Toshiba 22DL833G Not power on.

[Andreasbest]

Hello.
I got a Toshiba 22DL833G that doesn't power on and all i got is a flashing red/green led.
Unfortunately i can't found any service manual anywhere so we must go on based on experience.
Although i suspect that something is wrong with the PSU, also there are no any visible popped or leaked caps.
Here are some hi resolution photos of the pcb.

[kasfamily]

Re: Toshiba 22DL833G Not power on.

the second photo u157 chip (I think) very crooked set

[budm]

Re: Toshiba 22DL833G Not power on.

Can you get the numbers as printed on the SMPS IC 700?
Please also provide the pictures of the bottom side of the power supply board.
Is there a thermal transfer pad on that U157?

[Andreasbest]

Re: Toshiba 22DL833G Not power on.

Can you get the numbers as printed on the SMPS IC 700?
Please also provide the pictures of the bottom side of the power supply board.
Is there a thermal transfer pad on that U157?

First of all thank you very much for the reply and the help. I pictured the IC700and the bottom side of the PSU and yes the U157 has a thermal transfer pad on top of it.

the second photo u157 chip (I think) very crooked set

Thanks for the reply too, i'll try to found the datasheet of the u157 and measure the voltages, although not sure if the voltages from psu are correct.

[budm]

Re: Toshiba 22DL833G Not power on.

Spec of the SMPS IC 700 (ICE3BR0665).
Check the DC voltage at the Cathode (banded side) of D708 and the chassis Gnd to see if the voltage is fluctuating.
BTW, this power supply is an always on power supply.

[Andreasbest]

Re: Toshiba 22DL833G Not power on.

Spec of the SMPS IC 700 (ICE3BR0665).
Check the DC voltage at the Cathode (banded side) of D708 and the chassis Gnd to see if the voltage is fluctuating.
BTW, this power supply is an always on power supply.

I just checked both AC and DC sides of the psu board and i see several voltages, caps take voltage too although i don't know if they are correct.
Seems that psu is ok, i'm afraid about a mainboard fault. I'll check the DC on the diode you advised me and i'll come back with news shortly.

[Andreasbest]

Re: Toshiba 22DL833G Not power on.

The D708 has 11.5v , the same on c730, c729 and c731.
Also here is a diagram of the psu pcb i hope it will helps us, already started checking the voltages.
So far i'm seeng that d712 has the correct voltage 23.5v but i miss some voltages from PL703, the pins 7, 8, 9 have 0v and i get voltage only from pin 5 (5v).
I have pulled the pcb from tv and measure on the bench, not connected on the rest of the boards, just to let you know.

[budm]

Re: Toshiba 22DL833G Not power on.

You may want to read this thread in the mean time, also take the voltage reading without the main board connected and see what you get.
https://www.badcaps.net/forum/showth...t=30405&page=3

[Andreasbest]

Re: Toshiba 22DL833G Not power on.

You may want to read this thread in the mean time, also take the voltage reading without the main board connected and see what you get.
https://www.badcaps.net/forum/showth...t=30405&page=3

All of the above measurments are without any other board connected, only psu with mains plug connected.
I just want to determine that the psu pcb is good and if yes to proceed on mainboard....

[budm]

Re: Toshiba 22DL833G Not power on.

OK, PL703 connector:
pin 7, 8 are 12VCC switched outputs
pin 9, 10 are +5v_vcc switched outputs
The switched out put will produce output Voltages when PS_ON (ACTIVE HIGH >2.5VDC) signal from the main board is present at pin 17 of PL703 so see if you have PS_ON siganl from the main board or not.
The 12V, 24V, and STBY_5V are always on outputs.

[Andreasbest]

Re: Toshiba 22DL833G Not power on.

OK, PL703 connector:
pin 7, 8 are 12VCC switched outputs
pin 9, 10 are +5v_vcc switched outputs
The switched out put will produce output Voltages when PS_ON (ACTIVE HIGH >2.5VDC) signal from the main board is present at pin 17 of PL703 so see if you have PS_ON siganl from the main board or not.
The 12V, 24V, and STBY_5V are always on outputs.

After connecting it with the rest of the board i get.
Pin 7 only 2.13, pin 8 0v , pin9 5v , pin 10 5v and pin 17 3.36v (i think this is a sign that there is signal).

[budm]

Re: Toshiba 22DL833G Not power on.

"Pin 7 only 2.13, pin 8 0v" OK, you need to verify the readings on pin 7 and pin 8, as you can see in the diagram, both pin 7 and pin 8 should be tied together and connected to the INDUCTOR L703 switched 12VCC output. Unless the diagram is not correct.

"pin 17 3.36v" PS_ON is OK.

[Andreasbest]

Re: Toshiba 22DL833G Not power on.

7 and 8 are tied? Damn what i've done wrong.Ok going to measure again and verify with buzzer that is tied.

[budm]

Re: Toshiba 22DL833G Not power on.

7 and 8 are tied? Damn what i've done wrong.Ok going to measure again and verify with buzzer that is tied.

If we can trust that diagram, look at the bottom side of the board and see if 7 and 8 are connected together, give us a good closed up picture of the bottom side where the connector so I can see too. We need to verify where 7 and 8 are connected to.
We are getting close to the problem.
Do not use buzzer mode since resistance as high as 50~100 Ohms (depend on the meter design) can still make the meter buzz, should look for <1 Ohm reading on the meter.

[iranem]

Re: Toshiba 22DL833G Not power on.

yes Budm, swithed out 12V_VCC not 12V

[Andreasbest]

Re: Toshiba 22DL833G Not power on.

Ok i just figure out that the diagram is upside down, meaning that where i thought the pin 1 was is the 19.
So from the beginning pin 7 and 8 indeed tied and 11.36v, pin 9 5v and pin 17 shows 0v, pin 18 is grounded so i verified the correct view of the pin layout.

[budm]

Re: Toshiba 22DL833G Not power on.

"pin 17 shows 0v" 0V when power switch is activated? It should change state between HIGH and LOW. It should go HIGH (>2.5Vdc) when the unit is ON.
But so far you do get the switched 12V at pin 7&8 so the power supply is working.

[Andreasbest]

Re: Toshiba 22DL833G Not power on.

"pin 17 shows 0v" 0V when power switch is activated? It should change state between HIGH and LOW. It should go HIGH (>2.5Vdc) when the unit is ON.
But so far you do get the switched 12V at pin 7&8 so the power supply is working.

I see, i think that psu is ok too. So i made a little research about the main board 17MB60 and found the service manual of a tv set that uses the same mainboard. Check on page 66 , i think this is a good place to begin

[Andreasbest]

Re: Toshiba 22DL833G Not power on.

TV returned as "unrepairable", the problem was on mainboard and as the customer told me after 10 days "i was trying to upgrade with several firmwares...." so then i understood that the mainboard was bricked from software so nothing to repair, except from replacing the board.
Clost the thread, thank you all for the help!

[budm]

Re: Toshiba 22DL833G Not power on.

That is bad when the customer does not tell you what they did before giving it to you to repair the set. I got that a lot also, could have save lots of times.