Sanyo DP46849 46" LCD - Does not power up.

[tom66]

Re: Sanyo DP46849 46" LCD - Does not power up.

Some? Grab them ALL.

Will if I can. Upstairs, 3rd floor, there's a whole room (classroom sized) dedicated to condemned equipment. Failed safety test or doesn't work... some of it's just obsolete and works fine! And you know what? I can't touch a single thing. Because they're worried if they give away or sell these items, they're liable for any injury as a result of attempted repair or failure of the device. Seriously... I told them I'd sign a million disclaimers but they wouldn't have it.

[Deebeaux]

Re: Sanyo DP46849 46" LCD - Does not power up.

I deal with this sort of thing all the time. It's sad. There's tons of equipment in all sorts of state, federal, school system owned organizations that just rots because some lawyer could take them to the cleaners if someone uses the equipment and gets injured through their own negligence or stupidity.

Will if I can. Upstairs, 3rd floor, there's a whole room (classroom sized) dedicated to condemned equipment. Failed safety test or doesn't work... some of it's just obsolete and works fine! And you know what? I can't touch a single thing. Because they're worried if they give away or sell these items, they're liable for any injury as a result of attempted repair or failure of the device. Seriously... I told them I'd sign a million disclaimers but they wouldn't have it.

[Deebeaux]

Re: Sanyo DP46849 46" LCD - Does not power up.

Replaced IC. What should I do next? Plug it in and check?

[tom66]

Re: Sanyo DP46849 46" LCD - Does not power up.

If you have a 25W or 40W (120V) lightbulb available, remove the fuse and touch it across it, or clip it to the terminals on the bulb. If there's a fault in the standby circuit, the bulb will stay lit, but if everything's fine, the bulb will flash then go out, and you should see a standby LED. When that is successful remove the bulb and attempt to power on TV normally (the TV will not start with a bulb in series but it will usually run in standby mode.)

[Deebeaux]

Re: Sanyo DP46849 46" LCD - Does not power up.

What if I don't have such light bulb available? I guess I can go buy a light bulb and a socket if there's no alternative. Fuse is soldered on so not sure how to attach bulb to board after it's removed, could solder bulb socket leads to board?

If you have a 25W or 40W (120V) lightbulb available, remove the fuse and touch it across it, or clip it to the terminals on the bulb. If there's a fault in the standby circuit, the bulb will stay lit, but if everything's fine, the bulb will flash then go out, and you should see a standby LED. When that is successful remove the bulb and attempt to power on TV normally (the TV will not start with a bulb in series but it will usually run in standby mode.)

[tom66]

Re: Sanyo DP46849 46" LCD - Does not power up.

Then power it up without the bulb. You risk potential damage to the IC you replaced, but in most cases nothing will happen.

[Deebeaux]

Re: Sanyo DP46849 46" LCD - Does not power up.

If there's one thing I've learned, I don't fit in "most cases" statements. I'll pickup a socket and bulb this week and give it a go. Might as well add this tool to the arsenal since I seem to be tinkering with more TVs/Monitors these days. Just to clarify I'd wire the bulb in place of the fuse (removing the fuse) and looking for flash or steady on? And we are talking about the T6.3AH/250V fuse that does read line voltage (120VAC) when the TV is plugged in?

Thanks!

Then power it up without the bulb. You risk potential damage to the IC you replaced, but in most cases nothing will happen.

[tom66]

Re: Sanyo DP46849 46" LCD - Does not power up.

Yes, that fuse but you can also wire it in series with the live wire, or something like that. Get a 100W bulb and 25W bulb, which will cover most use cases.

[retiredcaps]

Re: Sanyo DP46849 46" LCD - Does not power up.

I'll pickup a socket and bulb this week and give it a go.

See

https://www.badcaps.net/forum/showpo...07&postcount=7

[Deebeaux]

Re: Sanyo DP46849 46" LCD - Does not power up.

