Daewoo LCD 42" model DLP-42C1

[bohaboha]

Re: Daewoo LCD 42" model DLP-42C1

Here i am again.

When plugged there is only the red LED switching to green non stop on the front panel

the screen is black and nothing happend att all no clicking or anything else.

nothing happend too when pushing on the different button on the side.

now some mesure on the psu board and the main board

the Psu board :

CN3 :
12V =0.00VDC
12V =0.00
GND =0.00
GND =0.00
5VS =5.11VDC
P/O =0.00VDC
GND =0.00VDC

CN5 :
O/B =0.00VDC
DIM =0.00VDC
GND =0.00VDC
GND =0.00VDC
GND =0.00VDC
GND =0.00VDC
24V =0.00VDC
24V =0.00VDC
24V =0.00VDC
24V =0.00VDC

CN6 :
O/B =0.00VDC
DIM =0.00VDC
GND =0.00VDC
GND =0.00VDC
GND =0.00VDC
GND =0.00VDC
24V =0.00VDC
24V =0.00VDC
24V =0.00VDC
24V =0.00VDC

CN4 :
DIM =0.00DCV
B/O =0.00DCV
NC =3.29DCV
GND =0.00DCV
GND =0.00DCV
NC =0.01DCV
12V =0.01DCV
12V =0.01DCV

CN2 :
30V =0.30DCV
30V =0.30DCV
GND =0.00DCV
GND =0.00DCV

on some capacitor :

C25 =3.87VDC
C32 =5.11VDC
C31 =5.11VDC


it is not possible to reach the bakside of the big capacitor when it is on the tv but i did a

test on the table and it was 328VDC.

The power button or any other not working so just plugg in to start

now some test on the main board

IC507
1 =0.00DCV
2 =0.00DCV
3 =0.40DCV

IC 508 :
1 =0.00DCV
2 =0.03DCV
3 =0.40DCV

IC711
1 =5.09DCV
2 =3.29DCV
3 =0.00DCV

P803A this one is connected to CN2 on the psu and there is no labelle
1 =0.00DCV
2 =0.00DCV
3 =0.30DCV
4 =0.30DCV

P804A
A/dim =0.00dCV
BLK_ON=0.00DCV
LVDS_SW=3.29VDC
GND =0.00DCV
GND =0.00DCV
5V_LVDS =0.01DCV
5V_LVDS =0.01DCV
NC = 0.01VDC

hope this help thank you

[tom66]

Re: Daewoo LCD 42" model DLP-42C1

OK, P/O is continuously low. Beg borrow or steal a 100~470 ohm, unplug PSU connector from main board side, and wire the resistor from 5VS to P/O, rails should come up, PFC cap should rise to 390V or so.

[bohaboha]

Re: Daewoo LCD 42" model DLP-42C1

Ok, with 100ohm,the PFC cap C23 have 322dcv i took the mesure on the +and - pole of

the capacitor. it is the same result with the jump i did se early post

something have to be wrong in the Q1,Q5 and IC1 area but i do not know

[tom66]

Re: Daewoo LCD 42" model DLP-42C1

Do the main outputs rise at all?

[bohaboha]

Re: Daewoo LCD 42" model DLP-42C1

but you tell me to unplugg the PSU from the main?

[tom66]

Re: Daewoo LCD 42" model DLP-42C1

Yes, but you should still be able to test the outputs...

[bohaboha]

Re: Daewoo LCD 42" model DLP-42C1

ok now when i plugg in i get a very diffuse mixed colored screen for 2 or 3 seconds then

bak to black.

the mesure on the main :

IC 507
1 =0.00DCV
2 =2.49DCV
3 =5.22DCV

IC 508

1 =0.00DCV
2 =3.26DCV
3 =5.21DCV

IC 711
1 =5.09DCV
2 =3.29DCV
3 =0.00DCV

[tom66]

Re: Daewoo LCD 42" model DLP-42C1

That may be expected to see that from main board if it not expecting power.
Does 24V come up?

[bohaboha]

Re: Daewoo LCD 42" model DLP-42C1

yes now the 24V and even the 30V on the PSU are ok

[bohaboha]

Re: Daewoo LCD 42" model DLP-42C1

so it allways a problem on PSU but can you point a specific area ?

[tom66]

Re: Daewoo LCD 42" model DLP-42C1

If you have good PSU voltages it's unlikely to be the PSU. The red/green blinking to me makes me think of mian board issue -- could be firmware problem or some other issue.

[bohaboha]

Re: Daewoo LCD 42" model DLP-42C1

but the actuel voltage on the PSU is due to 100 ohm resistor cross 5vs and P/O if it is off

then the voltage will fall down again or shall i leave the resistor there so long?

[tom66]

Re: Daewoo LCD 42" model DLP-42C1

Yeah, but if the main board is faulty it won't send the P/O signal. The 100 ohm resistor proves the PSU is working, at least partially (still unsure about PFC, but I think it should still work.)

[bohaboha]

Re: Daewoo LCD 42" model DLP-42C1

thank you, next i will do some more test in the Q1,Q5 and IC1 area to be shure that the

component there are ok now it is time to go to bed thank you again