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medeion lcd monitor fault
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ekim
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PostPosted: Fri Jun 08, 2007 11:02 pm    Post subject: medeion lcd monitor fault Reply with quote

hi all
im having a problem with my medion md 30917 pn monitor,
its stopped workin, im getting a fast flashing blue led on the front panel.
i have opened it up and found several capacitors 470uf 25v, that have swollen on top near the power supply. im just wondering if the could be the fault. can anyone confirm this before i start to remove them from the circuit board.
thank you
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rsfusion77



Joined: 17 May 2007
Posts: 37
Location: Miami, FL

PostPosted: Mon Jun 11, 2007 3:45 pm    Post subject: Re: medeion lcd monitor fault Reply with quote

ekim wrote:
hi all
im having a problem with my medion md 30917 pn monitor,
its stopped workin, im getting a fast flashing blue led on the front panel.
i have opened it up and found several capacitors 470uf 25v, that have swollen on top near the power supply. im just wondering if the could be the fault. can anyone confirm this before i start to remove them from the circuit board.
thank you


I would definitely check those caps with esr/cap checker and while you're at it, check entire secondary side (of smps) for leaky/shorted semiconductors.
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torbjorn



Joined: 07 Jun 2007
Posts: 370
Location: Sweden

PostPosted: Tue Jun 12, 2007 7:48 am    Post subject: Reply with quote

If an electrolytic capacitor is swollen, then it isn't worth measuring capacitance and ESR, just replace it anyway! But make a thorough check of all other electrolytics from the same manufacturer, especially if the monitor is manufactured around 2000-2003, when several far east capacitor manufacturers had quality problems.
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CJ
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PostPosted: Thu Apr 16, 2009 2:51 pm    Post subject: 17" Medion TFT Monitir Fault Reply with quote

After just over the 3 year warranty my monitor would not come on for between 5 & 15 mins after powering on and then work perfectly untill it was switched off.

Reading forums this appears to be down to electrolytic capacitors on the power supply card which may appear to be swolen or discoloured on the top..

There should be 6 x 470uF 25V and 1x 220uF 25V capacitor all rated at 105 degrees celsius.

In my monitor 4 of the 470uF parts and the 220uF part have swolen and appear to have a dark liquid on the ends (probably the electrolyte leaking)

Parts are readily available from Maplin Electronics at less than £5 delivered.
These are 220uF 50V part with a 4mm pitch and the 470uF 25V part with the 5mm pitch from the 105 degree celsius electrolytic capacitor range.
(Do not use lower temperature parts as these would fail quickly)

To check for this problem.
Make sure the mains is off and the lead disconnected from the back of the monitor.
Undo the four screws on the bottom of the screen, slide the plastic front cover toward the top of the monitor (this may take some effort). Reomove the 6 screws from the TFT screen module and lift way carefully.
Reomve the 5 cables going into the can mounted to the rear of the monitor, keep a note of which one goes where as some of the coulouring is the same for different connectors.
Undo the screws to release the top of the can.
Inside are 2 PCB's, remove the four screws holding in the top board (the power supply board) and pull away from the bottom board.
The 470uF capacitors in question are grouped close together and the 220uF capacitor is a small distance away.
If these look swolen or discoloured , change them.
To put back together just reverse the instructions above.
I hope this helps as it is still cheaper than a new monitor.
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PostPosted: Sat Apr 25, 2009 8:55 pm    Post subject: Re: 17" Medion TFT Monitir Fault Reply with quote

CJ wrote:

Undo the four screws on the bottom of the screen, slide the plastic front cover toward the top of the monitor (this may take some effort).


Hello there,

I'm having trouble with sliding the front off the monitor, am I missing something? I've removed the four screws at the bottom but it still seems awfully difficult to remove. Just wondering if you had any tips for this step.

Oh, and by the way thanks for the info on the capacitors, this monitors been sitting under the bed for like a year, so now I can get round to fixing it (dual screen setup again Very Happy).

Thanks again CJ. Cool
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anfonyl
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PostPosted: Sat Apr 25, 2009 9:38 pm    Post subject: Reply with quote

Well, five minutes after the above reply to CJ I finally got the cover off of the front . So hopefully it'll be smooth sailing from here on. Embarassed

Just double checking I've got the right components: maplin.co.uk/Module.aspx?ModuleNo=11992

Thanks for all the info again Very Happy.
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anfonyl



Joined: 29 Apr 2009
Posts: 2
Location: United Kingdom

PostPosted: Wed Apr 29, 2009 4:53 pm    Post subject: Reply with quote

Well it worked Very Happy

Just replaced the ones that had some sort of discharge coming out the top.

Shot with W610i at 2009-04-29

I replaced four of the 470uF 25V with four 470uF 75V's and the single 220uF 25V with another (just had a different name/brand - xunda -> Elite).

Shot with W610i at 2009-04-29
I took these replacement capacitors from an old monitor that was already in pieces so it was actually really simple to do. The hardest part was getting the front cover off the monitor, after that it was easy peasy.

thanks again for all the info above Wink
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Take of cover?
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PostPosted: Mon Jan 03, 2011 1:45 pm    Post subject: Reply with quote

hi, thanks for the help but i have the same problem, how do i remove the cover?
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jts1957



Joined: 24 Nov 2008
Posts: 2472
Location: Far, Far Away

PostPosted: Mon Jan 03, 2011 11:30 pm    Post subject: Reply with quote

Works for me...

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anfonyl



Joined: 29 Apr 2009
Posts: 2
Location: United Kingdom

PostPosted: Sun Mar 20, 2011 4:40 pm    Post subject: Removing the cover. Reply with quote

Take of cover? wrote:
hi, thanks for the help but i have the same problem, how do i remove the cover?


Yeah that was the hardest part, if I remember correctly you have to pry the back off with some force. I was pretty rough with it and didn't do any damage.
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