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Anthony_Infotech
Anthony_Infotech, Technician
Category: TV
Satisfied Customers: 13922
Experience:  20+ years experience TV expert (field and bench) 9 approved qualifications in TV-ELECTRONICS
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Upon turning on my Panasonic plasma TH-420z77u blinks 7

Customer Question

Upon turning on my Panasonic plasma TH-420z77u blinks 7 times. Nothing appears on the screen.
JA: What's the make and model of your tv, and has turning it on been a problem in the past?
Customer: Panasonic Viera plasma TH-42pz77u. No, turning on has worked fine in the past. It is about 10 years old.
JA: Does the TV menu work? Do you have the same problem on all sources/inputs?
Customer: TV menu doesn't appear so can't change inputs
JA: How long has this been an issue? What happened right before this popped up?
Customer: 1 day. Nothing that I know of; turned it off the night before. Tried unplugging it for 10 min, then for 24 hrs.
JA: Anything else you want the TV expert to know before I connect you?
Customer: Don't think so. What is the charge for this service?
Submitted: 1 month ago.
Category: TV
Expert:  Aric replied 1 month ago.

Hello, Sorry you're having problems. Offhand the 7 blink code does point to a hardware failure in the set, which generally involves replacement of components in the Plasma display processing.

However it's worth it to try a hard reset, as sometimes the processor in the TV can simply have locked up.

The first thing you would try, is disconnect the set from power, then press and hold the power button on the TV itself (not the remote), for 10 seconds and release. Then plug the set back in, and also check that the power cord is connected tight at the TV as well. Press power once, and see if the set powers up normally. Try this procedure up to 2 times, and please let me know what happens.

Expert:  Aric replied 1 month ago.

Are you having the same problem/ same blink code please?

Expert:  Aric replied 1 month ago.

If so, then unfortunately this is an internal hardware failure- and not something that can be corrected via any settings or adjustments on the set (since you're not able to access them anyhow if the TV won't power up). This problem can happen due to several things. The power supply is a common cause of this problem. This typically will cost you $250-$300 to have repaired.
The other very common issues, are problems with the Sustain boards failing. They are responsible processing the Plasma display and are common failures for this type of TV. The average cost for this type of repair is around $400 parts and labor.
Given that a brand new 42" LED TV can be purchased for about the same cost as repairing this set, it may make more sense to put that same money towards replacement of the set- versus repairs.
However if you would like to inquire about repairs, or seek a 2nd opinion, you can use the link below to locate a shop in your area if you'd like:

http://www.tvrepairpros.com

Other than that, I'm sorry for the bad news and wish there were a quick fix.

If you need further assistance let me know. Before you go, PLEASE DO click at least a 3 STAR RATING, at the top of your screen. That is how I am credited for my efforts by the site. You can follow up any time as needed at no additional cost.

Customer: replied 1 month ago.
Performed the procedure 2 times and go the same results... turning on produced solid red light and slight flicker on the screen and then dark followed by off and then 7 blinks.
Expert:  Aric replied 1 month ago.

Thanks for the reply, and I'm sorry to hear that. Unfortunately this is an internal hardware failure- and not something that can be corrected via any settings or adjustments on the set (since you're not able to access them anyhow if the TV won't power up). This problem can happen due to several things. The power supply is a common cause of this problem. This typically will cost you $250-$300 to have repaired.
The other very common issues, are problems with the Sustain boards failing. They are responsible processing the Plasma display and are common failures for this type of TV. The average cost for this type of repair is around $400 parts and labor.
Given that a brand new 42" LED TV can be purchased for about the same cost as repairing this set, it may make more sense to put that same money towards replacement of the set- versus repairs.
However if you would like to inquire about repairs, or seek a 2nd opinion, you can use the link below to locate a shop in your area if you'd like:

http://www.tvrepairpros.com

Other than that, I'm sorry for the bad news and wish there were a quick fix.
If you need further assistance let me know. Before you go, PLEASE DO click at least a 3 STAR RATING, at the top of your screen. That is how I am credited for my efforts by the site. You can follow up any time as needed at no additional cost.

Expert:  Aric replied 1 month ago.

Do you need further assistance with this?

Expert:  Aric replied 1 month ago.

The site shows that since the question is open that you are still looking for help. Or, if you received the information you were looking for-could you please kindly rate my service POSITIVELY (by clicking a 3-5 star rating by scrolling to the top of the page)? Thanks in advance.

Customer: replied 1 month ago.
Are there troubleshooting steps I can perform myself? I have some electronics experience. I have seen web sites discussing specific boards to troubleshoot and possibly replace to resolve the problem. On the other hand, some of them indicate a complicated relationship between some of the boards and the plasma screen, making it difficult for a layman to tackle.
Expert:  Anthony_Infotech replied 1 month ago.

Hi my name is Anthony

7 blinks is usually one of the scan boards however I have had spurious error reports by these sets so the first thing you need to do is unplug the set from wall-power wait 5 mins then take out all the inputs inth eback of the set, wait a further 5 mins then press the on\off switch on the set itself wait a further 5 mins then switch set on as stand alone no inputs connected, let me know about this first please

Anthony

Customer: replied 1 month ago.
Anthony, thanks for the help. Could you be a little more specific about "taking out all the inputs in the back of the set"?
Expert:  Anthony_Infotech replied 1 month ago.

Cable box\dvd player etc

Customer: replied 1 month ago.
Ah, ok. I believe I have done this already and still saw the 7 blinks, but am repeating it now.
Expert:  Anthony_Infotech replied 1 month ago.

Please follow above as described thanks

Customer: replied 1 month ago.
7 blinks after the second 5 minutes.
Expert:  Anthony_Infotech replied 1 month ago.

OK you will need a volt\ohm meter and tools to get the back off the set its likely you will be changing a scan board and the buffers for that board (subject to the checks) let me know when ready

Customer: replied 1 month ago.
OK, I've got the back off and a copy of the service manual in front of me with tools including VOM.
Expert:  Anthony_Infotech replied 1 month ago.

Find the Vs or VSUS and VA or VDA test points on the power-board, set the meter to ohms put black lead of meter to metal chassis, red lead to each test point in turn , do you get a low ohms reading on any of those test points?(set disconnected from wallpower throughout this test)

Customer: replied 1 month ago.
No, 139K ohms and 3M ohms, respectively. (I didn't find a VA or VDA, just a Vd)