KDL-40S5100 - No picture - Red LED blink x 2

[ahickman]

A co-worker brought me a Sony KDL-40S5100 that gives no picture, but responds to PWR button briefly. After about 1 second, the main relay releases (clicks) and the front LED responds by blinking twice. Looked at the service manual and it indicated that the issue was related to the PS board. I disconnected the external items from the PS and put a 3.3K resistor from STBY to GND and the PS comes up steady. Assume that the PS is getting a go ahead initially and then the feedback shuts the main A/C relay down. Looking at the schematics for the PS (they refer to it as IP1), I can see that there are several (AC DET, PWR ON, IC6300, etc.) points of potential failure, but am quite confused as to where to start in troubleshooting. A little overwhelmed and would appreciate a bit of guidance as always. I have attached the IP1 schemtic. BTW, I looked over the boards and saw no visual indications of faults (bad caps, fuses, burned IC's).

[Mt.Man]

Re: KDL-40S5100 - No picture - Red LED blink x 2

2X Protection Mode Blink Pattern
A 2X protection mode blink pattern can be activated due one of the following defects on the G2BE-Board or G2CE-Board.
• Loss of 12V (LVP)*
• Excessive 12V Level (OVP)*
• Excessive 24V Level (OVP)
*Low Voltage Protection (LVP)
*Over Voltage Protection (OVP)
A loss or excessive condition of the 12Vdc secondary voltage from the main power supply IC6501 will cause a 2X blink pattern on the Standby-LED. The 12Vdc can be checked at CN6201/pin 12.
If the measurement is 0V or rises above 12Vdc (approaches 15V) before the TV shut-off the G2BE-Board or G2CE-Board is defective.
IMPORTANT: Before replacing the G2BE-Board or G2CE-Board for the 12V LVP condition confirm the Power-ON voltage (3V) is present at CN6201/pin 1. If the voltage is missing confirm all connectors are secure. If so, replace the BM3-Board. If the 3V is present replace the G2BE-Board or G2BE-Board.
If approximately 12Vdc is present and remains below 12Vdc before shut-off then the BM3-Board is defective.
An excessive 24Vdc secondary voltage from the main power supply IC6501 will also cause a 2X blink pattern on the Standby-LED. The 24Vdc can be measured at CN6202/pin 12 before the TV shuts-off. If the voltage rises above the 24V level (approaches 27) before the TV shuts-off then the power supply is defective, replace the G2BE-Board or G2CE-board to fix the problem.

[ahickman]

Re: KDL-40S5100 - No picture - Red LED blink x 2

Trying to go through this circuit and understand how the standby voltage is developed initially. Assuming that RY6000 (main AC relay) is open before PWR button is pressed and the bridge rectifier does not see the 120 VAC. Looking at the STBY section, it gets power from T6200 secondary. T6200 looks to be fed by the DC rectified voltages coming from the bridge rectifier (D6000). Confused as to how 3.3V STBY would be derived at the get-go if the AC relay (RY6000) is open to begin with. Help???

[ahickman]

Re: KDL-40S5100 - No picture - Red LED blink x 2

Mt. Man, thanks for the insight. Exactly what I was hoping for in terms of getting me started. I posted above at the same time you did so.

[ahickman]

Re: KDL-40S5100 - No picture - Red LED blink x 2

Just got home and put my DVM on each of the following pins. You referenced CN6201 pins, but I believe the equivalent connector on the IP1 board (KDL-40S5100) is CN6150 and the pins are 11, 12 & 13 for +12V and pin 3 for STBY_3.3V.

STBY_3.3V is present (reads 3.38V) both before PWR button is pressed and after being pressed.

Pins 11, 12 and 13 show 0.0V before PWR button is pressed and 0.36V briefly after PWR button is pressed.

I am going to check the Schottky diodes (D6150 and D6151) for shorts.

Suggestions?

[RON_CET]

Re: KDL-40S5100 - No picture - Red LED blink x 2

on your last post#5 you didn't mention if the Power-ON voltage (3V) is present at pin 1 of connector CN6150 change from a low to high state when power button is pressed to turn on then off? If yes next do you hear relay RY6000 energize and then de-energize as power switch push on/off? NOTE... RY6000 relay is only going to function when it recieves the power_on command via Q6404,PH6300,Q6302,Q6300

[ahickman]

Re: KDL-40S5100 - No picture - Red LED blink x 2

Using a DVM, I see 3.38 - 3.36 VDC on PWR_ON before and after power up. Never see it drop, but don't have a scope at home to look at it. When PWR_ON is pressed, RY6000 energizes for about 1.5 - 2 seconds and then releases.

[ahickman]

Re: KDL-40S5100 - No picture - Red LED blink x 2

Is R6329 supposed to act as a pull-up resistor of sorts when IC6501 is charged up? I don't ever see pin 8 on IC6501 give anything but 0.0V. Kinda shooting in the wind here I reckon!

[RON_CET]

Re: KDL-40S5100 - No picture - Red LED blink x 2

pin 8 of IC6501 gets it source voltage via R6329 but make sure your ground is correct i use the Negative side of C6501 or EY6529 gnd stake if at that time you still have 0 volts your next step make sure R6329 is not open or no shorts on that line.

[ahickman]

Re: KDL-40S5100 - No picture - Red LED blink x 2

Out of time and pressed to get the TV back in the hands of the owner. ShopJimmy to the rescue. A new PS and the set works perfectly. When I have time, I am going to scroll over the old PS and look for the failure. Thanks to everyone for their suggestions on this one.

[ahickman]

Re: KDL-40S5100 - No picture - Red LED blink x 2

Well, this set failed again with the exact same symptoms. 2 x's red LED blink. Buying another board would be senseless, so I am compelled to find the problem. Any input would be greatly appreciated as always. I really don't have the best grasp on how the PS's function in terms of PFC and OVP IC's. Here is what I see when I have a 1 K ohm across PWR_ON and STBY (3.3 VDC):

1. Q6100's drain reads 165 in standby mode (resistor off) and 394 when PWR_ON is high.
2. Pin 1 of IC6102 reads 2.18 VDC when PWR_ON is high.
3. Pin 8 of IC6501 reads 15.81 VDC when PWR_ON is high.

[ahickman]

Re: KDL-40S5100 - No picture - Red LED blink x 2

Pictures of the front/back of PS.

[budm]

Re: KDL-40S5100 - No picture - Red LED blink x 2

OK, you only post one of two page of the power supply, I do not see the 24v power supply section.
There are MANY detection circuits in this TV.
This how the circuit in this page works: I hope you can follow it, print out the diagram on big piece of paper will help. It is not that bad.
1) TV is plugged in but the power switch is not activated yet. The relay is open, the power to bridge rectifier D600 through the resistor R6016 which is connected across the relay contact. The output of the rectifier is filtered by the main filter cap C6501, it will have about 160~170VDC (MAIN B+) on it.
2) The MAIN B+ is used for running the always-on STBY_3.3V power supply (IC 6200, it drive the power transformer T6200), which is used for running the main board micro controller.
3) The transformer winding of T6200 pin 9 & 10 is for generating the 3.3VDC.
4) The transformer winding of T6200 pin 3 & 4 is for generating the VCC pin4 of the IC 6200.
5) The transformer winding of T6200 pin 1 & 2 is for generating B+ for feeding the switch Q6300 and for the IC 6300 (AC detect, PFC detect, PFC_OVP, .
6) When >3V is applied to POWER_ON pin, this voltage is fed to R6421 in series with R6410, the output of R6410 will turn on Q6404, which will then turn on the LED inside the Opto PH6300, the Photo transistor will also turn on. This will turn Q6302 which cause the switch Q6300 to turn on and supply the voltage (SWITCHED B+) to turn on the Main relay (contact is now closed), this SWITCHED B+ is now will feed the PFC IC 6501 which will cause the DC voltage on the main DC filter cap C6501 to rise up to 380~400VDC. The SWITCHED B+ is also feed SMPS IC 6102 which drive the MOSFET Q6100, Q6101 which drive the power transformer that produce 12v and the 13v.
7) If the 12v output goes too high, this will bias on Zener Diode D6400 this will turn on the latching circuits consist of Q6402, Q6403. This will route the POWER_ON signal at the junction of R6421, R6410 to ground that will turn off Q6404 that will turn off the SWITCH B+ that is used for the PFC and the SMPS (12V/13V) ICs.
8) IC 6300 does the AC present detection, PFC DETECT (not used), PFC OVP (OVER VOLTAGE). If the PFC boosted voltage goes to high (detection at pin 2) the PFC_OVP OUT pin 4 will go low which will turn off Q6302 which in turn will turn off switch Q6300 for the SWITCHED B+ , again turn off the PFC and the SMPS (12V/13V). Notes: I am not sure the ACDETECT OUT at pin 7 should be high or low when AC is detected since I do not have the 2nd page of the power supply circuit.

