Panasonic TH-42PY80 plasma 10 blink error code

[Dannyx]

Good day folks. Pretty difficult project on my hands here: got this Panasonic plasma which has the infamous 10 red blinks symptom which indicates the 15V rail doesn't start up OR that one of the DC-DC converters on the logic board (A-board) isn't functioning. The power board is an ETX2MM702MFH. To test this, I removed the power board from the TV and did what I always do when testing power supplies: identify the 5-Vsb rail and apply that to the ON pin, or whatever the case might be. It was a chore to say the least, because it turned out I have to supply those 5Vsb to TWO pins, not just one. Have a look at the schematic on page 33 (the PDF is too large to attach, so please visit the link and download it on your own if you wish to be of help): the two connectors that interest us are P12 and P7. P12 does have 5vsb on pin 10 (DESPITE the schematic saying 12v on that pin - I'm sure it's just a typo) and STB_PS on pin 8. I thought, fair enough: pin 10 shorts to 8 to send 5v to STB_PS which should turn on the board. I did that but I got nothing: neither of the relays clicked, so there was still no power coming into the board. Now towards the bottom of that page there's also P7 which has pin 6 TV SUB ON. So aha: 5vsb must go to BOTH this pin and the STB_PS pin, so I did that, the relays did click a couple of times, but apparently didn't stay on, because I got no 15V on any of the pins where it's supposed to go. From what I gathered, since I could not identify any shorts in any of the large semiconductors on the power board, it could be a faulty MC301 riser board towards the center of the board, more specifically the TEA1611T IC which is on that board. I've seen a guy repairing a similar model with the same issue in this way. The question is, say I manage to get a new IC like that (cost considerations aside), is this a common failure in these Panasonic supplies, or should I check something else before struggling ? It's not the easiest part to source and replace, so I just want to know what other potential faults others have found.

[Hombre]

Re: Panasonic TH-42PY80 plasma 10 blink error code

Change the leaky ceramic capacitor on both MC301 and MC201 modules and it should fire up
Use search function for the details here on the forum, plenty of posts about this!

[attainteddragon]

Re: Panasonic TH-42PY80 plasma 10 blink error code

a quick freeze should confirm that it is dodgy.

[Dannyx]

Re: Panasonic TH-42PY80 plasma 10 blink error code

U mean this thing ? In the video I saw, the guy says it's a 1uf cap and replaces it with an electrolytic one. Guess there's no hurting in trying the same thing. If it still doesn't work, I reckon the next step is the IC itself.

[vinceroger69]

Re: Panasonic TH-42PY80 plasma 10 blink error code

yes too your post above its usually just that little smd cap and yes i used a normal electrolytic one too i have done a few of these sets now and never had to replace the ic i just replace the two capacitors make sure you note each board if you remove them to replace the capacitors as they are slightly different.

[attainteddragon]

Re: Panasonic TH-42PY80 plasma 10 blink error code

yeah, that's the one. with an electrolytic, the negative lead goes to the top pad.

[Dannyx]

Re: Panasonic TH-42PY80 plasma 10 blink error code

Gotcha. I checked by putting one probe of my meter on the top side of the cap and the other on the negative leg of the large bridge rectifier and sure enough I got continuity, since primary ground is common across all components there, big or small. Will try it soon...won't even remove the risers - I'll botch it to see if it starts at all and THEN worry about cosmetics

[vinceroger69]

Re: Panasonic TH-42PY80 plasma 10 blink error code

try just removing them and powering on the set as theres a few threads now people have just removed them and the set runs fine although for peace of mind i always put new ones on.

[Dannyx]

Re: Panasonic TH-42PY80 plasma 10 blink error code

The TV lives once again Replacing the cap on MC301 solved the issue. Cheers guys

[Fisher77]

Re: Panasonic TH-42PY80 plasma 10 blink error code

I had the same issue, replaced both caps, and the 10 blinks went away. TV will still not turn on, and now has one blink every 3 seconds. Any ideas?

The service manual says to check the A board, check it for what?

[Dannyx]

Re: Panasonic TH-42PY80 plasma 10 blink error code

I had the same issue, replaced both caps, and the 10 blinks went away. TV will still not turn on, and now has one blink every 3 seconds. Any ideas?

The service manual says to check the A board, check it for what?

One of the DC-DC converters on the A-board is probably faulty. The PSU board doesn't actually provide the 5v and 9v required to run some of the components on the A-board - those are generated on the A-board itself from the 15v bus coming from the PSU. One of these voltages is not coming on, or a faulty tuner unit is pulling down the 9v bus, since the tuner is the only component that uses the 9v rail. You'll first have to check if you get 15v into your A-board, if you do, you'll have to follow along with the schematic and see where the DC-DC conversion takes place and start from there....might be tedious since it's all SMD and the board is huge. I got lucky and didn't have to do that. You might even have to jump-start the PSU to test it like I did.

