Sanyo DP42849 - No Power At All

[tom66]

Re: Sanyo DP42849 - No Power At All

I think STR-chip is defective. You can try replacing it.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

Okay. Should I pull it out of circuit and test it, or just go ahead and order it?

[tom66]

Re: Sanyo DP42849 - No Power At All

With power off, you can test from pin 5 to 3 on ohms mode, in circuit, then pull device and check again out of circuit.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

On Ohms 200, I get 15.6.

Is there anything else I should test? And were any of the caps bad or should I leave them alone?

[tom66]

Re: Sanyo DP42849 - No Power At All

15.6 ohms is very bad. It looks like you have found the fault...
The caps are very high quality on this model, I would not expect them to be at fault.

[multimeter]

Re: Sanyo DP42849 - No Power At All

so what went wrong then ?

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

Roger that. Any advice on removing this chip from the board?

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

so what went wrong then ?

Looks like that STR chip - IC901.

[multimeter]

Re: Sanyo DP42849 - No Power At All

this is your power ic,pin one will have a dot on the surface

count anti-clockwise,you will have to check pins 3 and 5 ,with your meter on 200 ohm resistance,report the reading back,when you have done the voltage testing

sorry my fault,black probe on pin 3 red on pin 5,it may need removing to get a good reading,but see what the resistance is between those 2 pins

power off and unplugged for that test

man, this takes a lot of dexterity.

Black lead on pin 3, red lead on pin 5 - i got a "1".

no short to ground there,there is a mosfet in there ,sort that out in a bit

page #2

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

Yeah, pretty sure I fudged that up. I had the wrong pin 5.

[vinceroger69]

Re: Sanyo DP42849 - No Power At All

well we all learn by making mistakes at times i would add some fresh solder to each pin of the ic your removing then use your solder wick these are also very usefull in my opinon if radio shack sells them http://www.amazon.com/Parts-Express-.../dp/B0002KRAAG

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

well we all learn by making mistakes at times i would add some fresh solder to each pin of the ic your removing then use your solder wick these are also very usefull in my opinon if radio shack sells them http://www.amazon.com/Parts-Express-.../dp/B0002KRAAG

Well, I've definitely learned a lot and I'm really enjoying it, aside from the frustration.

I actually ordered that sucker last night with the expectation that I'd never be able to get this IC up. I've been practicing on an old Genesis board I had lying around, and I had such a hard time getting the caps out. The solder would hardly soak up into the wick. I managed to get 3 of them out, and I'm quite sure I've ruined them all.

But the solder around this IC came up much easier. Different quality of solder, maybe. I dun know.

Hopefully I haven't ruined the board or anything - I did make an effort not to leave the iron tip on it for no more than 5-10 seconds.

And I got the same readings with it off the board, so I guess it's a dead spider.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

Oh, is Digikey the best place to get it? And is this the correct part: http://www.digikey.com/product-detai...69H-ND/3661844

. . . should I order 2 just in case?

Thank you all!

[vinceroger69]

Re: Sanyo DP42849 - No Power At All

thats why before i remove any faulty parts if possible i add fresh solder first makes it easier for me any way and im still learning as well.

[tom66]

Re: Sanyo DP42849 - No Power At All

One thing of note, just noticed this, is that is 8-DIP type. Ideally you use 7-DIP which has that missing lead. You can still use 8-DIP but you would have to cut off the excess lead, which has no function.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

One thing of note, just noticed this, is that is 8-DIP type. Ideally you use 7-DIP which has that missing lead. You can still use 8-DIP but you would have to cut off the excess lead, which has no function.

Thanks for pointing that out. I noticed it as well yesterday and had a chat with a rep before ordering it - he checked it and confirmed that pin 6 is not used. I'm assuming that means it just isn't there. If not, I'll have to cut it.

Just out of curiosity, what could have happened to it to cause it to stop functioning?

Thanks again for your help!

Hmmm - http://www.geek.com/chips/ic-failure...recipe-554945/

[tom66]

Re: Sanyo DP42849 - No Power At All

I won't go into too much detail but basically it's a random probability that a device will fail.

So a device might have an MTBF (mean time between failures) of 50,000 hours, that's pretty typical for consumer electronics. Does this mean it will last 50,000 hours? Not necessarily. It means that if you had 50,000 widgets in the field, on average, one would fail every hour.

Other things, it can also be damaged by a power surge or moisture getting into the device before the soldering process, leading to early failure.

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

Thanks for the info, Tom. Hopefully it's just a random failure, and not indicative of a larger problem with the TV.

Got part in today. From ground pin to pin 5, I'm getting a "1" on it, whereas on the old one I got 15.X.

Is that okay?

[tom66]

Re: Sanyo DP42849 - No Power At All

Yep, that looks a lot better.
If you want to avoid smoke, you can try this trick:
https://www.badcaps.net/forum/showthread.php?t=32748

[NihonNoir]

Re: Sanyo DP42849 - No Power At All

Thanks, but that's a bit over my head.

I've bought 2, so if something happens, I'll have a backup at least.

When I solder this chip back on the board, will that diode that reads as shorted (but good out of circuit) read correctly again?