Toshiba 46RV530U - No Display. Has some power...

[ryanhull76]

Hello All.
I just joined, and I've read a ton of posts already about a similar model TV here on the forums already.

I've got this toshiba LCD HDTV, and a bad power supply.
No idea what happened to this. I got it from a girl's frat house.

Pulled the cover and checked for bad caps. I know a visual inspection isn't the end-all be-all, but nothing seems out of sorts.

There does seem to be a whining / high-pitched squeal coming from the HV side of the power supply at the end. (See pic with highlights.)

I've tested this board to this end only. I can get 12v from part A, and I do not get 24v from the inverter hookups.

I've replaced the Cap at C820, as when I tested it with an ohmmeter, it registered no resistance. (The new one tested fine with 4 ohms, then to almost 0, then starting "charging")

Also, the second fuse was popped. I've also replaced that part.

In reading the other post,
https://www.badcaps.net/forum/showpo...4&postcount=34

I see someone else had a problem with R850. Now I do not know how to test a fused resistor. I put leads on it and checked with all the ranges, but I get nothing. The little resistor only says it's 1.8 ohms, so I'm guessing it should at least something.

Regardless, it appears that something has broken and is not feeding power to the 24v side of the board. What that could be confuddles me, and my limited experience diagnosing electronics has become apparent.

Any help? I would like to learn how to test this resistor, but if something else seems obvious, please; by all means...

I'll post pics in the next post.

[ryanhull76]

Re: Toshiba 46RV530U - No Display. Has some power...

Picture of the Power Supply Board.
PE0564 Rev A

The squealing was coming from somewhere around R850. It's the little white resistor block at the bottom-left of the image. I guess it's also a fused resistor from reading the data spec sheet online.

Resistor reads...
RGDU5M-5E
1.8 OHMS J
NOBLE 98

Not sure if this resistor is bad, as I don't know how to test it.


Also, on a slightly different note. Is there a way to just test the LCD inverter board by supplying 24v DC to the pigtails that normally connect to it. The connectors for the 24v Inverter are the 2 white connectors at the top-left of the board.

There is also a 12v DC connector on the left of the board that goes to the video board. That board lights up when the set is turned on. Also, when the set is plugged in, you hear a click like a relay is clicked on. And when you press the power button, you hear another click.

but no video...

Thanks!

[retiredcaps]

Re: Toshiba 46RV530U - No Display. Has some power...

Now I do not know how to test a fused resistor. I put leads on it and checked with all the ranges, but I get nothing.

Post a picture of your multimeter.

If it is a manual range multimeter, set it to 200 ohms. Touch your probes together, it should be less than 1.0 ohms.

Now measure the resistance. If it shows "1" on the left hand side, it means the resistors value is > 201 ohms (out of range). If it is supposed to be a 1.8 ohm resistor, then it is bad.

[ryanhull76]

Re: Toshiba 46RV530U - No Display. Has some power...

Sorry, bad day for a picture of the multi-meter.
I did your test on the meter on the 200ohm setting, and it comes back with 1.3-1.5 on the display.

When testing the resistor, no matter what setting I put it on, it stays @ 1 on the left side. I'm suspecting this resistor is bad.

So question for everyone. I can order a new resistor and replace. Is there a way to bypass this resistor and continue testing the circuit?

Also, I found the service manual for this tv and am posting it here as an attachment. Enjoy! (And after following the service manual, I've determined that I need to replace this power supply board! Go figure. lol)

[tom66]

Re: Toshiba 46RV530U - No Display. Has some power...

Try on the 2k ohm range.

I have encountered those resistors failing on these types power supplies before. It's a common failure.

[ryanhull76]

Re: Toshiba 46RV530U - No Display. Has some power...

Looking at this project so far, I've seen a bad 480v cap, a blown fuse (upper right corner of board near the part #.) and now this fused resistor.

I'm starting to wonder what hit this TV, and what those frat girls did to it!

I found the whole board tested on ebay for $40 including shipping. I wonder if that's just the route to go and stop messing around diagnosing part by part.

If it did get hit by power surge, then I'm guessing I'm going to continue chasing bad parts across this thing.

Suggestions? Comments?

[tom66]

Re: Toshiba 46RV530U - No Display. Has some power...

Depends how much your time is worth to you.

I would just go for the $40 board if I were you.

[ryanhull76]

Re: Toshiba 46RV530U - No Display. Has some power...

I broke down and bought a used PS on ebay for $40 including the shipping. Set fired right up. Works and looks great.

I didn't figure it was worth the time to keep hunting down more bad parts, as without changing that fused resistor, who knows what else downstream was bad.

I thank everyone for the help, and I'll keep helping in the networking section, as that's what I actually know well.

-Ryan

[tom66]

Re: Toshiba 46RV530U - No Display. Has some power...

I broke down and bought a used PS on ebay for $40 including the shipping. Set fired right up. Works and looks great.

I didn't figure it was worth the time to keep hunting down more bad parts, as without changing that fused resistor, who knows what else downstream was bad.

I thank everyone for the help, and I'll keep helping in the networking section, as that's what I actually know well.

-Ryan

That's great, another TV saved from landfill. Enjoy your TV.

I have come to the same conclusion before and often after spending more than a few days chasing a fault around in my spare time, I'll just replace the entire board and be done with it. That being said, I do like a good challenge, so locating and fixing boards on the component level is very satisfying.

[stejones]

Re: Toshiba 46RV530U - No Display. Has some power...

Hi tom66 i have a PE0531 V28A000711C1 PSU for my toshiba tv and one of the resistors is dead do know of anywhere i can get these from many thanks

[tom66]

Re: Toshiba 46RV530U - No Display. Has some power...

Hi tom66 i have a PE0531 V28A000711C1 PSU for my toshiba tv and one of the resistors is dead do know of anywhere i can get these from many thanks

eBay, Rapid Online, Digi-Key, Mouser...

[selldoor]

Re: Toshiba 46RV530U - No Display. Has some power...

I believe Farnall has a trade counter in leeds.
Maplins probably ok for resistors

[stejones]

Re: Toshiba 46RV530U - No Display. Has some power...

eBay, Rapid Online, Digi-Key, Mouser...

you dont have a link to it do you pal i have been looking most of the day for these

[stejones]

Re: Toshiba 46RV530U - No Display. Has some power...

I believe Farnall has a trade counter in leeds.
Maplins probably ok for resistors

thanks pal been there today and they have nothing

[stejones]

Re: Toshiba 46RV530U - No Display. Has some power...

thats maplins i mean lol

[selldoor]

Re: Toshiba 46RV530U - No Display. Has some power...

What resistor are you looking for?

[stejones]

Re: Toshiba 46RV530U - No Display. Has some power...

all its says on the resistor is RGDU5M-5E J1.8 NOBLE 85 this is the board

[tom66]

Re: Toshiba 46RV530U - No Display. Has some power...

Does it have a colour code? Sounds like 1.8 ohms.

[stejones]

Re: Toshiba 46RV530U - No Display. Has some power...

what u mean by the colour code pal

[selldoor]

Re: Toshiba 46RV530U - No Display. Has some power...

Tom is thinking of a standard type resistor if you had posted a picture it would have helped
Does it look like this