Toshiba Regza - 42RV555D

[cholzberger]

Hi,

just troubleshooting this monitor,

The Power Supply is a Toshiba - PE0620 Version: V28A000841A1

i found the resistor r809 to be open.

i expect it should be at 3.7k ohm. now i wonder if this is correct.

[tom66]

Re: Toshiba Regza - 42RV555D

It is normal for that resistor to appear open, it is usually around a few meg-ohms, it is a safety resistor.

What is the fault with the TV?

[cholzberger]

Re: Toshiba Regza - 42RV555D

the screen never turns on,
standby led is on, 4.9V and 3.5 V are going to the logic board.
but there is no POW_PRO, POW_SIG... (when i press or unpress the button)

at the moment iam searching for open fuses, but everything i checkd this far looks good.

logic-board is a Toshiba - PE0649V28A000865A1

[tom66]

Re: Toshiba Regza - 42RV555D

The main board is getting standby voltages, but never sends power signal?

If you get a 470 ohm resistor, you should be able to control power on line without the main board connected, which will eliminate the PSU from the problem.

[cholzberger]

Re: Toshiba Regza - 42RV555D

Update on this one,

the powerboard has ~ -3 V on POW_PRO and ~ - 4.9V on AC_DET of the lower connector.

And there is -5 V on POWER_TV. which should turn on the main power supply i guess, but there is no other voltage comming up.

Can you give me some hin on what else should be jumpered? i attached an picture of the power board connectors but iam not really shure where to put the 3v / or i guess -3 V on this tv.

Another sympthom:
I hear a high frequent sound comming from the powerboard which dissapears when i press the power button.

[tom66]

Re: Toshiba Regza - 42RV555D

When you press the power button, does POWER_TV change at all?

[cholzberger]

Re: Toshiba Regza - 42RV555D

Nope no change when i press the button?!

But i got other (strange) readings this time
POW_PRO is at -1.6 Volts and AC_DET is at -3.5 Volts

POWER_TV also only gets -3.5 Volts this time?!

It makes no difference if i use casis or gnd pin as ground.

really weird behaviour?!

[tom66]

Re: Toshiba Regza - 42RV555D

Have you got the black probe in COM, red probe in Volt/Ohm?

[cholzberger]

Re: Toshiba Regza - 42RV555D

argh sorry my fault, all are positive voltages.

but 1.6 and 3.5 Volts only, i am not really sure what to search for next?! bad transformator?

[tom66]

Re: Toshiba Regza - 42RV555D

Since the power on voltage does not change, I suspect the main board is at fault here. Using a 470 ohm resistor, you can change the power on voltage and check all the power supply outputs come to the right voltage. You need to connect from POWER ON to GROUND, then you can test the 24V, if it then comes to 23.5 - 24.5V the PSU is most likely OK. But if it doesn't, I would suspect the main board is attempting a self-test of PSU (it is common with Toshiba) and this is failing.

[Chrissp]

Re: Toshiba Regza - 42RV555D

Hi. I have the same problem, only 1,6V on pow_pro, 3.5V on ac_dec, but
power_tv get s 3,5 volt, change to 0, then 2,5 then 3,5 Volt again. Standby LED is on,
but nothing else is going. My tv had a lightning strike. (3.3 Ohm resistor and bridge rec. changed). The standby ic reads 15,6 V. 390V on main cap.
What else can i do?

(sorry for my english, i m from germany)

Greetings, Christian

[Chrissp]

Re: Toshiba Regza - 42RV555D

Found it. hdmi chip on mainboard is burned. Think i need a new mainboard.