TV Repair - Panasonic TH-P42X10A - Page 1
Forum section: electronics / repair

author: Polybus
author_rank: Contributor
timestamp: July 14, 2020, 06:44:42 am
content: 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

author: coromonadalix
author_rank: Super Contributor
timestamp: July 14, 2020, 06:54:39 am
content: 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#manualNormally 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 resultsFirst you should check any standby power supply voltages, you should have at least a constant / standby 5 volts dc going out somewhere ...other manuals herehttps://www.schematicsunlimited.com/p/panasonicThis 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

author: Polybus
author_rank: Contributor
timestamp: July 14, 2020, 07:21:28 am
content: 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.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: July 14, 2020, 07:39:20 am
content: Quote from: Polybus on July 14, 2020, 07:21:28 amI 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.

author: Polybus
author_rank: Contributor
timestamp: July 14, 2020, 08:05:04 am
content: 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!!!