20 Most Recent Philips 42PF7421D 32 in. LCD HDTV Questions & Answers

The main power supply regulator section circuit fault. Either it will be a separate board, or the part of main board. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Pull up older posts. http://electronicshelponline.blogspot.com/

The TCON board or the LCD panel is faulty. Can conform by replacing the TCON board . If you wish to get some details; visit the site linked here. Pull up older posts. http://electro-medical.blogspot.com/

the tcon boar or the lcd panel is faulty. can confirm by replacing the tcon board . If you wish to get some details; visit the site linked here. Pull up older posts. http://electro-medical.blogspot.com/

If it is the model indicated here--no "bulb" Perhaps if I knew the issue and you confirm the above model number I could help?

Tv turn now,have pictures flashes only a few sec than died and have sound left only?Yes,than those 1 or 2 long boards call the LCD inverter boards are dead.These 1 or 2 long LCD inverter boards help the LCD screen panel to have a backlight to produced a picture.Tries websites like Shopjimmy.com,Ebay.com to buy those 1 or 2 long LCD inverter boards for the replacement.

It may be in safety shutdown due to short cicuits in the power supply or in the backlight inverter board, those are the two areas you need to check first.
If you are going to DIY and have proper tools, electronics knowledge, and know safety precaution then please read on:

Please see my basic troubleshooting guide here:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide

http://s807.photobucket.com/home/budm/allalbums

http://en.wikipedia.org/wiki/Capacitor_plague

Parts: www.shopjimmy.com
Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx

Please post back what you find.

Flashes usually indicate an error code. Unplugging it and trying it again and getting it to work would point to the power supply assembly. Not a job for the DIY'er. High voltages....

normally that sounds like a power supply failure

even if the caps look ok check the secondary side of supply rails for ripple or voltage outside of specs.

this is a common problem on these units the caps are (as far as i can remember) are 3300 10v , 100 16v , 1000 35v 330 16v

the other problems i have had with these sets is the resistors that drive the relays going high in value.

Hi, philips (sony and others) uses the flashing red lights to give an error code, but all that means is that a circuit is probably shorted and doesn't always indicate specific components,.
42pf7421 is an LCD that basically has two large circuit boards in it. If you have technical ability you can examine the power supply to see if any capacitors are swollen on their top sections. this is a common failure in many LCDs and Plasmas, but would require soldering to replace them. If no caps look swollen troubleshooting this set would involve voltage checks , a service manual and board replacement.
Could be either the main board, power supply or possibly a bad screen (panel) If you have the set open you can sometimes see the LCD bulbs light for a split second indicating that a problem with either the panel itself or the ballast power section. If it lights for a second sometimes I can see that one bulb is not lighting. One bad bulb will cause the set to go into shutdown mode , indicating a bad screen (panel) .
I hope this info helps you decide on the options before you
1. call a tech expect to pay an estimate fee, parts and labor btwn $200-$1000
2.check the power supply, reseat the panel cable, look for a momentary light of the screen. order a suspected part and replace it yourself.
3. buy a new TV (sry bad option)
hope this helps
Eric I’m happy to help further over the phone at https://www.6ya.com/expert/eric_ab7c09ec01841771

Ur power supply board is dead,pop propally the capacitors pop,puff up.Check replaced the capacitors.Or replaced the whole power board.

It's the power supply, Call JVC and see if they will fix it for you.

Granger1212 we had the same problem. We called LG and although our LG was out of warranty by 4 months, we were asked to supply our proof of purchase and LG sent a serviceman to our home and in 2 days we had our television back working wonderfully. It's the power supply, call LG and BE NICE, I'm sure they will fix it.

The most common cause of this is a defective button assembly on the front of the set. With the set unplugged, try pushing each of the small buttons on the front panel. You should be able to feel them engage. They should all feel the same. If one does not feel like it is engaging, it is possible that it is defective. If the set is no longer under warranty, you can attempt the repair. Be forwarned that the panel is extremely fragile and can easily be broken. Carefully place the set face down on a table that has been covered with a pad of some sort and remove the back cover. You should be able to see how to remove the front panel board assembly. I'll try to get the part number and post it here.

Some times a little dirt gets into these tact switches and can cause odd behavior. Try pushing each one a few times while unplugged and see if that clears it. If not, replace the switch panel. It is possible that a low 5V supply can cause this as well, but usually other symptoms show up too.

Please keep us posted.

Thanks,
Dan

burn in run  a white screen

If this is only happening on one input like your cable input and the dvd player is working great on a different input, then the issue can possibly be signal related and not a problem with the tv, if this haapens on any input you are watching, check to see if it affects the menu if it does then your looking at a Logic board issue, if it doesn't affect the menu but happens on multiple inputs then you have to replace the signal board

Remove the cover on the back of the tv. Look for swollen or leaking capacitors. They kinda look like batteries. If they are bulging or leaking then that is your problem. You will have to de-solder the old ones off. Then solder the new capacitors onto the circuit board. Capacitors will cost about 20 dollars and installing them isn't that hard to do. It will fix your tv 99% of the time. So it is worth a try!

I'm assuming that you have checked that the sound is not muted. To confirm that a reset to factory settings is the next procedure: Menu - Setup - General - Factory settings. If you don't see/hear any modifications then it's a hardware defect, not something with the settings.
This happens when the tv thinks that the headphones are used. Simple test to confirm that: plug in a pair of speakers and see if you get the sound on them. If you get and the situation doesn't changes when you unplug them then this is a mechanical defect: the small switch inside the headphone jack is faulty and keeps signaling that the headphones are plugged in when they are not.
The only way to fix that is to replace the jack, which involves a very delicate soldering procedure , one that only a good repairman can do - you must call one.