Matsui M32LW409 no picture but sound

[Andyd1970]

Hi Guys,

I have just taken in a Matsui M32LW409, that has sound but no picture, I have switched it on in the dark and you can see the screen being illuminated.

Any thoughts please

[tom66]

Re: Matsui M32LW409 no picture but sound

Checked the T-con fuse?

[Andyd1970]

Re: Matsui M32LW409 no picture but sound

Hi had thought that but could not see anything obvious that was like a surface mounted fuse, I have noticed a components called FP1. Is that the fuse?

[tom66]

Re: Matsui M32LW409 no picture but sound

How about some pictures of the boards and chassis layout?

[Andyd1970]

Re: Matsui M32LW409 no picture but sound

Hi Tom,

See pictures, the TCON was behind a large metal frame that has the PSU and AV board.

[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.

[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

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

[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

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

[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

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,

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, 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

FP1 right side O/C

FP1 left side 000.5 Ohms, getting continuity beep from meter

[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.

[tom66]

Re: Matsui M32LW409 no picture but sound

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

[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

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.

[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.