Toshiba 42RV530U Won't Startup

[rblack711]

Trying to resurrect a Toshiba 42RV530U, and was hoping I could get some clues from you guys. Blinking yellow led on the front of the TV and a relay click - otherwise no life.

Power supply has 122VAC at the bridge input and 168vdc at the output. The large bulk capacitor (C820) has 165vdc when the TV is in standby and 391vdc when the TV is turned on.

Here's the voltage I measured at the power supply connectors when the TV is plugged in:
Pin V
5V1 5.0
12V 11.8
POWER_PRO 3.0

And when the power button is pushed:
POWER_TV 3.3
POWER_DB 5.0
AC_DETECT 3.6
18V AUDIO 9.0
24V 0

I'm new to TV repair, but everything seems to be normal except for lack of 24v. I unmated the 24v connectors from the power supply to see if the inverter boards might be causing the 24v circuit to shutdown, but still 0 volts at the pins. Fuses are good on the board. Any ideas how to isolate the problem? I don't have a schematic to work with unfortunately and can't find one on the internet so far.

[dskall]

Re: Toshiba 42RV530U Won't Startup

What is voltage on POWER_TV in standby?

[R_J]

Re: Toshiba 42RV530U Won't Startup

Is the model of the power supply PE0546?
What happens to the 12v when the power button is pressed? If you have 12v you should also have 24v

These power supplies have fuses in the secondary, also check for poor solder connections on the transformer T860

[rblack711]

Re: Toshiba 42RV530U Won't Startup

What is voltage on POWER_TV in standby?

Is the model of the power supply PE0546?
What happens to the 12v when the power button is pressed? If you have 12v you should also have 24v

These power supplies have fuses in the secondary, also check for poor solder connections on the transformer T860

This is stranger than I first thought. When the TV is plugged in, POWER_TV=3.3v (without pressing the ON button), then after about a minute it goes to 0v.

The 12V pins are at 11.8 volts, but then when POWER_TV goes to 0v, the voltage very slowly decreases and after about 10 minutes or so, goes to 0. When the power button is pressed, 12V returns to 11.8v and remains steady until either I press the power button again, or the TV automatically turns itself off (POWER_TV=0), which happens in about a minute. The 12V then again gradually decays to 0v over about a 10 minute period. There are also 2 pins labeled 12VLCD, but they are always at 0v. The only pins that remain constant at all times are 5V1 (5v) and POWER_PRO (3v).

There are 2 fuses in the secondary, and I had checked those previously, but I'll recheck them. I also had closely inspected all solder joints with magnification previously but I'll focus on T860. This is a PE0546A board.

[rblack711]

Re: Toshiba 42RV530U Won't Startup

The solder joints look good on T860. Secondary fuses F870 and F871 are good as well.

[nomoresonys]

Re: Toshiba 42RV530U Won't Startup

Not sure, maybe check D870, D871, D872.

[dskall]

Re: Toshiba 42RV530U Won't Startup

Doesn't look like power_tv is your control from mainboard. Not familiar with these markings. It maybe just going to standby after a short time.
Can we get pictures of your connector markings?

[R_J]

Re: Toshiba 42RV530U Won't Startup

You didn't answer my question about the 24 volts so I will assume it is there so your problem could be on the inverter or a fault with the backlight ccfl's

[rblack711]

Re: Toshiba 42RV530U Won't Startup

You didn't answer my question about the 24 volts so I will assume it is there so your problem could be on the inverter or a fault with the backlight ccfl's

What's the question for 24v? It is 0v in standby and when power button is pressed, and when invertor connectors are disconnected. No 24v at any time.

[R_J]

Re: Toshiba 42RV530U Won't Startup

So you don't have 24 volts but you do have 12 volts, both are supplied by the same transformer.
Here are the two versions of the schematic for the PE0546

[lotas]

Re: Toshiba 42RV530U Won't Startup

Toshiba Power Supply PE0546A

[rblack711]

Re: Toshiba 42RV530U Won't Startup

So you don't have 24 volts but you do have 12 volts, both are supplied by the same transformer.

