medeion lcd monitor fault

[ekim]

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

[rsfusion77]

[torbjorn]

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.

[CJ]

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.

[Guest]

[anfonyl]

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.

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

Thanks for all the info again .

[anfonyl]

Well it worked

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