need to be heated at same time??

[budm]

Re: Sanyo DP46840

It is a very small diode not sure why you are having a hard time removing it, I thought it is on the top side of the board, may be I seeing it incorrectly on the service manual.

[selldoor]

Re: Sanyo DP46840

The legs may be bent on the bottom side. If you have any solderwick remove as much solder as possible then you will see why it wont go through the hole. If no solderwick
just work one side get a cocktail stick or similar and lever up just a fraction as you melt the solder- keep the leverage on till the solder resets then do the other leg - just a fraction and so on till its out.

[budm]

Re: Sanyo DP46840

I thought is it SMD type? I need to check the service manual for sure.

[catfish69]

Re: Sanyo DP46840

What would happen if i cut the power input to the ic1670? would that shut down the audio circuit completely and allow the tv to work without sound of course?..

[stupidstuff]

Re: Sanyo DP46840

Ok Got SM Thanks - will see if I can split it up

Here are some BIG excerpts for budm.

Oh man. Can you get me a full schematic picture of the main board? I need all the capacitor locations and values. I de-soldered my caps to test them and the kittens got at my baggie with the caps and list I made up. I don't know what happened to my list so now I don't know where all the capacitors go back :-(

[stupidstuff]

Re: Sanyo DP46840

SM Split into 3 zipped sections - all need to be downloaded before it will work.

This is for a DP42840 not a DP46840. Does it matter? Can I use this manual to find capacitor locations and values for DP46840?

[lilmonk3]

Re: Sanyo DP46840

Was this ever fixed? The fellas at the VFW just brought me their dp42840.. Hit power button, can hear cycle on power board and then it shuts down.. No backlights when it does this.. Just green power light and then a few seconds later click and it goes off.. Getting correct readings on PWB before it shuts down..

[lilmonk3]

Re: Sanyo DP46840

They did say that the screen when Black and white a couple of weeks ago for a brief moment and now its doing this

[lilmonk3]

Re: Sanyo DP46840

Kevin??

[kevinm34232]

Re: Sanyo DP46840

Mine is "fixed". Audio circuit was bad and rather than replace the main board, with the help of others here and elsewhere, I cut traces going to the audio amp IC and also added a 15v voltage regulator as it appeared the original one was bad too. This keeps the TV from shutting down and I use my external home theater system for sound.. What model TV is yours and what chassis #?

[lilmonk3]

Re: Sanyo DP46840

Dp42540 Chass. P42840-01

[kevinm34232]

Re: Sanyo DP46840

Mine was chassis 00, did you get service manual??