Toshiba 55ZV650U REGZA sound but no picture

[CapLeaker]

Re: Toshiba 55ZV650U REGZA sound but no picture

The wants you to measure the DC voltage direct at the legs of the main filter capacitor. It is the biggest, high voltage capacitor(s) on the primary side of the PSU. Look for some 450V caps. Be careful there can be 400V DC on there when the PSU is up and running. All measurements in the primary side of the PSU, your ground reference point is the negative post of the primary main filter capacitor. The ground reference on the secondary (output rails) is plain GND.

[dick_barton]

Re: Toshiba 55ZV650U REGZA sound but no picture

With the power to the TV off, put your meter on Ohms and place red lead on one side of the fuse and black lead on the other side of the fuse and tell us the reading.

Fuse is in the red box. See photo. (T 3A written on it)

[dick_barton]

Re: Toshiba 55ZV650U REGZA sound but no picture

One of the mains filter capacitors looks as though it's failing!!

Can you post a sharp picture of the underside of the power supply board.

[dick_barton]

Re: Toshiba 55ZV650U REGZA sound but no picture

Dick Barton
help me out here plz....

Where do I check the voltage on both sides of the white ceramic fuse on the Tcon board. Where is or which is the ceramic fuse?

where do i check the voltage on the 12VLCD pins.

In Post #6 the area boxed in red on each photo is where you check the voltages.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

The wants you to measure the DC voltage direct at the legs of the main filter capacitor. It is the biggest, high voltage capacitor(s) on the primary side of the PSU. Look for some 450V caps. Be careful there can be 400V DC on there when the PSU is up and running. All measurements in the primary side of the PSU, your ground reference point is the negative post of the primary main filter capacitor. The ground reference on the secondary (output rails) is plain GND.

CapLeaker thanks for the reply.

But please help me out, how do I identify the main filter capacitor and when you say the primary side, is that the underside of the board?

I will venture a little to figure it out and post the results right away. If not, I ll wait for some guidance......if possible try to make reference to the pictures I posted....Im very visual.

Thx again

[dick_barton]

Re: Toshiba 55ZV650U REGZA sound but no picture

If you post a clear, sharp picture of the underneath of the board we can show you where to check the main filter capacitor.

[dick_barton]

Re: Toshiba 55ZV650U REGZA sound but no picture

Mains filter capacitors as in photo with X identifying them both.

[dick_barton]

Re: Toshiba 55ZV650U REGZA sound but no picture

There seems to be a dark spot on the resistor which I have marked. Can you measure the ohmic value.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

Mains filter capacitors as in photo with X identifying them both.

Got it you guys are amazing........
I checked Caps C820 an C821 with the TV plugged in but I unplugged other plugs to the board in order to get to the back of the Caps. This is the results:

DC on the multimeter was 165V for both caps marked with and X.

Did I do the test right by unplugging the other plugs in order to get to the back of it and just leave the AC plugged to the TV.

and just to make sure I was doing it right to see what kind of reading I would get on AC, I tried it and got 360 on AC on both caps.

[dick_barton]

Re: Toshiba 55ZV650U REGZA sound but no picture

I fairly certian they are the expected readings. Now for that resistor value. And don't forget to also check the TCON fuse resistance.

[CapLeaker]

Re: Toshiba 55ZV650U REGZA sound but no picture

See the white line that goes across the power supply? It will indicate the primary vs the secondary side of the power supply. In the picture above, the lower part and the right side is the "hot" or primary side. THe top left is the secondary or "cold" side. Same on the back side of the power supply. Why hot and cold? The primary side is connected to the mains, the cold side is separated.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

See the white line that goes across the power supply? It will indicate the primary vs the secondary side of the power supply. In the picture above, the lower part and the right side is the "hot" or primary side. THe top left is the secondary or "cold" side. Same on the back side of the power supply. Why hot and cold? The primary side is connected to the mains, the cold side is separated.

Thk for the explanation concerning the board.......you made it easy to understand.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

Hey fellas,
Please standby, as soon as I get back home (doing my duty as a son on Mothers Day)......lol.......I'll post:

1- picture of the back side of the power supply
2- Value for the resistor with the black spot
3- The result of the fuse on the T-Con

If there is anything else I can test or take a picture of please let me know and I ll add them on my next post thanks.

It feels like Im actually getting somewhere with this issue .

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

Ok some more results: T-con = .3 is the reading when the TV is off and I also did it with the TV on incase it was of any use , it was 5.0.

Value for the resistor with the black spot.......no reading

I also add the picture of the back side of the board which I hope will help pin point the culprit.

Also add a picture of the Cap C821 in case you can see the ever so slight bow on the top.

I hope this info will help.

Someone asked about the 12v, so I looked around on the board an notice the plug at the extreme top right of the board and noticed something that said 12v right above the standby 5v. So, I decided to check it ..........nothing no voltage .....no reading.

[dick_barton]

Re: Toshiba 55ZV650U REGZA sound but no picture

I reckon that you should be considering replacing C821

The Tcon fuse . You read 5V dc on both sides of the fuse?

Did you measure the resistor with the black spot with the set off and you meter leads across each leg (either way) with your meter set to ohms If it read nothing then you need to replace it. Are the colour bands on that resistor brown, black, yellow, gold (100K)

There are also fuses marked f870, f895 and f840 which you can check with the set off using your meter set to ohms.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

I reckon that you should be considering replacing C821

The Tcon fuse . You read 5V dc on both sides of the fuse?

Did you measure the resistor with the black spot with the set off and you meter leads across each leg (either way) with your meter set to ohms If it read nothing then you need to replace it. Are the colour bands on that resistor brown, black, yellow, gold (100K)

There are also fuses marked f870, f895 and f840 which you can check with the set off using your meter set to ohms.

Tcon fuse TV off = .2 both ways
Tcon fuse TV on = 5resistance

Tcon fuse TV on .01 DC volts

Resistor with black spot gives me reading with the TV off set on ohms gives me nothing and when I switch the probe around I get a negative reading starting at around -1600 and kind of settles at -1480
yes the brown black yellow gold

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

can you help me locate the fuses marked f870, f895 and f840

[CapLeaker]

Re: Toshiba 55ZV650U REGZA sound but no picture

Tcon fuse TV off = .2 both ways
Tcon fuse TV on = 5resistance

Tcon fuse TV on .01 DC volts

Resistor with black spot gives me reading with the TV off set on ohms gives me nothing and when I switch the probe around I get a negative reading starting at around -1600 and kind of settles at -1480
yes the brown black yellow gold

All resistance readings are with the tv off. If you measure DC volts on the cold side, put your meter in DC mode, put the black probe to GND or chassis GND and with the red probe both sides of the fuse.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

All resistance readings are with the tv off. If you measure DC volts on the cold side, put your meter in DC mode, put the black probe to GND or chassis GND and with the red probe both sides of the fuse.

Thanks CapLeaker...

But from what i learnt so far the resistor he is referring to seems to be on the hot side. So I gather it should done with the TV on.

Are all these results making sense at all. Could the cap be finished a making a chain reaction?

[CapLeaker]

Re: Toshiba 55ZV650U REGZA sound but no picture

The resistor is open. Open resistor = bad. Also I would change that capacitor, as it is at the end of it's life.
There may be something else in circuit too that is bad. So more testing has to be done.
Again, in order to measure resistance, turn the TV off, unplug it and put your probes on the component you want to test.
Warning: Some meters will explode if you use them in Ohms mode and connect them to AC mains voltage. Be very careful in the primary, some parts can have 400V DC on there, some heat sinks maybe actual hot (as in power) too.