Ha. So, when I was pulling the cables off to take pictures of the connectors, I discovered a pin named "24v" that was hiding behind the wire bundle. So, my mistake, I do have 24v at that pin, in fact, 24.5v. I have it when I first plug in the TV or when I press the power button to turn the TV on. And it acts in the same manner as the 12v pins in that it slowly decays to 0v in about 10 minutes when power is turned off (or automatically shutoff by the TV). The pins that I never have 24v on are the ones going to the inverters (even if the inverters are disconnected) - those are ones I have been reporting 0v. Sorry for the confusion.
Here are pics of the power board pins.

[rblack711]

Re: Toshiba 42RV530U Won't Startup

Doesn't look like power_tv is your control from mainboard. Not familiar with these markings. It maybe just going to standby after a short time.
Can we get pictures of your connector markings?

You could be right - there is a pin called "Pow_Sig", but I never see voltage on it. See pics.

[R_J]

Re: Toshiba 42RV530U Won't Startup

The +24v for the inverter is controlled by the mosfet Q8880, This is turned on by the POWER_SIG (needs to he high +3~5v) There is however a protection circuit that may shut this signal down

Do you have 12VLCD on P810? if not try disconnecting the lvds cable to the t-con board and see if the 24VINV comes up

[rblack711]

Re: Toshiba 42RV530U Won't Startup

The +24v for the inverter is controlled by the mosfet Q8880, This is turned on by the POWER_SIG (needs to he high +3~5v) There is however a protection circuit that may shut this signal down

Do you have 12VLCD on P810? if not try disconnecting the lvds cable to the t-con board and see if the 24VINV comes up

No voltage at 12VLCD. I disconnected the t-con cable and still no voltage at 24INV.

I wonder if there is a problem with the main board then if it is supposed to be sending the POWER_SIG signal? I still have the blinking yellow led happening at the front of the TV, so maybe it isn't "initializing" correctly (if that's the correct term). It's definitely sending the POWER_TV signal but not sure what that does (beside turn on the 24v/12v transformer).

[rblack711]

Re: Toshiba 42RV530U Won't Startup

Toshiba Power Supply PE0546A

Thanks for uploading that - I couldn't find it anywhere. I have found the service manual but it is in some form that requires an abstract software called Zeus that I can't get to work.

[R_J]

Re: Toshiba 42RV530U Won't Startup

Thanks for uploading that - I couldn't find it anywhere. I have found the service manual but it is in some form that requires an abstract software called Zeus that I can't get to work.

That Dr. zeus doftware is what Toshiba used for a while, I always hated it, The manual is available in pdf.

[rblack711]

Re: Toshiba 42RV530U Won't Startup

That Dr. zeus doftware is what Toshiba used for a while, I always hated it, The manual is available in pdf.

Thanks RJ, I found that one, but it's more like just a regular user's manual. There is a version (I think it is 2.01 or something like that) that is about 75 pages and has the all the detailed technical data and schematics in it. I cannot find a pdf of it so far.

Would you agree that it appears the power supply is functioning normally on this TV or is there anything else to test? There is an SD slot on the main board for updating firmware - maybe it somehow became corrupted. This manual indicates that yellow blinking LED means Seine is booting, whatever Seine is. Do you think re-flashing the f/w might be worth a try?

[R_J]

Re: Toshiba 42RV530U Won't Startup

Seine, is basically the main board

[rblack711]

Re: Toshiba 42RV530U Won't Startup

Seine, is basically the main board

This is going to drive me in-Seine

So, I decided that I want to try reloading the firmware. Called Toshiba, which is now handled by Dynabook, to get the latest f/w for this set. Recording tells me that to go to website if my TV is older than 2015. Go to website, enter model number - no software available. WTF, this TV isn't from 1985 - it's a 2008 (most of my socks are older than that and they probably have 10 years left on them).

My search for the f/w is going as well as my search for the service manual. Does anyone happen to know where I might find firmware for a prehistoric Toshiba model 42RV530U TV?