Acoustic Solutions LCD32805HD - No picture, working sound, backlight okay

[tom66]

Have a TV on my bench:
- No picture - but backlight works (i.e. screen has a slight glow and the holes in the rear of the set are lit up white)
- Sound works fine
- TV appears to respond to commands e.g. changing source, turning on/off and volume control.

I suspect the main board or T-con. How can I determine which has failed?

[tom66]

Re: Acoustic Solutions LCD32805HD - No picture, working sound, backlight okay

Here are some pictures of the TV.

[tom66]

Re: Acoustic Solutions LCD32805HD - No picture, working sound, backlight okay

Okay, so I got a new oscilloscope, just to take around with me to probe TVs and such. I tested the waveforms on the LVDS connector, and they are there - so I'm suspecting the T-con. Am I right in doing so?

[randtek]

Re: Acoustic Solutions LCD32805HD - No picture, working sound, backlight okay

That is a good possibility. You could try gently rocking the LVDS connector at the TCon board. If you see flickering/flashing, lines or noise on the screen while doing this, Your TCon is probably good. If the LVDS cable at the TCon is not easily accessible, you can also rock the LVDS connector at the main board for this test.

[tom66]

Re: Acoustic Solutions LCD32805HD - No picture, working sound, backlight okay

That is a good possibility. You could try gently rocking the LVDS connector at the TCon board. If you see flickering/flashing, lines or noise on the screen while doing this, Your TCon is probably good. If the LVDS cable at the TCon is not easily accessible, you can also rock the LVDS connector at the main board for this test.

Thanks. I did try that - nothing on the screen. The screen is completely black apart from the backlights.

Got the T-con out now and found a failed fuse on the board (CP101), so I'm guessing it's toast. The fuse is marked "P" and is probably 0603 sized. If I replace it, is it likely that the new one will blow? Otherwise I'm going to order a new one for £15 on fleabay.

[tom66]

Re: Acoustic Solutions LCD32805HD - No picture, working sound, backlight okay

Okay, I found a fuse in my junk box that fitted, and was a 3A/32V one (matching replacement for "P" marking I think.) Replaced it and to my surprise, it works! Good clear picture. Was expecting it to blow in seconds. Strange that the fuse would just blow after a few years of use.

[selldoor]

Re: Acoustic Solutions LCD32805HD - No picture, working sound, backlight okay

Was going to start a new post but found this. Odd all the posts on tvs and very few of them relate to poor sound.

Acoustic Solutions- poor Audio- Ironic eh?

Acoustic Solutions -Vestel PSU.I can imagine Tom66 diving for cover
Anyway £11 on ebay "doesnt always switch on" "Poor sound" "No remote"
That bit that always gets me why no remote- not like its any use for anything else!.

Well, seemed to come on ok for me - using a HD Freeview box it has a good picture on HD and SD but the sound is abysmal, (normal???).

Changed the middle range caps on the power supply to panasonic FR but didnt make any difference.
Plugged and unplugged all the Audio/AV Connectors.
It is the same using HDMI or Scart.
Removed speakers and soldered in some external Sanyo speakers I had lying around and it was much improved, but not great.(Dont really think it ever will be but just wanted other opinions.)
Tried all the alternative sound settings - not easy without a remote and my current "Universal" nor the one with the newish HD freeview box only manage to switch it on and off.
Tried plug in external speaker but could get nothing out of them - cant find any info on the menu to suggest I have to set them as "on" and the buttons are driving me mad and cant find manual either.

Pictures -
1 Power supply Vestel 17PW20
2 Main Board 17MB24H-2
3 AmpIC TDA1905
4 Audio Area of Main Board?
5 TDA1905 Datasheet PDA
6 Power supply Schematic PDA

Might the sound be improved if I were to change the 2 HEC 16v 1000uF caps or any other caps in the last picture or is it what it is, until I can find some decent speakers that will fit inside.


Quote from Current site:
"Vestel's web site is being regenerated to reflect its mentality and be more customer-friendly. Soon, from this new site, you can discover Vestel's all high-tech products like televisions"

[tom66]

Re: Acoustic Solutions LCD32805HD - No picture, working sound, backlight okay

Quick hint. Most Philips remotes also work with Vestel sets. And all Vestel remotes are cross compatible.

Both channels sound bad? Check 12V power. Got a scope?

[selldoor]

Re: Acoustic Solutions LCD32805HD - No picture, working sound, backlight okay

No scope - Both channels - as I say maybe im expecting too much ,its not so bad with the sanyo speakers just wondered what the opinion was on changing the caps on the main board - Great heatsink stickers eh!

[tom66]

Re: Acoustic Solutions LCD32805HD - No picture, working sound, backlight okay

No scope - Both channels - as I say maybe im expecting too much ,its not so bad with the sanyo speakers just wondered what the opinion was on changing the caps on the main board - Great heatsink stickers eh!

My guess would be that it is crap to begin with, most Vestel audio is an afterthought.

"What, you mean TV has audio too? Quick, cram it in on the board somewhere!"

[selldoor]

Re: Acoustic Solutions LCD32805HD - No picture, working sound, backlight okay

Yes - silk purse - sows ear springs to mind - thanks for the philips tip - might even have one somewhere. Will update thread when/if I change the caps.

[preytec]

Re: Acoustic Solutions LCD32805HD - No picture, working sound, backlight okay

Hi tom66, did this tv ever come back to you after you fixed the fuse? i'm having the same problem with one myself.
thank you