Toshiba 42HL196 LCD: Red blinking light

[itshockedme]

I'm looking for some assistance troubleshooting the power supply board. I've done research and already replaced the most common components suggested by others for the TV not turning on with three blinking lights. After replacing Q820, Q860 and Q880, the TV was making a clicking noise and would not power on. Then, after replacing C888-C890 and D884A, the clicking noise returned when pushing the power button. So I'm back to three lights blinking and no powering up. I have the factory repair manual for reference and can give meter readings if someone can assist me in testing some components and/or any other suggestions. Thanks.

[itshockedme]

Re: Toshiba 42HL196 LCD: Red blinking light

Service manual

[budm]

Re: Toshiba 42HL196 LCD: Red blinking light

Can you please tell me what pages those components you had replaced are in so I can see what their functions are.
Right now the 5VSTBY is working, but I need to know if the PFC is working. Check the DC voltage on fuse F820 when the TV is plugged in but the power switch is not activated yet, then when the power switch is activated.
Since you will working in the Primary side, make sure you do not touch any part of the TV with your body. You will be using the Negative leg of C820 (Large DC filter cap) as the reference ground point of the primary circuits for you meter black probe.

[RON_CET]

Re: Toshiba 42HL196 LCD: Red blinking light

Usually replacing Q820 correct 90% of this problem with the 3 blink power led attached is the smarttech guide for additional troubleshooting help right now my opinion is your having boot issues and have seen the SEIN board cause this 3 blink issue

[itshockedme]

Re: Toshiba 42HL196 LCD: Red blinking light

Can you please tell me what pages those components you had replaced are in so I can see what their functions are.
Right now the 5VSTBY is working, but I need to know if the PFC is working. Check the DC voltage on fuse F820 when the TV is plugged in but the power switch is not activated yet, then when the power switch is activated.
Since you will working in the Primary side, make sure you do not touch any part of the TV with your body. You will be using the Negative leg of C820 (Large DC filter cap) as the reference ground point of the primary circuits for you meter black probe.

Q820 can be found on page 19 (from the toshiba manual).
Q880, C888, C889, C890 and D884A can be found on page 21.
Q860 can be found on page 22.
I will be checking the DC voltage on fuse F820 right now.

[itshockedme]

Re: Toshiba 42HL196 LCD: Red blinking light

Usually replacing Q820 correct 90% of this problem with the 3 blink power led attached is the smarttech guide for additional troubleshooting help right now my opinion is your having boot issues and have seen the SEIN board cause this 3 blink issue

Thank you for the update on the troubleshooting info. It's very helpful.

[budm]

Re: Toshiba 42HL196 LCD: Red blinking light

The info Ron provided looks like it may be the correct place to look since he has worked on this model before.

[itshockedme]

Re: Toshiba 42HL196 LCD: Red blinking light

Thanks budm, I really appreciate you taking the time to assist me. I feel like I've been up against a brick wall with this one. The DC voltage on fuse F820 when the TV was plugged in (power switch not activated) was fluctuating from 165.9V and 154.0V when clicking. Once the TV was plugged in, the relay was cycling (two clicks) consistently. The DC voltage on fuse F820 when plugged in and power switch activated was fluctuating from 167.0V and 153.6 when clicking. Are these readings within range? Any ideas on where to go from here?

[budm]

Re: Toshiba 42HL196 LCD: Red blinking light

I will have to study the circuits more and try to understand the info that Ron provided to see if it is relating to what you are seeing right now.

[itshockedme]

Re: Toshiba 42HL196 LCD: Red blinking light

Using the updated information posted by RON_CET (from the troubleshooting flow chart on page 4), I am getting a 3.28V reading on PIN 7 of CN49A. For some reason, I am not getting any voltage reading on PIN 5 of P812A.

[rlforget]

Re: Toshiba 42HL196 LCD: Red blinking light

Hi ISM,

I had exactly the same issue as you described and found the solution on the first try with only the internet as my guide.

On another forum, more than one person fixed this by replacing the STRW 6765 switch mode regulator on the main power supply board. Apparently very common on this set. If you haven't done this yet...

Three bucks on ebay and an hour and a half labor. Worked for me!

Good luck, Rick

[itshockedme]

Re: Toshiba 42HL196 LCD: Red blinking light

Hi ISM,

I had exactly the same issue as you described and found the solution on the first try with only the internet as my guide.

On another forum, more than one person fixed this by replacing the STRW 6765 switch mode regulator on the main power supply board. Apparently very common on this set. If you haven't done this yet...

Three bucks on ebay and an hour and a half labor. Worked for me!

Good luck, Rick

Thanks for input that is the same place I started also but no luck only clicking sound after replacing Q880 which is IC STRW6765

[itshockedme]

Re: Toshiba 42HL196 LCD: Red blinking light

uuhhggg..im stuck can anyone help me troubleshoot this power supply board??? Please I have meter an schematics and can take pics or whaterever is needed. Im know its not seine board because it powered on a couple times for a few seconds.

[tom66]

Re: Toshiba 42HL196 LCD: Red blinking light

So, have you got good supply voltages from the power supply? If so, I would not suspect the power supply. (I have been mislead by those flowcharts enough to take them with a pinch of salt.)

[ben7]

Re: Toshiba 42HL196 LCD: Red blinking light

uuhhggg..im stuck can anyone help me troubleshoot this power supply board??? Please I have meter an schematics and can take pics or whaterever is needed. Im know its not seine board because it powered on a couple times for a few seconds.

You say it powered on a few times - I would suspect that there is an issue with the backlight inverter(s).

Other than that, make sure you replaced the startup cap in the power supply too!

[itshockedme]

Re: Toshiba 42HL196 LCD: Red blinking light

So, have you got good supply voltages from the power supply? If so, I would not suspect the power supply. (I have been mislead by those flowcharts enough to take them with a pinch of salt.)

Can you give me some tips on how to test the voltages from the power supply? I just want to make sure that I'm in the right area.

[itshockedme]

Re: Toshiba 42HL196 LCD: Red blinking light

You say it powered on a few times - I would suspect that there is an issue with the backlight inverter(s).

Other than that, make sure you replaced the startup cap in the power supply too!

Is the large DC filter cap (C820) the startup cap in the power supply?

[itshockedme]

Re: Toshiba 42HL196 LCD: Red blinking light

Help!!

[itshockedme]

Re: Toshiba 42HL196 LCD: Red blinking light

With my meters negative lead on a ground where circuit board bolts to tv. And positive lead on top a heatsink im getting voltage reading..Does this mean i have a short?