[Fisher77]

Re: Panasonic TH-42PY80 plasma 10 blink error code

Thanks Dannyx. I just checked, and am deffinitely getting 15v to the A boards A6 connector.

[Dannyx]

Re: Panasonic TH-42PY80 plasma 10 blink error code

Thanks Dannyx. I just checked, and am deffinitely getting 15v to the A boards A6 connector.

Something's busted on the A-board then...most likely the tuner from what I've read. You'll need to track down the 15v signal to each of the DC-DC converters and check them. When all's said and done, you might have to replace the whole board :|

[Fisher77]

Re: Panasonic TH-42PY80 plasma 10 blink error code

Thanks Dannyx. I found one of the MP1415DS regulators was only putting out a little over 1vdc. The one next to it was putting out 9vdc. After being supplied with 14vdc for a bit the regulator made a nice sizzling sound and went dead. Note it was getting warm before it went sizzle. If I can find one, I will replace it and see what happens. They are obsolete now. Another option may be the MP1410ES. I will get back when I get something installed.

[Dannyx]

Re: Panasonic TH-42PY80 plasma 10 blink error code

Thanks Dannyx. I found one of the MP1415DS regulators was only putting out a little over 1vdc. The one next to it was putting out 9vdc. After being supplied with 14vdc for a bit the regulator made a nice sizzling sound and went dead. Note it was getting warm before it went sizzle. If I can find one, I will replace it and see what happens. They are obsolete now. Another option may be the MP1410ES. I will get back when I get something installed.

Another thing I did when I had a dead 3.3v regulator on another board (doesn't matter what it's for or what brand it is) and couldn't find the exact replacement, was I took a standard TO-220 3.3v regulator and botch-wired that onto the appropriate pins on the board just to see if it at least comes on. After all, all you need is GND, IN and OUT. If you can't find a regulator for the exact voltage required, though they should be standard, you can always use an LM317 and tune it to whatever voltage you need. That regulator going up in smoke might not necessarily mean that the regulator itself was bad - some other component it powers could very well be short-circuit or pulling an abnormally high current.

[Fisher77]

Re: Panasonic TH-42PY80 plasma 10 blink error code

I have some LM317's on hand. I also have LM7805's. I could bodge one in if it doesn't draw more amps than the 7805 can handle. Thoughts?

[Dannyx]

Re: Panasonic TH-42PY80 plasma 10 blink error code

I have some LM317's on hand. I also have LM7805's. I could bodge one in if it doesn't draw more amps than the 7805 can handle. Thoughts?

The choice of regulator will be determined by what voltage that rail is supposed to output - the schematic should clearly show this. If it's 5v, then go with the 7805 and see what happens. If its output still goes down when you turn it on, there's a short somewhere after the regulator. Check the datasheet for the original part to see how much current it can source and compare that to the replacement one - must be equal or higher or else the output will drop more and more as the capsule heats up, eventually smoking up.

[Fisher77]

Re: Panasonic TH-42PY80 plasma 10 blink error code

Found the the short. It was the diode in the pic. I finally just fed 5vdc from me bench top power supply. Felt around the board till I discoverd the diode was hot. powered off and let it cool down. Hit it with the freeze spray, power the supply back on, and the ice on this from the freeze spray melted instantly. Pulled it off the board, short gone.

Bands are Brown, yellow, green. I assume this is a zener. I do not see a value on the schematic for it. Any idea on the value?

[vinceroger69]

Re: Panasonic TH-42PY80 plasma 10 blink error code

maybe this
http://www.marsport.org.uk/smd/sod80.htm
RLZ6.8B Brown Yellow Green
Rohm LL-34 package Zener Diodes RLZ Series

https://cdn.badcaps-static.com/pdfs/...0d4628b30f.pdf

[Dannyx]

Re: Panasonic TH-42PY80 plasma 10 blink error code

Found the the short. It was the diode in the pic. I finally just fed 5vdc from me bench top power supply. Felt around the board till I discoverd the diode was hot. powered off and let it cool down. Hit it with the freeze spray, power the supply back on, and the ice on this from the freeze spray melted instantly. Pulled it off the board, short gone.

Bands are Brown, yellow, green. I assume this is a zener. I do not see a value on the schematic for it. Any idea on the value?

I assume you checked the diode off the board and you get continuity in either direction, in which case it's indeed shorted. The schematic should tell you if it's a zener or a regular diode. If it's a zener, it's most likely used as a shunt regulator to ensure that rail doesn't go beyond its designated voltage - I assume 5v in your case. Find it in the schematic first, then towards the end of the manual there should be a list of all the codes of the parts used in the diagrams and their actual values so it's just a matter of finding the code of your diode