Toshiba 46sl417u main board issue

[shadetreetrader11]

Does anyone know what part generally goes bad on the Toshiba model 46sl417u? Main board is a pe0953a or v28a001251a1. Turn power on no picture, no backlight or sound. No blinking standby lights If I hook the connector from the power supply to the led driver board crooked so the 3.3 vdc isn't hooked up the back light will come on. But as soon as I hook the connector up it shuts off. This board is hard to find and i'm getting a little desperate.

[CapLeaker]

Re: Toshiba 46sl417u main board issue

Measure the voltages on each pin of the PSU where the main board plugs in and report back with the voltages measured and the corresponding pin out.
Also send some hi res pics, so we can see it.
Could be anything from failed eeprom to no power of some sort, a short or blown main IC. Search for your board on ebay... there was one and also a repair service.

[adgor]

Re: Toshiba 46sl417u main board issue

Does anyone know what part generally goes bad on the Toshiba model 46sl417u? Main board is a pe0953a or v28a001251a1. Turn power on no picture, no backlight or sound. No blinking standby lights If I hook the connector from the power supply to the led driver board crooked so the 3.3 vdc isn't hooked up the back light will come on. But as soon as I hook the connector up it shuts off. This board is hard to find and i'm getting a little desperate.

Do you mean the 2.9vDim on pin#1 (PJ860 to J1), pin #10 on CN90 (main) ? Is the resistance low on that DIM line with the TV unplugged? Unplug CN90 and check pin #10 on Main. A low resistance = bad main. This model has had power supply problems.... so is the standby voltage low or unstable (CN90 pin #4 = 5vsb on main)? If yes, then you might have power supply problem. Some kits are available.

PJ860= Power Supply
Out
1. <2.9V Dim
2. <5.2V BL On
3. Option
4. Gnd.
5. Gnd.
6. Gnd.
7. <24V
8. <24V
9. <24V

CN90 Main
1. >3.1V AC Det.
2. <3.07V Pwr. On
3. <3.1 TV On
4. >5V SB***
5. Gnd.
6. >24V LNB
7. Gnd.
8. Gnd.
9. <5.2 BL On
10. <2.9 Dim

[shadetreetrader11]

Re: Toshiba 46sl417u main board issue

Ok guys

PJ860-POWER OFF
1. 0 545K OHMS
2. .070 VDC
THE REST WERE GOOD

PJ860 POWER ON
1. 3.01 THEN BACK TO ZERO VOLTS WHEN THE RELAY CLICKS ON THE POWER SUPPLY.
I USED THE MIN MAX ON METER
2. 70 MIL AGAIN

CN91 ON MAIN BOARD
1. 3.3
2. 3.26
3. 3.28
4.5.14
5. GND
6. 24 V THE BACK TO ZERO AFTER RELAY CLICKS
7.0
8.0
9 70 MIL VLT
10.0

[budm]

Re: Toshiba 46sl417u main board issue

Really confused readings.
Can you please report the DCV reading in the same format as used by ADGOR?
How about the pictures?

[shadetreetrader11]

Re: Toshiba 46sl417u main board issue

What would you like me to take a pic off? All the boards or one in particular.

[budm]

Re: Toshiba 46sl417u main board issue

The whole back side of the TV so we can see how all the boards are connected together, then the pictures of the whole power supply board and the closed up around the connector so we can see the pin labels.
BTW, do you also have the P/N of the power supply board?
Is this your power supply board?
http://www.shopjimmy.com/catalogsear...shiba+46sl417u

[CapLeaker]

Re: Toshiba 46sl417u main board issue

Ok guys

PJ860-POWER OFF
1. 0 545K OHMS
2. .070 VDC
THE REST WERE GOOD

PJ860 POWER ON
1. 3.01 THEN BACK TO ZERO VOLTS WHEN THE RELAY CLICKS ON THE POWER SUPPLY.
I USED THE MIN MAX ON METER
2. 70 MIL AGAIN

CN91 ON MAIN BOARD
1. 3.3
2. 3.26
3. 3.28
4.5.14
5. GND
6. 24 V THE BACK TO ZERO AFTER RELAY CLICKS
7.0
8.0
9 70 MIL VLT
10.0

You really want us to know where those readings belong without a pinout?

