thosiba 32DT2U1 dead

[laloualfa]

Hi, my tv.is a thoshiba model 32DT2U1

when i turn the tv on the green light turn on for 10 sec and turn off, nothing happens, no screen no sound.
I checked the voltages on the PS board
standby 5 vdc is always there, with the tv on,3.3 vdc on the PWR,12 and 24 vdc and nothing on DIM and INV, after 10 sec the green light turn off, no screen no sound nothing.
I bought a new controller board, number is 431C4A51L11 the tv turn on and everything works great for an hour, I turned it off and turn it on again and nothing,no screen.
the green light turn on for 10 sec and turn off.

after a while I put back the old board and give him a trie and the tv turn on, worked great, turned it off and on and nothing, black screen.

any idea what going on?

[clapp]

Re: thosiba 32DT2U1 dead

please post pictures of the boards.

[budm]

Re: thosiba 32DT2U1 dead

http://www.shopjimmy.com/catalogsear...oshiba+32DT2U1

Are those the correct boards used in your TV?

[laloualfa]

Re: thosiba 32DT2U1 dead

[budm]

Re: thosiba 32DT2U1 dead

"standby 5 vdc is always there, with the tv on,3.3 vdc on the PWR,12 and 24 vdc and nothing on DIM and INV" So you do have 5VSTBY and PWR signal but you do not have other signal or Voltages, but how about the ACD (AC DETECT), 0VDC?
Pictures provided by shopjimmy.

[laloualfa]

Re: thosiba 32DT2U1 dead

on ACD, almost nothing .08vdc

[freakaftr8]

Re: thosiba 32DT2U1 dead

This model is known for bad BGA solder connections all over the mainboard. I fixed a few by the "oven" method. 450 for 8 mins. Problem is even though it repaired it the buttons melted. Still functional but not good for resale. I would focus on trying some heat all over the board including the main processor to see if the set comes up. Could use a hairdryer. Keep away from the buttons thou.

[budm]

Re: thosiba 32DT2U1 dead

OK, I look at some of the Toshiba power supply circuits, the ACD should be >2.5V for normal operation.
You can pull the ACD wire off the power supply board connector and use 1K between 5VSTBY and the ACD wire to see if the TV will stay on.

[laloualfa]

Re: thosiba 32DT2U1 dead

is that means that 2.5vdc should comes from the power supply?

[budm]

Re: thosiba 32DT2U1 dead

is that means that 2.5vdc should comes from the power supply?

Yes, there is detection circuit that tells the main board that AC Voltage, or B+, or the PFC Boosted Voltage (in this case your TV does not have PFC) feeding the TV is not too low to run the TV.
If you look at the board you can see that Q202 is the one that send this ACD signal.

[laloualfa]

Re: thosiba 32DT2U1 dead

I found Q201 the black small one but not Q202

could it be intermittent?

[budm]

Re: thosiba 32DT2U1 dead

"could it be intermittent?" That is why I am telling to use the resistor to narrow down the cause of the problem to see if it is the ADC signal is the problem or not.
Q202 is close to the connector that goes to the main board:
https://www.badcaps.net/forum/attach...5&d=1445491077

[laloualfa]

Re: thosiba 32DT2U1 dead

I disconned the ACD connector from the PSU and took 5vdc via 1k ohm resistor to the orange wire that goes to the main board.
turn on the tv:
light turn on 5 sec and off .
nothing,no screen no sound .

[budm]

Re: thosiba 32DT2U1 dead

So if you measure the DCV on that end of the resistor, it shows >2.5VDC? If it does then we may have problem on the main board some where.
if you get the TV to stay on next time, take the DCV readings of the connector so we will know what the normal Voltage should be.

[laloualfa]

Re: thosiba 32DT2U1 dead

thanks,
I will try it tomorrow

[laloualfa]

Re: thosiba 32DT2U1 dead

This model is known for bad BGA solder connections all over the mainboard. I fixed a few by the "oven" method. 450 for 8 mins. Problem is even though it repaired it the buttons melted. Still functional but not good for resale. I would focus on trying some heat all over the board including the main processor to see if the set comes up. Could use a hairdryer. Keep away from the buttons thou.

thanks,
I will try it tomorrow

[laloualfa]

Re: thosiba 32DT2U1 dead

So if you measure the DCV on that end of the resistor, it shows >2.5VDC? If it does then we may have problem on the main board some where.
if you get the TV to stay on next time, take the DCV readings of the connector so we will know what the normal Voltage should be.

I measured the DCV at the end of the resistor it was 2.5vdc

and for no reason the day after, the tv turn on and read the voltage on PS board:

inv 3
dim 2.2
ACD .08

[freakaftr8]

Re: thosiba 32DT2U1 dead

This leads me to believe that it is a BGA connection bad somewhere or a general loose solder connection

[laloualfa]

Re: thosiba 32DT2U1 dead

This leads me to believe that it is a BGA connection bad somewhere or a general loose solder connection

what BGA means?

[budm]

Re: thosiba 32DT2U1 dead

I measured the DCV at the end of the resistor it was 2.5vdc

and for no reason the day after, the tv turn on and read the voltage on PS board:

inv 3
dim 2.2
ACD .08

Is that reading with the resistor still feed the ACD pin of the main board and ACD pin of the power supply wire not connected?