Sanyo DP58D33 Sound but no picture

[pop70458]

The backlight flashes for one second and then goes out but sometimes will stay on for a few minutes. I have sound and can see a picture with a flashlight. I have already replaced the mainboard.

[pop70458]

Re: Sanyo DP58D33 Sound but no picture

These are the voltages when powered on.

Two main caps 437


PS0N 3.4
GND 0
5VSTB 5.4
5VSTB 5.5
GND 0
12VA 13.8
12VA 13.9
GND 0
Audio Power 14.0
GND 0
Line off 3.7
BL-ADJ 1.6
BL-SW 3.7
Audio Power 14.6


LED 5- 3.7
LED 4- 23.4
LED 3- 22.9
LED 2- 22.9
LED 1- 23.1
NC 0
NC 0
LED+ 157.7
LED+ 157.9
LED+ 158.1
LED+ 158.1
LED+ 158.2

[johnboy1313]

Re: Sanyo DP58D33 Sound but no picture

I would suspect a failed LED string or maybe more than one. You'll have to open the panel and observe the LEDs when they light. Record a video of it and pause it when they are lit.

[skinner]

Re: Sanyo DP58D33 Sound but no picture

Were you ablet to fix it. I dont suspect a led string because the voltage coming from the PSU is wrong. The 3.7 is not correct, should be consistent with the other led-. I have the same problem but my led 5- is 22v and led 4- is 3.5v. I opened the panel and looked at the strips when they flash and the strip that is only getting the 3.5v does not flash with the others.

[CapLeaker]

Re: Sanyo DP58D33 Sound but no picture

failed LED's in the string like johnboy said.

[budm]

Re: Sanyo DP58D33 Sound but no picture

'I have the same problem but my led 5- is 22v and led 4- is 3.5v.' It is telling you that you have bad LED/s (HIGH RESISTANCE) on that string, the LED 1~5 are the return pin (Cathode of the LED string) the Anodes of the LED strings are connected to the LED +.

[skinner]

Re: Sanyo DP58D33 Sound but no picture

I want to thank you guys for the post. I was chasing that 3v not realizing its a return. I got it working now. Maybe just a bad connection, I swapped the bad led strip with the good one (half at a time) and now everything seems likes it working without replacing anything. I may have got lucky on this one.

{UPDATE}
Tapping on the connector where the 2 halfs of the led strip meet caused it to fail again. I soldered the 2 little legs and now they are not failing. Something for anyone else with this issue can try.

[Louis82]

Re: Sanyo DP58D33 Sound but no picture

I would like to add to this thread a successful repaired of Sanyo DP58D33.
Same issue, tv flashes for a second, sound remains but picture is gone. no glowing.

Found the loose connection (just like skinner mentioned before) between the 2 strips that in this case they were located on the bottom (t-con side)

Resoldered them and tv is working properly again.

[budm]

Re: Sanyo DP58D33 Sound but no picture

I have same problem with Sharp LC-40LE550U, the whole connector came off the board.

[CapLeaker]

Re: Sanyo DP58D33 Sound but no picture

must be that Chinese solder...

[In-Tech]

Re: Sanyo DP58D33 Sound but no picture

I would like to add to this thread a successful repaired of Sanyo DP58D33.
Same issue, tv flashes for a second, sound remains but picture is gone. no glowing.

Found the loose connection (just like skinner mentioned before) between the 2 strips that in this case they were located on the bottom (t-con side)

Resoldered them and tv is working properly again.

Hello, I have the Sanyo dp58d33 and am having the same issue, screen will come on for a few seconds then black with sound. I have the back off of the tv now but can't seem to find the circuit you guys are repairing. Does anyone have any better detailed pics of where this bad connection is? Thanks in advance.

[In-Tech]

Re: Sanyo DP58D33 Sound but no picture

Hello, here are pics of all the boards for reference. The pics are from my phone and I apologize if not clear.

[In-Tech]

Re: Sanyo DP58D33 Sound but no picture

I put it back together and it worked for about 8 hours then black screen again. Restart tv and it works for a few mins or seconds then black again. This is at home so I don't have much equipment here but will take to my auto shop soon. I am not as well versed on electronics as many here are. I do have a bit of equipment, 4 channel scope, hot air station, decent solder station, fluke clamp, old school HP freq counter, function generator, etc.
I am guessing but to me it acts as if it goes into a "safe mode" because something either goes "open" or drawing too much current and shuts off the backlight. I would really appreciate any direction.

I looked online for any updated firmware and didn't find any. I don't know the nomenclature like many of you do so pointing to a pic with a name would be really helpful. Thanks,
-Carl

[In-Tech]

Re: Sanyo DP58D33 Sound but no picture

I could not see any bad caps nor anything that looked like a cold solder joint. In the blind I bought a new t-con board. Is that a waste of time? I will be taking it to my shop this weekend once the new board shows and I will trace steps from there.

Any input is appreciated.

[budm]

Re: Sanyo DP58D33 Sound but no picture

So far the failure is due to open connection on the LED strip inside the LCD panel.

[In-Tech]

Re: Sanyo DP58D33 Sound but no picture

Thank You budm,
I have only had the back off and not tried to take it apart any more except to pull a few boards and flip over to check the underside.

I'll do a search here and on youtube for a quick tutorial of how to disassemble it further. If you(or anyone) knows of one and can point me to a link, that would be greatly appreciated.

I'm kinda guessing that most LED/LCD come apart pretty much the same so I'll keep my eyes open for other brands. I just don't want to break anything.

Thanks again,
-Carl

[budm]

Re: Sanyo DP58D33 Sound but no picture

Taking the LCD apart is the last thing you will want to do, so see post #2 as how the OP report the Voltage readings and do the same for us to verify.

[In-Tech]

Re: Sanyo DP58D33 Sound but no picture

I will do that and post the info but won't be able to for a couple of days, thanks again budm.

[ace88bull]

Re: Sanyo DP58D33 Sound but no picture

Going to resurrect this as I'm having an issue with my DP58D33. Sound, no picture, backlight is working, no picture with a flashlight, and I've replaced the TCon board with no change. Any suggestions of what to test or check?

Voltage on the power board with TV on:
PS-ON 3.19
GND -0.08
5VSTB 5.04
5VSTB 5.04
GND -0.10
12VA 12.33
12VA 12.33
GND -0.06
Audio Power 3.25
GND -0.08
Line Off 3.25
BL-ADJ 1.12
BL-SW 3.15
Audio Power 12.33

LED5- 27.2
LED4- 27.4
LED3- 28.7
LED2- 29.1
LED1- 27.6
NC Erratic
NC Erratic
LED+ 141.1
LED+ 141.1
LED+ 141
LED+ 141
LED+ 141