Funky Problem with HDTV

Kai

That Limey Bastard
Staff member
Okay, now, granted, i shouldn't be having a moan, but, i fished a 32" LCD Flatpanel out of a skip earlier today, and it works, for the most part, but, lemme explain...

Now, this thing has one or two very minor scuffs on it, not a problem. However, when using the HDMI to my PS3, its 95% perfectly fine - no panel problems at all, just every minute or so, the screen will kind of flicker, for a split second, and be normal again.

When using the SCART to my Satellite reciever, the audio is A-OK but the flickering is constant, as though its an old analogue TV thats not been tuned right, tilting the unit forward makes a 'klunk' noise and the flickering changes into vertical blurring.

I'm pretty sure that the panel itself is fine, and it's an issue with the electronics inside.

I studied Electronics at School, upto A-Level, i've got multimeters and tools, soldering irons and the like - BUT is this worth repairing, in order to save £500 on a new telly?

Incidentally, the model of the TV is thus;

Manufacturer: DUAL
Model: DLCD3221
Size: 32"

Any idea where i can get either a) schematics* or b) replacement parts?

* - Manuals in the 1980's used to actually come with the schematic diagram for the thing, now they barely say 'plug it in' - grr!
 

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Kai

That Limey Bastard
Staff member
Okay, so, this morning i decided that rather than waiting, and before i got too tired, i'd take the back off and have a poke around.

Turns out, theres not actually a lot inside an HDTV other than the Panel and 4 PCB's. Also, from the markings on the PCB's, it looks like its actually just a rebadged Hitachi 32".

The main signal PCB was a little loose, so i unplugged it, unscrewed it from the frame and inspected it. There were WAY too many dry joints on the PCB, around the tuning crystals, SCART sockets and the LVDS plugs.

So, i whipped out my fine Antex soldering iron, a roll of my thinnest solder, and set to work. Surprisingly, it took only a few minutes to get all that dealt with. Rather than just replace that PCB and put the back on, i decided to inspect the rest of the PCB's and check for other dry joints, loose connections etc.

Just as well really, the main power board had its main cap just flopping around on the board, held on by one dry and one cracked solder joint - hence why when i smack it, it was working - intermittent contact with the board.

The potting compound/glue gun crap that was also holding it to the board had gone dry and wasn't securing it at all. Out came the x-acto knife, and i sliced all that off. I resoldered the cap to the board first of all, waited a minute for the joints to cool off and then re-glue-gunned the cap the board, securing it tightly.

After that, all the PCB's were tightly (but not too tightly) screwed back onto the frame, plugged back in, and the back went on easily.

So of course, moment of truth.

Plugged it in, hit the main power button, and i didn't explode! :p

The standby light came on as usual, and i pressed the power button on the front. TV turned on fine. Plugged in both the SCART and HDMI inputs and hit the source select.

My Sky Digibox EPG was displayed PERFECTLY! No snow, no pink & green spots, no flickering, no blurring or distortion. Switched to the PS3 and it too, was perfect, with no jumping or any artifacts.

Of course by this time, i was tired, so i got back into bed after tidying up, and watched about 3 hours of Stargate SG-1 season 1 before i fell asleep, with the TV still on.

Woke up and its STILL working fine, no glitches. Tilting it doesn't make a 'klunk' noise anymore and no matter the orientation, it works A-OK.

So much for needing schematics! (although i'd still rather have a set)
 

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Doward

Banned
Jan 11, 2006
4,245
0
36
Alachua, FL
Wielding a soldering iron without burning yourself is harder than you might think to most people ;)

Love the work, though, Kai! Should have gotten some high-res pics of the dry solder joints. I love how shitty everything is made these days :3d_frown: