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Bought this about 14 mo's ago. Had an occasional problem with it 'rebooting' (eg, turning off/on) but wasn't annoyed enough to do anything. Now a month after the warranty has expired it's begun going in to rebooting convulsions everytime I turn it on. It gets vertical lines and then reboots. Sometimes it emits a loud screach sound (except after I've remembered to lower volume to 0 before turning it off previously). After about every 4 or 5 reboots it turns off. The total number of reboots before it remains on stable has been slowly increasing to now about 15. Once through its convulsions it stays on without any further problems. Magnavox CS has been worthless.


Any thoughts on what this could be? Options to repair? Options to force Magnavox to do something other than say 'sorry'?


Thanks,
 

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Pull the back off and inspect the power supply board for capacitors with bulging tops. If you don't see any then you'll want to try a new Scaler Board .
 

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Quote:
Originally Posted by ebattiston /forum/post/20265729


any luck with this repair? i am having the identical problem however the convulsing has no end

I just fixed a 19MF337B/27 that somebody gave me. The problem was not in the power supply board. It was on the main board.


Remove the base stand (2 screws).

Remove five screws that hold on the back.

Remove the metal cover of the main board (four screws plus the two screw posts next to the VGA connector.

Inspect the electrolytic capacitors on both boards.

Replace any bulged capacitors.


It seems the most common problem is three bulged capXon capacitors on the main board: C112, C117, and C118. The specs on all three of these are:

1000uF, 10V, Z=0.027 mOhms, 105 degF, 25% tolerance, 1.5A ripple current, 2000hr life, 10mm x 14mm.


Replace with caps of suitable specs. A good choice is Panasonic/ECG EEUFR1C102 aka P14398, which has specs:

1000uF, 16V, Z=0.028 mOhms, 105 degF, 20% tolerance, 1.79A ripple current, 8000hr life, 10mm x 16mm. You can get these from digikey.com for $5 delivered by first class mail.


That is what I used, and the set is working fine since I fixed it yesterday.
 

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The above is spot on, I have same tv, same symptoms. Followed the above steps - bingo. Same 3 CAPS are bubled, Replaced with recommended parts and its fixed - Great info -


Thank you
 

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bassman--


I asked a few people who ought to know more than me (on badcaps.net) about the specs of those panasonic caps, and they said that they would be very good.


Hey, you don't have to use ALL CAPS when you type 'caps'.
But I guess I don't have to use all caps when I type 'all caps' either.



Glad it worked for you.
 

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Quote:
Originally Posted by Junkrepair /forum/post/20347717


I just fixed a 19MF337B/27 that somebody gave me. The problem was not in the power supply board. It was on the main board.


It seems the most common problem is three bulged capXon capacitors on the main board: C112, C117, and C118. The specs on all three of these are:

1000uF, 10V, Z=0.027 mOhms, 105 degF, 25% tolerance, 1.5A ripple current, 2000hr life, 10mm x 14mm.


Replace with caps of suitable specs. A good choice is Panasonic/ECG EEUFR1C102 aka P14398, which has specs:

1000uF, 16V, Z=0.028 mOhms, 105 degF, 20% tolerance, 1.79A ripple current, 8000hr life, 10mm x 16mm. You can get these from digikey.com for $5 delivered by first class mail.

I have been using this TV as a VGA monitor for the past six months, leaving it on all the time. Lately the picture has been flickering between normal and a tint with too much cyan. Also I heard some rather loud popping one time when I powered it up. So I opened it again and found that C114 had gone bad---bulged on top. The three caps that I had replaced before are fine. I also read of problems with C175, so I decided to replace it too, even though it looked okay.


The five caps mentioned are exactly the CapXon LZ series caps on the mainboard. The specs are here:

http://www.capxongroup.com/files/2011-LZ%20Series.pdf


C114 8x11.5mm, 330uF, 16V, 1080 mA ripple, 38 mOhms ESR/impedance

C175 8x11.5mm, 470uF, 16V, 1080 mA ripple, 38 mOhms ESR/impedance


At digikey you can easily match all these specs except the physical dimensions.


I used Panasonic/ECG EEU-FR0J122 and EEU-FR0J821, which are bigger than the originals. So I had to tip them on their sides and bend the leads in order to fit them into the faraday box. I hope that that is okay. Anyway it works fine so far. The replacements have 9,000 hr. and 10,000 hr. life specs.


There are also about seven CapXon GF series 100 uF 25V caps on the mainboard. I ordered some spares for these, but did not replace them, because they look fine and I have not heard of them going bad.


In my experience, anybody replacing caps in this TV should replace all five LZ-series caps mentioned above the first time around.
 

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Thank you Junkrepair! I did exactly as you posted and replaced 3 bad caps and guess what? .. the TV works again! I was given this TV by my neighbor who had told me that it just quit working about 10 months after he bought it and then it just sat in his garage for a while. He knows I love electronics and gave it to me and told me if I can fix it, use it, if not, recycle it! Well just so happens I had some caps lying around, a soldering gun, a little time, of course my friend Google, and now I have a nice, working 19" LCD TV!


I appreciate you taking the time to post your solution. Keep up the good work!

 

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I just created my account so that I could thank Junkrepair for giving me the confidence and the information I needed to repair my old Magnavox 19" lcd tv.

For every direct thanks you all get on here, please know that there are probably hundreds of others that just didn't find the time to express their appreciation.

Thank you!
 

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You also should replaced C175 and C114 because you will experience different problems down the road.  It is also important to know that the capacitor voltage is not higher enough that is what is causing them to break down over time. Increase the voltage on these capacitor to 25V instead of 16V
 
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