Toshiba 47zv650u no power at all!!

[rmoody]

I have this model 47zv650u Toshiba lcd and when plugged in there is no power at all. No lights on front of panel or anything. I'm guessing this is my power supply but wanted to get a second opinion. Haven't found a service manual yet so can't really check any voltages yet. Obvious fuses have been checked and are good.

[rmoody]

Re: Toshiba 47zv650u no power at all!!

It appears that I have power on my primary side of the PB but nothing on the secondary. If anyone can help me find a service manual that would help a lot.

[PlainBill]

Re: Toshiba 47zv650u no power at all!!

It appears that I have power on my primary side of the PB but nothing on the secondary. If anyone can help me find a service manual that would help a lot.

No luck on finding a service manual. While they look complex, the power supplies are sometimes easy to troubleshoot. At this point I suggest you attach pictures of the top and bottom of the power supply using 'Manage Attachments' (below the text entry area). Sharp, well lit pictures make it easier for us to help you.

PlainBill

[rmoody]

Re: Toshiba 47zv650u no power at all!!

OK, will get a few for ya. I'm getting 33 volts on the primary when going off of chassis ground.

[rmoody]

Re: Toshiba 47zv650u no power at all!!

here's a full pic of the board. It appears that i'm getting nothing on the DC side.

[rmoody]

Re: Toshiba 47zv650u no power at all!!

and a shoddy pic of the back. If you want a more focused area, let me know and i'll get it.

[PlainBill]

Re: Toshiba 47zv650u no power at all!!

Interesting layout. Messy, but interesting.

Close to the center of the board is a small transformer with a yellow strip of tape across the top. GC1 TRS02 DK is printed on the tape. Just above it is a 7 pin IC labeled with Q840 outlined in white. I believe that is the standby SMPS controller. What is the part number of that IC?

PlainBill

[rmoody]

Re: Toshiba 47zv650u no power at all!!

A6169
sk972
16dc

[rmoody]

Re: Toshiba 47zv650u no power at all!!

Got a question for you. I don't think it matters but this diode in the pics D875 checked right and i reversed the leads to see if it would read 0V and it didn't it started slowly creeping up to OL. Is this normal? Most diode's i've checked will check a small voltage one way and swap leads and it reads 0V. I removed the diode from the circuit and checked again and it read like a normal diode, low volt on one side and zip with reversed leads.

[cadillacman]

Re: Toshiba 47zv650u no power at all!!

in ciruit there are other components(capacitor most likely) causing your odd reading.

as long as it checks ok out of cicuit youre good.

[PlainBill]

Re: Toshiba 47zv650u no power at all!!

A6169
sk972
16dc

You have a winner!!! That is an STR-A6169, an integrated SMPS controller / power FET. The datasheet is here.

Fortunately the pins are marked on the board. Pin 3 is Ground. What are the voltages on pins 1, 2, 4, and 5? Do NOT check the voltage on pins 7 and 8.

PlainBill

[rmoody]

Re: Toshiba 47zv650u no power at all!!

You have a winner!!! That is an STR-A6169, an integrated SMPS controller / power FET. The datasheet is here.

Fortunately the pins are marked on the board. Pin 3 is Ground. What are the voltages on pins 1, 2, 4, and 5? Do NOT check the voltage on pins 7 and 8.

PlainBill

Pin1-.005
pin2- .005
pin4 -.498
pin5 - .054

Doesn't sound too good to me but IDK.

[rmoody]

Re: Toshiba 47zv650u no power at all!!

Looks like from the datasheet that my smps is bad. I'm having trouble breaking it down in digikey though.

[PlainBill]

Re: Toshiba 47zv650u no power at all!!

Looks like from the datasheet that my smps is bad. I'm having trouble breaking it down in digikey though.

You might be premature. You can trace this down yourself, or provide pictures of the surrounding area (top and bottom of the board). Pin 5 SHOULD be at the same voltage as the mains filter cap. The application note shows it connected directly, but there may be a resistor between them.

If you are REALLY brave, try measuring the voltage from pin 3 to pin 7 or 8.

The STR-A6169 is available from Amazon at a very popular price - $19.99 - a 1000% markup. You might also try searching for it under the Sony part number - 6-600-279-01

PlainBill

[rmoody]

Re: Toshiba 47zv650u no power at all!!

You might be premature. You can trace this down yourself, or provide pictures of the surrounding area (top and bottom of the board). Pin 5 SHOULD be at the same voltage as the mains filter cap. The application note shows it connected directly, but there may be a resistor between them.

If you are REALLY brave, try measuring the voltage from pin 3 to pin 7 or 8.

The STR-A6169 is available from Amazon at a very popular price - $19.99 - a 1000% markup. You might also try searching for it under the Sony part number - 6-600-279-01

PlainBill

Well i got Ballsy and checked the 7 and 8 pins and had nothing. That chip doesn't seem to be getting anything. Shouldn't i be getting an input to one of those pins? Checked the surrounding resistors and they seemed to be ok and none are shorted. Here's a couple pics for you. Is there any way to check the IC if i pulled out of circuit?
That amazon price is ridiculous.

[PlainBill]

Re: Toshiba 47zv650u no power at all!!

Well i got Ballsy and checked the 7 and 8 pins and had nothing. That chip doesn't seem to be getting anything. Shouldn't i be getting an input to one of those pins? Checked the surrounding resistors and they seemed to be ok and none are shorted. Here's a couple pics for you. Is there any way to check the IC if i pulled out of circuit?
That amazon price is ridiculous.

The next step is to check F840. The safest approach is to measure the voltage across the large (mains filter) cap (C820), holding the black lead on the - terminal and the red lead on the +. IF you get 0 volts (as in less than .01), it is safe to measure the resistance of F840. Otherwise you can move the red probe to measure the voltage on each side of F840. Obviously, it should be the same.

If F840 is open, do NOT jumper it with a wire. There is a significant chance Q840 is shorted pin 8 to pin 3.

PlainBill

[rmoody]

Re: Toshiba 47zv650u no power at all!!

c820 has no voltage, F840 has no resistance. Not open just reads 0.00 What is the F stand for. I'm used to that being a fuse.

[PlainBill]

Re: Toshiba 47zv650u no power at all!!

c820 has no voltage, F840 has no resistance. Not open just reads 0.00 What is the F stand for. I'm used to that being a fuse.

It is. I'm going to have to take a break. The bed is looking irresistible.

With power connected, what is the voltage across C20?

PlainBill

[rmoody]

Re: Toshiba 47zv650u no power at all!!

C20? can't find a c20

[PlainBill]

Re: Toshiba 47zv650u no power at all!!

C20? can't find a c20

C820

PlainBill