partly faulty technika tv

[mark_101]

Hello everybody,
I'm new to the forum which I come across looking for a fix for a technika TV I was given. I wonder if anyone can help identify the problem, or give a pointer on what to try to find a fix. Unfortunately though, I have pretty limited equipment to work with (a DMM, soldering iron and a magnifying eyepiece!)

The model number is LCD19DVDID-107.

The fault is that there is no DTV reception, and the DVD doesn't work. The TV operates as it should with a Scart input.

The symptoms of the faults are:

with DTV selected, the screen shows white, with the green DTV ident in the corner, then the "no signal" banner is displayed. This happens when a know good aerial signal is connected;

with DVD selected, the screen shows white, with no ident, and no functionality from the dvd drive.

I have tried the following so far. A visual inspection of the motherboard, PSU and what I take to be the DTV tuner board. I noticed a few bulging electrolytics, which I replaced, one on the DTV board, 3 on the PSU. I noticed a few pathces of flux which I cleaned up. There looks like a bit of bleeding/leakage from two low profile transformers on the PSU ( I guess these are for the screen which is functioning correctly) I reflowed some joints on the DTV card (pins from the tuner module), and on the PSU just to clean up a bit. I measured 12v supply to the DTV board on the red/black 2 pin connector. I didn't know which pins carry power to the DVD drive, but I did measure 12v on at least one of the pins on the ribbon cable. The faults were the same after the above actions.

After that I'm at a bit of a loss. I would be very grateful if anyone has any ideas on how to identify/fix the problems, any help would be much appreciated. Of course I realise this is a low value item, so a repair would need to be econimical, but it would be a shame to junk it at this time.

Sorry for the rather long post,

Mark

 

[quantumtangles]

Is it really worth the effort?. Probably not. Other than for educational purposes, you have to be clinical about TVs, much as we all like to fix things and avoid waste. Nowadays, people give TVs away (on a collection only basis) on Ebay.

I recommend a refined form of Dumpster diving instead. Go to your local recycling centre. Bring a flask of coffee and electronics magazine. Wait beside the TV dumping area (most large towns have a special spot for leaving unwanted TVs).

Do not remove anything from the dump without permission. That would constitute theft.
Do not bother asking for permission from recycling centre personnel to remove a TV (health and safety regulations prevent them giving permission).

Instead, wait patiently (on a Saturday morning or Saturday afternoon) until you see an expensive 4x4 slide up to the TV dumping area. If they carefully begin lifting a cool 50 inch plasma from the trunk, ask them (before they dump it) what was wrong with it. Odds are it needs a couple of new electrolytic caps. If they give you permission to have it at your own risk, thats fine

Only do this if you are an electronic engineer qualified to handle defective mains operated electronics (for safety reasons).