[shadetreetrader11]

Re: Toshiba 46sl417u main board issue

Every time I try to get you some pictures it tells me that i have an invalid file.
I'll keep trying, Sorry guys

[shadetreetrader11]

Re: Toshiba 46sl417u main board issue






Figured it out, Don't Ask. Let me know if you need more

[CapLeaker]

Re: Toshiba 46sl417u main board issue

Right now you don't have BLon (backlights). That signal comes from the main board.

[shadetreetrader11]

Re: Toshiba 46sl417u main board issue

Correct. But if I hook the connector that goes to the driver board up crooked so only the 24v is making a connection with the power supply board. Then the backlight comes on. As soon as I hook it up correctly is faults out.

[CapLeaker]

Re: Toshiba 46sl417u main board issue

The PSU has probably a pull up resistor, so when you unhook the main board, plug the PSU in, the backlights come on. So your PSU is good. What you could try doing is to take the BLon pin out of the connector, take a 1k resistor and jump 5v into that connector on the PSU. See what happens

[shadetreetrader11]

Re: Toshiba 46sl417u main board issue

I tried that and the backlight comes on for a sec then shuts off again. I checked the voltage coming from the driver board to the psu and there is 3.3v on the BL pin. And as soon as I plug the connector in correctly the 3.3v drops to zero. The only way the back light stays on is if I unhook the BL pin and the PDIM pin at the same time. I checked the resistance from BL pin to ground and it isn't shorted. And the PDIM to ground was the same.

[budm]

Re: Toshiba 46sl417u main board issue

I tried that and the backlight comes on for a sec then shuts off again. I checked the voltage coming from the driver board to the psu and there is 3.3v on the BL pin. And as soon as I plug the connector in correctly the 3.3v drops to zero. The only way the back light stays on is if I unhook the BL pin and the PDIM pin at the same time. I checked the resistance from BL pin to ground and it isn't shorted. And the PDIM to ground was the same.

That is because as CAP has explain, the Driver board has pull-up resistor but the main board is stuck LO so when you hook up properly the main board pull that line low and not allowing it to go high, it does not mean the line is shorted, it means that the processor is not turning off (when it is supposed to) the switched transistor to allow the line to go HI.

[CapLeaker]

Re: Toshiba 46sl417u main board issue

I guess you need a new main board

[budm]

Re: Toshiba 46sl417u main board issue

If he is able to get the backlights to stay on, if other functions of the TV main board are OK, then he should be able to see the pictures and have sound, and everything else working normally, if not the he more that just bad BL-ON and bad DIM control problem on the main board.

[shadetreetrader11]

Re: Toshiba 46sl417u main board issue

There is no way to track down the faulty part on the main board? I just ordered a eprom for a couple bucks. I thought I would try it just for the heck of it. At this point what could it hurt. I'm willing to try anything you think might be the problem.

[CapLeaker]

Re: Toshiba 46sl417u main board issue

If he is able to get the backlights to stay on, if other functions of the TV main board are OK, then he should be able to see the pictures and have sound, and everything else working normally, if not the he more that just bad BL-ON and bad DIM control problem on the main board.

I was thinking about this on one of my earlier posts too.

There is no way to track down the faulty part on the main board? I just ordered a eprom for a couple bucks. I thought I would try it just for the heck of it. At this point what could it hurt. I'm willing to try anything you think might be the problem.

So when you took the BLon and the DIM pins out of the connector, the backlights stayed on, you said. Did you have picture and sound?

[shadetreetrader11]

Re: Toshiba 46sl417u main board issue

No sound or video.