Toshiba 40rv525u power led flashing / will not come on

[s40ward]

Hello all,
I have a Toshiba 40rv525u that recently stopped working. The power LED will begin blinking immediately after the TV is plugged in. I don't believe it's blinking any kind of diagnostic code, as there is no pattern, it just blinks every couple seconds repeatedly. I have tried replacing the power board and the main board, but this did not solve my problem. I believe the problem is keeping the TV from it's normal start-up process, as there is absolutely no light from the panel or sound.

I have attached a picture of my workbench with the TV open. I have a benchtop digital multimeter, oscilloscope, function generator, and an ESR meter. Believe it or not, even with all this equipment I have a limited electronics knowledge. So I have come here for assistance with diagnosing this TV. I will be quick to reply, and follow all directions and recommendations.

All help is greatly appreciated and will be met with gratitude. Thank you.

[budm]

Re: Toshiba 40rv525u power led flashing / will not come on

Most Toshiba TV will have blinking LED during start up, it is doing self test mode, it can last as long as 30 seconds, then after 30 seconds if the TV will not start up then you will have to count the blinks to figure out the code.
You may want to look through these threads:
https://www.badcaps.net/forum/search...archid=3020054

[s40ward]

Re: Toshiba 40rv525u power led flashing / will not come on

I see. I have confirmed after waiting the TV will not turn on with the remote or power on button. I will happily test voltages, provide high-res pictures, or anything else I can to help.

Also, I have read pretty much everything google returns regarding this model number and problem, including on badcaps.net. Most threads end before a resolution, or are fixed by something I've already tried. I also read your LCD TV & Monitor troubleshooting guides. I'll continue reading until someone engages me with testing the TV.

[tom66]

Re: Toshiba 40rv525u power led flashing / will not come on

The first step is to verify all the power board voltages are good during the self test. Can you do that, do you need help in doing so?

[s40ward]

Re: Toshiba 40rv525u power led flashing / will not come on

Yes, I can check voltages. Please let me know if my answers are deficient or if I skipped any of the important voltages. I truly appreciate the attention on this. I attached a diagram of my power supply connectors to be sure we're on the same page.

P803 pins 1-5 are all 24v, drop to 7v over about 1 second, then back up to 24v repeatedly

P802 pins 8 and 9 are ~11v, drop to ~2v over about 1 second, then back up to ~11v

P802 pins 10 and 11 fluctuate between 1v-5v.

P802 pin 12 jumps between 50mv to 2v.

[budm]

Re: Toshiba 40rv525u power led flashing / will not come on

Can you upload the service manual?

[s40ward]

Re: Toshiba 40rv525u power led flashing / will not come on

Sure! I followed the troubleshooting guide but it pointed to the power supply or main board, both of which I've purchased replacements for and neither fixed it. There's always the case of a bad replacement..but I figured it was time to call in some help. I'll be available all day to work with whomever wants to help! Thanks.

P.S. I also uploaded this on the other thread here asking for this service manual. Found it on scribd after a LONG search.

[s40ward]

Re: Toshiba 40rv525u power led flashing / will not come on

I thought it might help if I uploaded some additional pictures and a video.
The video is of the power LED just so that can be seen as well.
http://img818.*************/img818/4681/qlofmubsnnridolyttvaax.mp4

[s40ward]

Re: Toshiba 40rv525u power led flashing / will not come on

I found another service manual I'll upload here, but it keeps giving me ZEUS errors. I've tried this several times before and never had success. The ZEUS engine is a PITA. I believe this has the information needed. Perhaps you guys have experience with this?

edit: file too large to upload directly to the forum. I uploaded it to a file sharing service here.

http://www.filedropper.com/toshiba40...vicemanualzeus

[budm]

Re: Toshiba 40rv525u power led flashing / will not come on

"P802 pin 12 jumps between 50mv to 2v." Pin 10~12 of P802 is the STBY 5V, it should be steady 5VDC.
So disconnect P802 to check and see if the 5V will be steady.

[s40ward]

Re: Toshiba 40rv525u power led flashing / will not come on

After disconnecting P802 and reading pins 10-12 they all show a steady 5.0658v. Thank you for your response. Does this indicate a faulty main board?

[budm]

Re: Toshiba 40rv525u power led flashing / will not come on

It is either the main board is drawing too much power, or the power supply is weak due to bad cap. Can you see any kind of power supply rating on the board, it will say something like 5V 1A, 24V 6A, etc. What we can do is to use a resistor as the load and see if the power supply will stay at 5V,

[budm]

Re: Toshiba 40rv525u power led flashing / will not come on

You can use 4.7 Ohm 10 watts as the load, that will draw about 1A to see if it can handle it or not.

[s40ward]

Re: Toshiba 40rv525u power led flashing / will not come on

I checked the power and main boards and I do not see anything quite like that. I'll start looking for a resistor close to that rating. Most of what I have here seems to be higher resistance.

[budm]

Re: Toshiba 40rv525u power led flashing / will not come on

You can parallel or series the resistots to get close to 5 ohms, does not have to be exact.

[s40ward]

Re: Toshiba 40rv525u power led flashing / will not come on

Well I went through all the resistors I have on hand, and the closest I can get is to use 22x 220 ohm resistors and 2x 250 ohm resistors for a parallel resistance of ~9.25 ohms (if my math is right). So....I guess I'll be making a trip to the store tomorrow.

I did however notice this forgotten piece of equipment. Can it be used? (pic attached) If not I'll bump the post when I have the proper resistor.

[budm]

Re: Toshiba 40rv525u power led flashing / will not come on

By the way, are you able to count the blinking pattern? If it is the power supply problem, you can try changing those two caps.

[s40ward]

Re: Toshiba 40rv525u power led flashing / will not come on

I purchased a 5ohm 10watt resistor today and tested pins 10-12 and (if I took the reading correctly) read a steady 5v. As far as the blinking pattern, I have not been able to recognize a pattern whatsoever. It blinks at a constant rate. I tried waiting 30 seconds, but nothing changes.

[budm]

Re: Toshiba 40rv525u power led flashing / will not come on

So the power supply can handle 1A with no problem, that means the main board is drawing so much in standby mode that causes the 5V to be going up and down. Without the diagram it will be difficult to troubleshoot.

[s40ward]

Re: Toshiba 40rv525u power led flashing / will not come on

I've tried for months to open this schematic, and I finally succeeded today!

I've attached an image that shows you what the schematic looks like in the Toshiba ZEUS program. To open it I had to install a VMware virtual machine with Windows XP, IE6, ZEUS 2.0, and DWF Viewer 6.0 w/ zeus patch. IE took some tweaking as well. If you're willing to do all this I'll be more than happy to get you all the software you need, but if you'd rather direct me I can take screenshots of specific areas of the schematic. If that won't work well enough, I can go through the process of screenshotting about 1/6 of each image at a time and piecing together the individual images for the entire schematic (about 20 images total). The problem is the schematics are .DWF files, and there's so much information I can't just zoom out and take a screenshot or the values become distorted. Let me know what you need, I will provide it! Thanks again for the effort.