Panasonic TX-L42U2 LCD 7 blinks - power supply problem

[Hombre]

First thing: it is a LCD not plasma

So, i got this TV, and when I try to turn it on relays don't click and it starts to blink 7 times. According to the manual it is missing SUB3.3V.
It was strange that i can't hear relay clicking so i started to look that part of circuit on the power supply. Found out that two diodes D812 and D813 are damaged and also Q803.
So i replaced the diodes, but the transistor is making me problems, because i can't figure it out which specifications it should have. There is one more on this power supply, it is Q800 and it has same panasonic number like the damaged one: B1ABNF000011. But i am not able to find anything about this transistor.
The thing is that, if i put in place of Q803 this good one, it is posible to switch relays on with 2,15V which is the TV_SUB_ON voltage from mainboard to turn on power supply. If i put any other NPN in position of Q803 i need 5,8V (that is a stdby voltage) to turn on relays completely.
I was able to turn on complete power supply (forced with 5.8V) and everything is working properly, except this NPN switch, and i have no idea which one I can use as a substitute for B1ABNF000011.

Also tv turned on and is working fine but only if i turn on power supply with forcing the main relays.
I tried to change this transistor with 2N2222, 2N3904 and some others, but neither of them is turning on completely with TV_SUB_ON signal (2,15V), but with 5,8V they are on completely, relay switches and power supply starts.
But i would preffer to find one that will turn on with 2,15V
Coil of relays is 5Vdc, and when both of them switch over current is around 350-400mA on that line.

I complicated things as allways but hopefully someone will understand me and give me a solution for this 2 relays and their transistor

Thanks guys!

[R_J]

Re: Panasonic TX-L42U2 LCD 7 blinks - power supply problem

What is the marking code on the transistor?
If it is a W it could be a 2sb1219
if it is a *1G it could be PMBTA06 (used in other panasonic power supplies)

[Hombre]

Re: Panasonic TX-L42U2 LCD 7 blinks - power supply problem

I think it's S Z, but can't tell for sure, it's hard to read it.
This 2SB1219 is a PNP so i think that one is not an option.

I can try with PMBTA06, but can i be sure it's going to work?
Is there a posibility that something else is making problems?

Found in a service manual of TX-L42U10E same circuit, and there is 2SD0601ASL with the same function, so i will try to find this one or one with similar specs and try it, it should work hopefully

[R_J]

Re: Panasonic TX-L42U2 LCD 7 blinks - power supply problem

I did't look close enough on the 2sb1219.
I did find 2PC4617 with marking ZS, which looks similar to the 2sd0601a
I would think the TV_SUB_ON voltage would be 3.3 volts when on, that should be enough to turn on the transistor
If it is only 2.15v you might have a problem on the main board, check that the 3.3 volts is ok

[Hombre]

Re: Panasonic TX-L42U2 LCD 7 blinks - power supply problem

Update.

In place of damaged transistor I installed BC817-40 and TV powered on. Even with 2.15V TV_SUB_ON signal, which should be right voltage for this signal.

Hopefully someone else with similar problem can fix it with this info