You are here

Sony KDL-37W5500 - Blinks 8 times (Audio Error)

6 posts / 0 new
Last post
mijatovic86 picture

Hello to everyone, i have a problem with this Sony LCD

Sony KDL-37W5500
Chassis EX2L
MAINBOARD: 1-878-942-22
Audio Amp: TAS5602
Sound System: CXA3785R-T6
main CPU: EMMA3 (under heat sink should be MB91F313APMC-GE1)
Power Supply: G4, 3H267W, PSC10270F

When i try to turn it on it clicks relay, blinks 1x Green Led, then it shuts down and blinks 8x Red Led.
Looking at service manual it should be an Audio Error. When i try to enter Self Diagnostic Menu it just wont light up the screen. I do the sequence "I+" "5" "V-" "Power" and it powers up regularly-fault 1xgreen 8x red, black screen.

From power supply i get all the voltages, except that 15V is 17.4V constant, but at the moment of powering it overshoots at 24V briefly.

Also i don't get D3.3V voltage. I have 12V on regulator BD9540EFV, but enable pins 3 and 12 are held too low on 1.6V, and it need at least 2.2V to enable output, so i dont have 3.3V, only 0,7V.
DVDD 3.3v is logic supply, so i dont get how CPU gets logic levels from ICs for error when there is no Logic Supply...

When i measure the power for audio amplifier TAS5602DCAR it should be 13V i suppose, but it gets 17.4V, from the CON1300 pins 4 and 5. It is ok for that IC, it works on voltages until 30V, but I worry if that does not affect some other processes.
Fault signal from audio amp TAS5602DCAR is on PIN19 and it is 3.3V that is HIGH and it suggests Normal Operation.
On sound system IC CXA3785R-T6 pin44 the VFAULT signal is LOW 0.7V, that is too normal operation.
But on audio amp pin18 TAS5602DCAR RESET is held in LOW and it does not go to HIGH to get out of the reset mode. That pin is controlled by main CPU signal X_SP_Mute.
On sound system IC CXA3785R-T6 pin43 X_Protect output is LOW 0.4V that means ERROR.
In datasheet it says X_PROTECTOUT outputs “L” when input voltage (SPxP/N) become under 3.0V.
That is on pins 61-62 and 63-64, and if I understand right it needs to have 3+ V DC to output High Normal signal?
Isnt that a bit too high to have on speakers? I measure 0V DC there, and 25mV AC.

Also i can not find anywhere schematics for PSU board PSC10270F(3H267W), i need it because i think that this 15V should be around 15V not 17,4V. I did find zener diode that i think acts as a stabilizator and it measures ok, but i would replace it if i knew the markings that can not be read.

All google stuff is from my posts so google wont help :)
What do you think can be the main problem and solution for this ?
I exclude replacing whole board

I have and Audio Amp IC coming soon to replace, but i think that wont help.

If anyone wants i can upload all pdfs that i have, ex2l SM, datasheets for audio ICs, datasheet for 3,3V regulator ect...

kolya61 picture

Szia !
Ниси журити ствари!
8 times blink red :D
Miga 8 razy

Üdv! Miki.


mijatovic86 picture

What does that help ?
i have topics on elektroda, badcaps, and :)
And still no one knows :)


mijatovic86 picture

I tried to over ride that X_protect Signal.
Attached 3.3V stdby signal to the resistor behind pin 43 x protect, and when i power on there is no more blinking, the green led i on, i responds to remote, it blinks when i change chanels and on power button on and off, it responds, but screen ins blank, to lamps are lit.
I have 24V on lamp board but looks like there is no enable signal to lit them up.
Problem is that there is no D3.3V on the board, on circuit BD9540EFV that should make 3.3 i get 12V on input, but 0.7 instead of 3.3 on output because enable signals are not over 2.2V, that is minimum enable threshold . It is 1.6V. :(


Kari picture

Hi Mijatovic,
"If anyone wants i can upload all pdfs that i have.."
You are very welcome by uploading all kind of your SMs and Schematics! :-)
Has for you some positive/side efect too because your weekly download limit will be higher...
Greetings - Kari


mijatovic86 picture

Well all those pdfs can be freely downloaded from internet and this site, so I can link them all here so they can be all on 1 place.

Sony KDL-37W5500