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Eng. Andres
Eng. Andres, Engineer
Category: Electronics
Satisfied Customers: 68
Experience:  Electronic Eng. Electronics Specialist. Circuit designer
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loss of picture on a panasonic th-42ph9.... tv is about 6 years

Customer Question

loss of picture on a panasonic th-42ph9.... tv is about 6 years old..... worked fine until installation of 2 hdmi terminal boards.....the first lasted 1 year, second about 3 months...., should I have switched on dip switches in terminal board when installing.......
Submitted: 4 years ago.
Category: Electronics
Expert:  Aric replied 4 years ago.
Hello, My name is XXXXX XXXXX I will be glad to assist you. Please keep in mind that there may be a few minutes between replies, as I research your problem.

How long have you had the set for and when did the problem occur?
Additionally, what is connected to the TV for devices (DVD, cable box, etc.), and do you have the same issue regardless of which Device you're watching?
If you press MENU on the TV when the problem is occuring, does the MENU display normally on the full screen?
Customer: replied 4 years ago.

I've had tv for 6 years, the problem with the hdmi terminal board's happened last week and last month, devices were sky box and blu ray player ........there is no picture on the screen whatsoever

Expert:  Aric replied 4 years ago.
Thanks for the reply.

I'm not sure if you're saying you replaced the HDMI jacks on the Mainboard, or just that you were plugging HDMI devices into the TV. Was any work done to this set, or are you simply saying the HDMI ports are no longer working?

Additionally, do you have a no signal message on the TV?

If you press MENU on the TV itself, or Volume, do these things show on the screen right now?
Customer: replied 4 years ago.

I believe the hdmi ports are no longer working. I replaced a scart terminal board with an hdmi terminal board last year to connect to my sky box, that stopped working last month. I replaced a component terminal board with another hdmi terminal board 3 months ago so as to connect my blu ray player this failed last weekend. It seems to much of a coincidence that both have failed within a month of each other. I've noticed that they have switches ( if I remember rightly numbered 1to4)
inside the terminal board, could these have anything to do with loss of picture?

Expert:  Aric replied 4 years ago.
I see what you're referencing now. I unfortunately have no information regarding switching one style of board for another, and this is beyond my expertise with the set. I will need to open the question for other experts to assist you on this one.
Expert:  TV-Tech1 replied 4 years ago.

You stated--


I've noticed that they have switches ( if I remember rightly numbered 1to4)


Those switches should be set to the same settings your old module is set to. Since you have the ability to switch from Scart to HDMI or set Component to HDMI you have to tell the replacement module that it's now occupying Input 1 or Input 4 on the TV set. If you attempt to install modules, you don't want all boards trying to occupy input #1, as that would conflict.


So the boards are set up to identify themselves. Also, didn't you get an instruction sheet with the modules? Panasonic sent them out with their modules when this TV set was newer.


As for the death of your modules...if anything I would suspect either the 5 volt or 12 volt lines powering them to be either too noisy or the voltage being too hot (5 volts at 7 volts or 12 volts at 15 volts) as that would slowly hurt the boards over time.


That or they are using "black market ICs" on the ones that you purchased and they failed.

We had problems with chinese IC makers building ICs that were substandard, and passing them off as the original ICs. We haven't seen that since the mid-2000's though....


So, power supply issues or "Black market rebuilds" come to mind with your problem.

Did you order them from Panasonic, or did you have to go to another supplier because Panasonic doesn't supply them ?



Customer: replied 4 years ago.

hi, thanks for info.. You said "Those switches should be set to the same settings as your old module is set to"... When you say old module are you speaking of the old terminal board? Slot 3 on the tv was originally a blank, if i were to put a new board here, should i set the switch to 3?...... I had to buy them them from another supplier, America methinks.... i installed them without setting the switches as i didn't know you had to. I read on a forum some time after installing them that a new hdmi terminal board in slot 3 should be set to my tv seemed to be working ok i ignored this advice...... still not sure if this would be the correct setting, as i would have thought that a new terminal board going into slot 3 should be switched to 3. Any ideas?

Expert:  TV-Tech1 replied 4 years ago.
I'll have to dig up the information on that. I had one customer in the USA several years back with your chassis, and I think when I called Panasonic about it, they said their modules came with an instruction sheet showing the settings for the HDMI and component boards.

In all honesty...if it isn't broke....don't fix it.

But this is what I would experiment with. Remember the board's ORIGINAL setting. Make note of it. Try the suggested setting, try the 3rd switch. See what happens. It won't hurt the board you install, but you may lose that input being sensed by the TV set.

In all honesty....I THINK the boards may have an AUTO-SENSE setting where the TV scans all the boards and assigns them Input names. Kind of like Plug and Play on Windows. Set it and forget it.

Anyways, this setting is not what is killing your boards. It can't hurt it. I'm more concerned about either bad parts being sold to the rebuilder, or the power supply having dried out capacitors, noisy regulators that could slowly be eating your modules.

Right now, I'm just trying to develop a Picture of the whole situation you are in.

I had to buy them them from another supplier, America methinks.
Hmm, ShopJimmy is a UK/US supplier, and they.....I trust
(ok, laugh at the grasp of my English. It's 9 am here and I only had one cup of coffee)
I'll dig a little deeper on this, see if I can convert the UK model to the USA model -- The only difference is the power supply and the main board/Video conversion modules

The fact is that Panasonic builds a universal frame and just switches boards to connect to the outside world. Keeps costs down.
Customer: replied 4 years ago.

"In all honesty..... if it isn't broke.... don't fix it". It's broke there's no picture. I bought the terminal boards from America (Provantage methinks) as there's no place else to buy them. I'll play around with the settings tomorrow.

Expert:  TV-Tech1 replied 4 years ago.

I'll make a list of power supplies -- TXNP1ZKTU


Those are the only sites I could find for your part.


Now, On the power supply board, there are 2 capacitors that filter the 15 volt line before it enters the first regulator, Q555 on that power board. They are C556 and C557 located near the transformer that creates the 15 Volt supply.

There is a 2nd level regulator for the lesser voltages of 3.3, 5, and 12 volt supplies, and those likely are good. The first level reg....that could be getting "noisy 15 volts" from dry or bulged capacitors, and to me that's the only thing that would cause multiple board failures. But that's an educated guess. That same supply drives a lot of the boards in your TV set, much like 220 serves you and others in your neighborhood. If you have problems and your neighbors have problems, I would assume the 220 was at fault. In your case, if the 15 volts was beating up on your Video modules, I would also expect to see other symptoms showing up in the picture and the sound circuits too.


We're not seeing that. So the power supply board, I wouldn't replace it. But I would look the caps over and see if the top of them are flat or bulged like this --



Bulged caps are bad caps.


HDMI module --TY-FB8HM


As far as the switches....I'd leave them alone. I didn't find one bit of evidence they need to be changed.