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Equipment Repairs => LCD TV forum => Topic started by: donnachaidh on August 19, 2011,07:25:20

Title: TECHNIKA LCD32-209 Blank screen cure!
Post by: donnachaidh on August 19, 2011,07:25:20: Hopefully this will help someone!!
I managed to repair the Power Supply (17PW26-1) used on this set: Symptoms being blank screen, no backlights apparent and with only the front blue LED illuminated. I removed the Power Supply and visually checked the electrolytic capacitors for signs of distress (bulging etc.,) but all looked OK. Using a continuity meter (one with a Piezo sounder) I then went round all of the solder joints of all electrolytic capacitors by applying the meter probes to charge and discharge each capacitor - you will hear a little 'bleep' from the meter as each charges up. Reversing the leads will discharge each capacitor and again a 'bleep' will be heard. Each 'bleep' will vary in duration depending on the value of the capacitor. The bigger the value the longer the 'bleep' (charging time). I found that three capacitors indicated 'dead shorts'!! (bleeper on continuously whilst probes applied) - I unsoldered each one only to find that when isolated from the board they all checked out OK!! I then searched around the same area of the board to check other components, this resulted in detecting that D881 (BYV27-200) rectifier diode was also indicating a 'dead short' (checked in both directions using the continuity meter). Removing this component, and rechecking out of circuit, showed that it was indeed short circuited. Having a replacement to hand I then fitted this to the board, reassembled the TV and it is now in perfect working order.
Title: Re: TECHNIKA LCD32-209 Blank screen cure!
Post by: markie76 on August 21, 2011,16:10:08: HI,

Welcome to the forum! And thank you for posting the tip :thumbup:
I have a Technika LCD26-207 with BLACK screen (backlights are on but screen blank - black) but sound is ok.
On mine the blue LED comes on when in standby.

Can you clarify;
By blank screen do you mean the unit wasn't powering up? (switching on)
You had sound but no picture?
You had sound and picture but the backlights were off?

Thx
Title: Re: TECHNIKA LCD32-209 Blank screen cure!
Post by: Turnip on August 24, 2011,13:13:08: Hi Markie76,

If you discover a duff board (prob Main or LVDS with duff fuse) I have a screen smash set - all good panels

PS - check fuse on LVDS panel - they pop for no reason
Title: Re: TECHNIKA LCD32-209 Blank screen cure!
Post by: markie76 on August 24, 2011,14:33:32: Quote from: Turnip on August 24, 2011,13:13:08
Hi Markie76,

If you discover a duff board (prob Main or LVDS with duff fuse) I have a screen smash set - all good panels

PS - check fuse on LVDS panel - they pop for no reason
Have given the LVDS the once over, fuse ok and voltages seem ok.

Have been told would need to test the signal coming off the main and then trace back from there.
This unit looks like it had the panel replaced as its a Samsung unit - so I'll probably just look for a broken screen 26" tv which this good panel can be put in :)
Title: Re: TECHNIKA LCD32-209 Blank screen cure!
Post by: Turnip on August 26, 2011,12:37:14: Hi Markie76,

If your suspect main board is 426109-37999 rather than the usual Vestel 17MB45M-2

Have one from a screen smash, also the LVDS - Chris.
Title: Re: TECHNIKA LCD32-209 Blank screen cure!
Post by: markie76 on August 28, 2011,08:43:00: Quote from: Turnip on August 26, 2011,12:37:14
Hi Markie76,

If your suspect main board is 426109-37999 rather than the usual Vestel 17MB45M-2

Have one from a screen smash, also the LVDS - Chris.
The main board is the vestel one....:(
Title: Re: TECHNIKA LCD32-209 Blank screen cure!
Post by: Turnip on August 29, 2011,13:22:28: Hi Markie76,

Also have a Vestel 17MB45M-2 from a screen smash Technika - Chris.
Title: Re: TECHNIKA LCD32-209 Blank screen cure!
Post by: markie76 on September 02, 2011,15:13:32: Thanks for the offer but I think as this is an old model I'll just keep the screen and try to pickup a samsung with smashed screen to put it in :)