My tv has ripples in the screen how do i fix it?

Is the strobe light affect the entire screen? or just a part of the screen? I would say you either have a problem with the inverter circuit or power supply. You need to ensure that the inverters are being fed a clean 24vdc. If you are getting ripple voltages in the 24vdc power supply, your backlights will flicker. Also check the inverter boards and also the power supply capacitors for any bulging tops. I would also suggest you monitor the "backlight on" signal from the main board. It should be around 3.3 Vdc and again no ripple.

Sounds like you have a defect LCD panel tab !!! These are also common with Samsung LCD's as well. The only permanent fix is the replace the panel which will cost as much as a new TV in most cases.

If you cracked the screen, it is time for new TV since the screen will cost you more than a new 42" TV.
You can sell parts on EBAY.

Basic LCD monitor and TV troubleshooting guide:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
http://www.fixya.com/support/r7406380-tv_training_manuals
Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm
Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague
Parts: www.shopjimmy.com
Parts: http://interliquidparts.com/

Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx he can make you a set of caps.
Or www.digikey.com, just make sure to use caps with low ESR, 105c, high ripple current and long life rating such as PANASONIC FM or FC series.

this sounds like 60hz or 120hz a/c ripple distortion. if taping tv corrects temporarily, ther must be poor solder on main a/c ripple filter. very large usually blue capacitor near power cord input on pcb. do not short positve and negative legs together as you could be shocked(even after tv is unplugged) and also cause more damage to tv. these filters can store electrical charges for days, even if unplugged the whole time. careful! mch

You will need to contact a Mitsubishi Authorized repair facility. The entire electronics package must be removed and sent back in to Mitsubishi. The problem is the Formatter circuit board which is no longer available as a replacement part. The repair cost is very expensive and must be quoted by the facility you contact not me. Expect 4-6 weeks turnaround.

Sounds like you need to replace the Caps in the Dm board there are 4-7 of them if you send me pics I will talk you through it!

You will get a better response if you pay for the expertise we have to offer!

Check your screen. I have the same problem with mine. If the screen has a ripple in it, it could give the same effect.

Hello bouloulou, Well let me tell you what you have is a loss of Vertical Linearity. This could be cause by a power supply issue or by inproper filtering of the dc voltage used to supply the vertical section of the TV. There used to be a control which allowed you to adjust this along with Vertical Size which controled the bottom of the screen. These days the signal processor chip takes care of this along with a few capacitors. I woould suggest that if you do not have a background in electronics that you take the set to a shop for repairs, If you do have a background in electronics, get a schematic for this set and the use your multimeter set to DC volts to measure the DC levels in the vertical section of the TV. Also you will need an oscilloscope to measure the ripple voltage on the DC power supply the schematic will show you how much ripple is allowed. I hope this helps. Thank you, Shuttle83

The noise from the TV is called 60 cycle hum and it is caused by a capacitor that is open, a test for ripple voltage will confirm this The noise from the VCR is more then likely common mode noise which would not be heard but for the bad capacitors in the TV. Simply put the common mode noise is being added to the 60 cycle hum. Now for how to fix this, if you have a background in electronics you can use a schematic, multimeter and an oscilloscope and Multimeter to find the bad capacitors, and the schematic to tell you what the voltages and %ripple should be. If you do not have a background in electronics, take the set to be repaired