TOSHIBA 46G310U 5V power only

[102mm]

need a little Help please..

I have a TOSHIBA 46G310U that will not output anyoltage other than the 5V.
when the TV is plugged in the power button will illuminate but nothing else.. I checked the main filter cap and its holding at 169V but spikes to 270v for a sec when i press the power button. I have checked every diode and FET but i cant seem to find anything wrong with this thing.. I don't know where to look

[ammarben]

Re: TOSHIBA 46G310U 5V power only

the main filter cap must be 390/400vso the pfc circuit is not running
check Q2 and D3

[tech2014]

Re: TOSHIBA 46G310U 5V power only

the main filter cap will be at around 160V in standby then around 400 in full on mode.

[102mm]

Re: TOSHIBA 46G310U 5V power only

ok thanks, but where is that? I have replaced the IC U2 and i get about 320V at the cathode of D801 while the anode sits at 167V.

[tech2014]

Re: TOSHIBA 46G310U 5V power only

The filter cap is the largest cap on the primary side, or bottom right side of the board. When measuring anything on the primary side, use the negative lead of the filter cap as ground reference.

Q2 will be on a heatsink.

[102mm]

Re: TOSHIBA 46G310U 5V power only

The filter cap is the largest cap on the primary side, or bottom right side of the board. When measuring anything on the primary side, use the negative lead of the filter cap as ground reference.

Q2 will be on a heatsink.

I measured directly from the filter cap for the voltages when i got the 167... the Negative on the filter cap is what i used when i measured the 320Vat D801 too.. i'm stumped..

[tech2014]

Re: TOSHIBA 46G310U 5V power only

Is there a PS_ON or VS_ON pin on any connector on the secondary side?

[budm]

Re: TOSHIBA 46G310U 5V power only

There are labels on the power supply secondary side connectors' pins, so please report all the DCV reading of each pin with pin's name next to each reading so we can see what are missing.
http://assets.shopjimmy.com/media/ca...5/75024143.jpg

[102mm]

Re: TOSHIBA 46G310U 5V power only

Connector P802 - ON /OFF
measurements taken using the GND pin on that connector.
BLON 3.2V / 0
#Dim .528 / 0
#ACD .104 /0
#PWON 3.3V/ 0
5V 5.09 / 5.106
12V .154/0
GND
24V .145/ 0

Main Cap holds at 175V at power off at power on it jumps to 270V for half a second then back down to 175V.

[budm]

Re: TOSHIBA 46G310U 5V power only

OK, so the power supply is getting the PS-ON OK, so when you check the DCV between the two legs of the main filter cap you do not see >360VDC only 270V?
The 12V/24V power supply need PFC boosted Voltage to work.
Try disconnecting the cables to the inverter board and see if the boosted Voltage will be more than 360VDC.

[102mm]

Re: TOSHIBA 46G310U 5V power only

OK, so the power supply is getting the PS-ON OK, so when you check the DCV between the two legs of the main filter cap you do not see >360VDC only 270V?
The 12V/24V power supply need PFC boosted Voltage to work.
Try disconnecting the cables to the inverter board and see if the boosted Voltage will be more than 360VDC.

it's only 270V.. I have everything disconnected except the main board cable.

[budm]

Re: TOSHIBA 46G310U 5V power only

If that is the case then you have the problem some where in the PFC Voltage booster section. I cannot find the diagram for the power supply board.
So the D2 as the other has suggest you to test is OK?
Can I also see the good clear pictures of the bottom side of the board?

[102mm]

Re: TOSHIBA 46G310U 5V power only

If that is the case then you have the problem some where in the PFC Voltage booster section. I cannot find the diagram for the power supply board.
So the D2 as the other has suggest you to test is OK?
Can I also see the good clear pictures of the bottom side of the board?

This is about the best i can get with the pictures.. what do you mean the D2?
which IC is the PFC booster.. i Thought it was U2 (A6059H) I changes that one with no luck.

[budm]

Re: TOSHIBA 46G310U 5V power only

U2 str-6059 is SMPS the standby power supply IC. Did you look up the spec sheet before replacing the IC? you can easily see that the IC drives the little power transformer.
U1 (SMD) SMPS IC for 12V/24V

There is way too much glare in the pictures, the SMD IC for the PFC Controller is near PFC MOSFET Q2. Need better pictures.

[102mm]

Re: TOSHIBA 46G310U 5V power only

U2 str-6059 is SMPS the standby power supply IC. Did you look up the spec sheet before replacing the IC? you can easily see that the IC drives the little power transformer.
U1 (SMD) SMPS IC for 12V/24V

There is way too much glare in the pictures, the SMD IC for the PFC Controller is near PFC MOSFET Q2. Need better pictures.

OK sorry for the delay, attached are pics of the power supply. i hope they are better.. are you saying that U1 (LD6571B) is possibly the problem? I have replaced everything but that IC with no succes.

[budm]

Re: TOSHIBA 46G310U 5V power only

OK sorry for the delay, attached are pics of the power supply. i hope they are better.. are you saying that U1 (LD6571B) is possibly the problem? I have replaced everything but that IC with no succes.

You need to check DCV of U3 between the VCC oin and the GND pin to see if it is getting the DCV to run it when PS-ON is present.
U1 SMPS IC is for 12V/24V power supply.

[102mm]

Re: TOSHIBA 46G310U 5V power only

You need to check DCV of U3 between the VCC oin and the GND pin to see if it is getting the DCV to run it when PS-ON is present.
U1 SMPS IC is for 12V/24V power supply.

with the PS off i get 1.6V between pins 6 and 8. once i connect the PS on it quickly jumps to 6.5 then drops to .2, but starts to rise slightly.. when i disconnect the PS ON it starts to rise back slowly back up.. I also checked the voltage using the filter cap Neg, with the same results. the other pins on U3 have 0 volts

[budm]

Re: TOSHIBA 46G310U 5V power only

But what is the P/N of U3 PFC IC? So you have the P/N and able to find out the VCC and GND pin of U3?

"with the PS off i get 1.6V between pins 6 and 8. once i connect the PS on it quickly jumps to 6.5 then drops to .2, but starts to rise slightly.. when i disconnect the PS ON it starts to rise back slowly back up.. I also checked the voltage using the filter cap Neg, with the same results. the other pins on U3 have 0 volts" Are you talking about U1 SMPS (LD6571B) IC or U3 PFC IC?
I did not find the spec sheet for U1 LD6571B, do you have it?

[102mm]

Re: TOSHIBA 46G310U 5V power only

But what is the P/N of U3 PFC IC? So you have the P/N and able to find out the VCC and GND pin of U3?

U3 is FAN6961 those pins are the VCC and GND.

I don't know what i did but now i'm blowing the main fuse.. back to square one...

[102mm]

Re: TOSHIBA 46G310U 5V power only

I did not find the spec sheet for U1 LD6571B, do you have it?

sorry that was a typo it's L6571B..
I just replaced Q101 & Q102 (12N50E), The voltage on the main cap jumps to over 370V with PS ON. then falls back to 170. Still no 12 or 24V only 5V.