As you can see, we can defeat the detection circuit to find out what causes the shutdown. The first place to look will be the POWER ON signal pin, we need to see if it is still there when the TV goes in to shutdown mode.
I need to see the second page of the power supply circuits.

[ahickman]

Re: KDL-40S5100 - No picture - Red LED blink x 2

Here is the service manual I found online.

[budm]

Re: KDL-40S5100 - No picture - Red LED blink x 2

So look at the Power ON pin to see if it is still there when the relay click off. Look at the 12v LINE to see if it went way over 12v, you may have to use peak hold function to catch that.
By the way, where can I download the whole service manual so I can read up on the error codes and function of the TV?

[man9cob]

Re: KDL-40S5100 - No picture - Red LED blink x 2

Hi I am Mani from India. Got to know this forum via search engine. Very nice to see the details. Thank you all. I have one issue in my Sony Bravia 40S504 Power Supply board 1-878-598- 11. The link for the schematic is below.


The problem here is even though when we give power on command, the main relay is not getting closed. If i forcefully close, the tv is turning on and working fine. I suspect its having start up problem. probably with Relay driver. Is there any helping hand to fix this issue. i do not want to replace the board and want to fix this by changing the component. Any suggestion is welcome. Looking forward for the support.

Thanks and Regards
Mani

[budm]

Re: KDL-40S5100 - No picture - Red LED blink x 2

@MAN9COB, so your TV is model 40504??, the service manual in the link is for 40SL150, if that is power supply section matches your TV then you need to check the DC Voltage at test point 1 (use Secondary ground ref), then the DC Voltages on 2, 3, and 4 using Primary ground ref. report the readings.
You should start a new thread for the correct model you are working on.

[man9cob]

Re: KDL-40S5100 - No picture - Red LED blink x 2

Hi Budm, how are you? thanks for your quick reply. Yes my PS board is holding same schematic. Unfortunately i am outstation for this week. i will do check and let you know the voltages by this weekend to get further help from you. mean time if you suspect or want some more points please post, i can do everything together. i am very much grateful to you for supporting me. sorry for the delay in response. mean time i have connected external switch to short relay contact manually and release the start up problem. once the TV is ON i will open the external switch again. the sequence is Power On - External Switch ON - External Switch OFF, once manually short the contact, immediately the relay getting 15.46Vdc at the coil, so relay getting closed always. if you feel any logic behind please share with me.

Thanks and Regards
Mani

[budm]

Re: KDL-40S5100 - No picture - Red LED blink x 2

OK, I will wait for the voltage reading at those test points, it will tell me if those transistors are getting the correct signal or not.