Sanyo DP55441 - Replaced parts still no picture

[coffeeman2000]

Hello All,
Recently picked up a non-working TV for 50$ (sanyo dp55441) like all projects I was thinking it was be an easy fix. The previous owner said his kid knocked over the TV backwards (no cracked LCD) and then the unit would not power on after.

Opened it up and reseated all the connections. Saw that when you use the remote or the TV buttons to power on, ONLY the front power light turns on. (No backlite nor picture). Decided to replace the main board…..still has same symptom. So in a last ditch effort I replaced the power board….Still same syptoms. Im at a loss.

What would be the cause of the power light to turn on but have no backlight AND no picture (shined a light on the panel while clicking through buttons to see if it had picture). I would think it would be rare for TWO inverters to not work PLUS a bad Tcon/PCB board.

Any help from this fine community would be great.

[Glitcher]

Re: Sanyo DP55441 - Replaced parts still no picture

it only takes one inverter to be defective in order for both to shut off.

[coffeeman2000]

Re: Sanyo DP55441 - Replaced parts still no picture

it only takes one inverter to be defective in order for both to shut off.

but that doesn't explain the no picture. Plus i have disconnected the power to one side of the inverter (and ribbon cable). still same symptom?

Do you have any input on that?

[tom66]

Re: Sanyo DP55441 - Replaced parts still no picture

Many LCD TV panels do not have a visible picture when not backlit.
A broken bulb may also case an issue.

[coffeeman2000]

Re: Sanyo DP55441 - Replaced parts still no picture

First, apologizes for not getting back to you guys sooner. Been traveling, secondly thanks for the reply, im truly at a lost and am looking for all the learning experience i can get

but that doesn't explain the no picture. Plus i have disconnected the power to one side of the inverter (and ribbon cable). still same symptom?

Do you have any input on that?

I DID, unplug the inverter from one side to see if i got a back-light. Nothing.

Many LCD TV panels do not have a visible picture when not backlit.
A broken bulb may also case an issue.

Actually i did not know this. That's a relief if this is the case. I wouldn't think the tcon board is the issue then.

So the next question is, whats next. I will be busting out the multi meter this weekend to start checking voltages. In the mean time, is there a way to narrow down whats the issue. So far we have concluded that, its both the inverters and the bulb.

Any specific tests we can do?

[coffeeman2000]

Re: Sanyo DP55441 - Replaced parts still no picture

UPDATE UPDATE!

Progress, so after this tv has been sitting i decided to retest the inverter boards. This time i disconnected the ribbon cable AND the power cable from each different sides.

This is what i get
http://sdrv.ms/1dD9Ei4

So the Right side inverter is unplugged from power AND the ribbon cable. It shows picture but as you can see the colors are TERRIBLE. The original mainboard was plugged in, so for kicks i replaced the board with another one i ordered.

This is what i get.
http://sdrv.ms/1dD9U0J

So my question still stands, whats next. Right off the bat (only thing accessible now) is the main fuse on the inverter which reads 0 ohms. Will have to take apart and see whats wrong.

PS: on a second side note, is there a reason why the first mainboard would be bad? (would a non working inverter be the reason for the bad colors). Just want to double check that the mainboard is really an un-related problem. No need to replace un-necessary parts.

[coffeeman2000]

Re: Sanyo DP55441 - Replaced parts still no picture

Would love someone to direct me to the next step. Looking to figure out which part of the salve inverter i need to replace.

Some other information that might help, When i unplug the top one, and i plug in the ribbon cables back up and power, when turning on, the whole backlite flashes on for a second then off again.

Heres the bottom slave
http://sdrv.ms/1hIiCgK

Heres the Top slave
http://sdrv.ms/1hIildJ

PS: you can right click and download original picture to zoom in for the detail.

[coffeeman2000]

Re: Sanyo DP55441 - Replaced parts still no picture



I'm 100% stuck, would love to learn and have experiance

[coffeeman2000]

Re: Sanyo DP55441 - Replaced parts still no picture

Still have this TV, working fun but would love to get the Inverter fixed still. Is there an easy way to tell which one needs replacing?

[tom66]

Re: Sanyo DP55441 - Replaced parts still no picture

Can't see above pictures talking about bad colours...

[coffeeman2000]

Re: Sanyo DP55441 - Replaced parts still no picture

**UPDATE**

Sorry for the missing pictures. I deleted them forgetting they were linked.

Heres where we stand. The TV powers up and looks "great" with the one side inverter not plugged in.

100% the problem is the left inverter. The question is, is there a way to test which part of the slave inverter is not working. I dont want to dump 50$ to replace them both if i dont have to.

[tom66]

Re: Sanyo DP55441 - Replaced parts still no picture

You can use a neon bulb, which when in an insulated packet, will glow in the presence of high voltage. This can help determine which inverters are working.

[Hamsterstorm]

Re: Sanyo DP55441 - Replaced parts still no picture

I'm having the exact same problem, I replaced the control board and got nowhere, popped the ribbon to the left end inverters and got the right side to light up. At this point I've reached the limit of my technical knowledge.

[gc386]

Re: Sanyo DP55441 - Replaced parts still no picture

coffeman2000 - Any update on your fix? I am having a similar issue trying to find out where to start.

[jstiene]

Re: Sanyo DP55441 - Replaced parts still no picture

Hello.thought I would open this thread. I have a Sanyo DP55441 that I was recently given. When I turn it on, the Green LED comes on for a minute or so and then shuts off. I have disconnected the inverters, TCON, leaving only the main board and power supply, thus removing any short issues from the inverters or panel causing my power off.

Hae anyone else encountered this problem?
Joe