Alright, built the rig, tested with a 40W bulb (that's what I had around the house) ... I was also able to get my hands on a 100W bulb for future needs. Enclosed picture of load-rig just for fun. Never mind the cracked bulb base, came that way out of the box, planning on exchanging next time I venture out of the house. Will open package and check this time. Argh.

The bulb flashed quickly and went out (40W) but no standby/pilot light. I did check for power between the 5VSTB and GND pin on the power board and I do get 5V now, just not sure where to go from here. I guess it's possible we've got a problem on the main board. This also came out of a near lightning strike house. Oh, and if it matters, I tried the procedure with everything plugged in to the power board and with nothing plugged in. May not have been the best method but I plugged everything in after reinstalling the board and transporting the TV to my home workshop.

I didn't want to just hit power without a pilot light because I've done that in the past on electronics before and let out the magic smoke in doing so.

Any advice is, as always, much appreciated.

[tom66]

Re: Sanyo DP46849 46" LCD - Does not power up.

Neat!

What I would do is power up the TV without the bulb. Some TVs do a self-test of the power supply when powering up, if that fails then the standby light won't light or will blink an error code.

[Deebeaux]

Re: Sanyo DP46849 46" LCD - Does not power up.

So plug it into the wall and hit the power button? I do not get standby light even without the bulb. Guess I should have mentioned that.

Should I plug everything back into the supply board or only certain things? Like maybe not the HV stuff?

Just being cautious because I had a similar situation (before I knew about the lightbulb trick) with a TV that I repaired the power board, did not have a pilot light, and when I hit the power button a lightning bolt shot out of some surface mount components rendering it not worth fixing. Had to replace entire board.

Dave

Neat!

What I would do is power up the TV without the bulb. Some TVs do a self-test of the power supply when powering up, if that fails then the standby light won't light or will blink an error code.

[tom66]

Re: Sanyo DP46849 46" LCD - Does not power up.

Connect everything as the TV should be connected. The lightbulb trick shows there is no short so you should be safe.

[Deebeaux]

Re: Sanyo DP46849 46" LCD - Does not power up.

There's two connectors labeled High Voltage on the output of the board. They are seemingly identical. I assume they're for the CCFL back lights. Does it matter which connector goes in which socket? I took a picture of it before I disconnected it, but the markings are in such a way they're not visible unless they're unplugged. Totally may fault. If they do matter, I can take the rest of the back of the set off and see if I can figure out which one is which.

Connect everything as the TV should be connected. The lightbulb trick shows there is no short so you should be safe.

[tom66]

Re: Sanyo DP46849 46" LCD - Does not power up.

It doesn't matter, though usually it's difficult to get them in the "wrong" way.

[Deebeaux]

Re: Sanyo DP46849 46" LCD - Does not power up.

I didn't think it mattered, but I figured it was worth a shot to ask. I wasn't concerned about getting the connector into the socket incorrectly. There's two connectors and two sockets. Was curious if there's like Socket A and Connector A vs. Socket B and Connector B. Didn't want to melt down something if I A->B'd something.

It doesn't matter, though usually it's difficult to get them in the "wrong" way.

[Deebeaux]

Re: Sanyo DP46849 46" LCD - Does not power up.

Magnificent! Success! I had a blast doing this. I need to snap a pic of my Samsung to confirm it's a mainboard issue and it'll be done too (I've got another post going.)

Then I'm off to tackle my Westinghouse that's been without HDMI for months. No longer afraid of tackling this sort of thing.

Thanks again to everyone who helped. Off to watch a movie...

EDIT: In case someone finds this post down the road, this TV does not have a pilot light. It's off when off and green when on.

[budm]

Re: Sanyo DP46849 46" LCD - Does not power up.

Glad you got it fixed, and thanks for the repair feedback.

[tom66]

Re: Sanyo DP46849 46" LCD - Does not power up.

Great! Looks nice