TV Repair - Panasonic TH-P42X10A

[Polybus]

Howdy Gang,

I'm having a go at repairing my Panasonic TV - TH-P42X10A.

Symptoms - None.  Completely dead. No power on LED - Nothing.

My first thought was a blown capacitor in the power supply - its about that age - 25 years old or something like that.

Pulled the back off - on visual inspection - all the caps "look" OK - no swelling/bulging/leaking etc - and no other outward signs of nastiness.

So start from the start. 

Power is definitely coming out of the wall.

Power is definitely getting through the power cable - 240v at the plug end where it goes into the TV.

Power is definitely going into the Mains line filter.

Hmmmmm - only  4 or 5 volts AC coming out of the filter and going to the board.

I've got to admit I've got very little idea about this filter. Its a  TDK-Lamba EMC Filter.   RPEN-04808EA-00A (photo attached).

Should I expect 240v AC out of this?

If yes - well - looks like I've found the trouble - replace this (or maybe open it up and see if there is anything fixable inside), and it should be good to go.

If no - well then I'll keep tracing things down the line.

Yes, yes, yes....if it is the filter - they are pretty cheap. but what would I learn from simply buying a new one and plugging it in - I'll have a look inside to see if I can fix anything just for the fun and see what I can learn.

Thanks for your advice

[coromonadalix]

check this manual,  you may have some similarities between the psu section(s)

https://www.manualslib.com/manual/1033198/Panasonic-Th-P42s10a.html?page=38#manual

Normally for a case like this,  you search for the psu part number, and you try to find the right service manual ... the same psu can be used on many models, a reverse search sometimes provide some good results


First you should check any standby power supply voltages, you should have at least a constant / standby 5 volts dc  going out somewhere ...



other manuals here
https://www.schematicsunlimited.com/p/panasonic

This link   : check for the pdf file version, you get a part number and somes infos ...
https://archive.org/details/Panasonic_TH-P46S10A_TH-P42G10A_TH-P42X10A_TH-P50V10A_TH-P42X14A_TH-P42S10A_TH-P/mode/2up

[Polybus]

Thanks heaps for the reply - that manual should come in very useful.

It got me back to the TV with my multimeter - which turned out to be just a little embarrassing.

On second inspection - I AM getting 240v out of the filter - so I will now progress onto the Power Supply Board.

Don't ask what changed between my first post and now - suffice to say I am an idiot and leave it at that!!   

Let's see how I go from here.

Thanks again.

[Ed.Kloonk]

Thanks heaps for the reply - that manual should come in very useful.

It got me back to the TV with my multimeter - which turned out to be just a little embarrassing.

On second inspection - I AM getting 240v out of the filter - so I will now progress onto the Power Supply Board.

Don't ask what changed between my first post and now - suffice to say I am an idiot and leave it at that!!   

Let's see how I go from here.

Thanks again.

I very long time ago, as a boy, I wanted to fix a 3 in 1 furniture style TV/radio/gram. This thing was massive and it had a black and white screen. Only the TV part was not working. So, being safe I pulled the power cord and unscrewed the plastic back cover.

Something happened, I got called away. When I came back, I poked around this thing with my analogue meter and wasn't getting any voltages anywhere. Was the multi meter broken? Now the radio doesn't work. What the hell.

I mucked about with that thing for, I dunno, half an hour before I realised that the power cord was unplugged.

 

[Polybus]

OK - seeing as you were honourable enough to fess up.....

When I tested the output from the Mains Filter the first time (the cable was plugged in  )  I was only getting 4 or 5 volts.

But......the room was quite dim, my eyesight is getting poorer with age, especially in poor light, but I was getting a voltage.....

When I revisited it, I got serious, bright lighting and eye glasses.

Whats that I (now) see - the neutral coming out of the Mains Filter was protected by clear sleaving - and I was touching my multimeter probe onto that!!

ChuckleHead!!!!

Geeeeeez - you can even see the sleave on the photo I posted of the filter!!!

D'Oh!!!