Sanyo Turns off when sound turned up

[shorteddiode]

Sanyo Model DP47460 wors great and will play non-stop if you do not turn the sound up past 38. I have replace pretty much all the caps on the power and main board. (The caps with the red tops are the new ones) Does not matter which input you use the magic number is still 38. The tv will turn back on but if you don't switch inputs to a no signal and lower the volume it will turn back off. After about three shut downs the set has to be unpluged for awhile before it willl turn back on. I am stumped I did check the resistors on the power supply too, no problem found.

Power board # 1LG4B10Y04800
MainBoard # 1AA4B10N24700

[retiredcaps]

Re: Sanyo Turns off when sound turned up

Does not matter which input you use the magic number is still 38.

Since it looks like you can reproduce this quite easily, I suggest taking before and after voltage measurements of all your connectors and voltage regulators on the main board.

For example, set volume to 1, record all your voltage measurements. Do the same for 10, 20, 30, and 37.

See if there are any significant changes between those 5 settings. You may spot something abnormal?

[tom66]

Re: Sanyo Turns off when sound turned up

My bet would be the green caps - C630H1 and one I can't see, under the heatsink. I have seen this problem on Vestel TVs (different PSU but similar topology), and it is usually those two caps.

Oh, and if the sound is quiet, does it still cut out at 38?

[f67bird]

Re: Sanyo Turns off when sound turned up

It's most likely IC1670. This is an 8 pin surface mount ic. It has a ground pad underneath the body of the ic that is also soldered to the board.
It drops 24 volts down to 13 volts to run the audio output circuit.
It's located on the top side of the board about an inch to the right from the speaker connector. The sanyo part number is QXXGA0500165P.

[f67bird]

Re: Sanyo Turns off when sound turned up

I took your photo of the main board and drew a black outline around the ic.
The ground pad below the ic makes it tough to remove from the board without
hot air.

[shorteddiode]

Re: Sanyo Turns off when sound turned up

Thanks guys, I'll try the voltage checks. I have hot air, (My wife tells me I am full of it)
So I'll order the chip and change it out. I'll let eveyone know the results

[shorteddiode]

Re: Sanyo Turns off when sound turned up

Well I looked to buy the chip but can't find a supplier. Anyone have a lead on Sanyo parts?

[kevinm34232]

Re: Sanyo Turns off when sound turned up

There may also be an IC001 audio amp that could be the problem.. You'll have to check the 13v line and see if it drops off...

[budm]

Re: Sanyo Turns off when sound turned up

I remember that now when I was helping you on that Sanyo DP42840 where I posted my notes as shown in post 4.

[kevinm34232]

Re: Sanyo Turns off when sound turned up

Yep. Mine would not turn on at all and 13v line was low due to shorted audio amp IC.

[f67bird]

Re: Sanyo Turns off when sound turned up

Well I looked to buy the chip but can't find a supplier. Anyone have a lead on Sanyo parts?

I think you will have to get it from Sanyo themselves.
I have a number to try: Sanyo parts phone #: 18008775036 ext1485

The number on the part is LV5806MX-TLM-H but you will have to use the Sanyo part #QXXGA0500165P
Sanyo is the original manufacturer of the part. It's a step-down switching regulator...pdf here

Let us know what they say.

[BoJaXz]

Re: Sanyo Turns off when sound turned up

I have the same tv, except that when i turn mine on, it just shows the sanyo start-up screen, then shuts off again. i'm new to the whole "fixing tvs" scene, but i'm learning quickly. any thoughts on what the problem would be? i'm trying to do it myself to save $100 on what might or might not be the problem.

[Clydeuk]

Re: Sanyo Turns off when sound turned up

Bit messy but if you can isolate the supply for the audio stage, try feeding it off a separate source, 12v will probably be fine. If it goes past the point where shut off occurs you probably have a fault in the power supply. It could be that there is something amiss with the 24v rail since the supply is derived from there, or some protection circuit is malfunctioning.

[BoJaXz]

Re: Sanyo Turns off when sound turned up

I did notice that with the ac plugged in, tv off, the 24v rail had 24v on a couple of the negative terminals. I wish I could find a diagram of the main board and ps board that tells what goes to what.

[BoJaXz]

Re: Sanyo Turns off when sound turned up

Does anyone have a service manual for this model?

[johnboy1313]

Re: Sanyo Turns off when sound turned up

Sorry I'm late. Try this.

[BoJaXz]

Re: Sanyo Turns off when sound turned up

Thank you!!

[BoJaXz]

Re: Sanyo Turns off when sound turned up

so i got another chip for the mainboard. it isn't exactly the same one. the original has a ground pad under it, i'm not sure what the significance is of it. but i replaced it with one that doesn't have a ground pad for some reason. and now i get even lower voltage coming out of it from 2.8v to 1.6v

[BoJaXz]

Re: Sanyo Turns off when sound turned up

It's a lv58063mx the original chip only says v5806. Doesn't give much to go off.

[nubleet]

Re: Sanyo Turns off when sound turned up

This info is golden! Has anyone had any luck with this repair? I received a DP55360a with the same issue as BoJaXz (Displays splash screen the turns off). The unit has the same N8TE main board. I have reflowed the BGA on the board then i found this thread.