Matsui M32LW409 no picture but sound

[Andyd1970]

Re: Matsui M32LW409 no picture but sound

Hi Guys,

I tested the Caps with a meter CP1 it was O/C CP3 was short circuit with the meter on ohms. I replaced CP1 but still got the same no picture but sound, FP1 is O/C.

I would like to replace the fuse and CP3 where do I find them on ebay? what value is the fuse and CP3?

Thanks for all your help guys.

[Th3_uN1Qu3]

Re: Matsui M32LW409 no picture but sound

I wasn't saying he should leave the set running that way if it works. But it definitely can be tested like that, to check if it's good, or there are more issues.

[tom66]

Re: Matsui M32LW409 no picture but sound

I do power supply testing at work. Usually using MLCCs. It's easily possible missing that capacitor could adversely affect the stability of the converter. They are not decoupling capacitors. They are the input capacitors for a boost converter (AVDD, 15V @ 1.5A.)

It is OK for a quick test, but running continuously could cause a problem in the future.

[Th3_uN1Qu3]

Re: Matsui M32LW409 no picture but sound

They are local decoupling capacitors. It is common practice to put them, they are not 100% required. When repairing cellphones there are often problems caused by shorted capacitors. Trust me, nobody bothers to replace those little buggers. The offending cap is simply scraped off with a blade and the phone goes back to the customer.

Replacing these capacitors is recommended but not mandatory. And you can use anything that fits in their place. They are not critical like on a power supply or VRM.

[tom66]

Re: Matsui M32LW409 no picture but sound

There is a reason the engineers put two capacitors on there. Omitting one may work, but it could cause further issues down the line. The stability of the dc-dc converter could be affected adversely.

[Th3_uN1Qu3]

Re: Matsui M32LW409 no picture but sound

Just replace them with ones of similar size. Capacity is not critical - in fact, if you replace the fuse now, the set will likely run just fine without those capacitors. Btw, one of them is likely still good - just use the continuity beeper of your multimeter to find the shorted one. Then you can put the good one back on.

[tom66]

Re: Matsui M32LW409 no picture but sound

One of them is probably short. You can test each on a capacitance meter to be sure. (One use for such a meter! Don't use an ESR meter unless it will read out capacitance too.) One capacitor will give a sensible reading for capacitance, the other should not. They will almost certainly be the same value.

The package format is 1210 and the voltage rating will be 16V or more. I would guess capacitance of around 10~33uF, but I would suggest testing them if possible.

[Andyd1970]

Re: Matsui M32LW409 no picture but sound

Hi Guys,

I have removed CP1 and CP3 and have O/C at each end of FP1 now.

So do I take that I need to replace the two caps? How can i find out the value

I still had the panel connected and everything else was connected. I did not try Tom's bits as thought best to try one thing at a time.

[tom66]

Re: Matsui M32LW409 no picture but sound

+1
Also try CP30,CP31
And test with panel ribbons removed (eliminate shorted panel possibility)

[Th3_uN1Qu3]

Re: Matsui M32LW409 no picture but sound

Something is hard shorted over there. Remove ceramic capacitors CP1 and CP3 and see if the short goes away.

[Andyd1970]

Re: Matsui M32LW409 no picture but sound

FP1 right side O/C

FP1 left side 000.5 Ohms, getting continuity beep from meter

[tom66]

Re: Matsui M32LW409 no picture but sound

Ok, so try testing from each end (with TV power OFF) the resistance to the chassis ground, on the 2000 ohm range.

[Andyd1970]

Re: Matsui M32LW409 no picture but sound

Hi Tom,

Scrub all that I had not reconnected the ribbon cable from the Tcon to the main board ! OK so the following readings

FP1 right side 12.3v

FP1 left side 000.3mV

[tom66]

Re: Matsui M32LW409 no picture but sound

Ok, see if you can find a 12V supply on the PSU, it should be on a pin on the power board to main board connector.
What is the part # of the main board? 17MB.....

[Andyd1970]

Re: Matsui M32LW409 no picture but sound

Hi Tom,

Back light is on and sound is being produced,, it is a slightly different reading

Left side of FP1 000.1mV and on right side of FP1 its around 60-90mV

[tom66]

Re: Matsui M32LW409 no picture but sound

Is that on - i.e. with backlight and sound?

[Andyd1970]

Re: Matsui M32LW409 no picture but sound

Hi Tom,

With the set powered up I get no voltage reading on the left side of FP1 but on the right side I get around 100mv, I had black probe to the chassis.

[tom66]

Re: Matsui M32LW409 no picture but sound

Never jumper a fuse. You can buy the fuses from eBay or CPC, about £3.

[Andyd1970]

Re: Matsui M32LW409 no picture but sound

OK, FP1 is open circuit, I will check voltages. With TV's would is be OK to solder a link over FP1 to prove it or could that cause more damage?

[tom66]

Re: Matsui M32LW409 no picture but sound

Mmm, Vestel junk, I see.
FP1 looks to be a fuse, I'd start there.
Also, try checking DC volts both ends of fuse, with boards all connected.