Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > Flat Panels & Digital Format

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #1  
Old 11-02-2016, 02:34 PM
pac.attack76's Avatar
pac.attack76 pac.attack76 is offline
Stuck in the past!
 
Join Date: Mar 2013
Location: Song of the south
Posts: 831
Philips 47PFL3603D/F7 no video

Chassis #LC8. 1U LA
Power Supply # 272217100571
bought this 47" lcd yesterday for $30 with the information that the set had to be turned on and off 2 or 3 times to get working which seemed to lean towards a flaky power button. Had nothing to do b with that as the same happened with the remote. Some times it would take a bit to get it to light up. Had it running for 30 minutes while updating my ps3 and the screen went black. Sound only. After that. Re powering would only quick flash and back off with still only audio. Tried again late last night and there was a rapid relay click a few times and a light hiss and now no power. Going to remove the power board today for some testing. What could I expect from this. Easy fix?
Attached Images
File Type: jpg 20161102_125110.jpg (28.0 KB, 16 views)
File Type: jpg 20161102_125225.jpg (42.4 KB, 14 views)
File Type: jpg 20161102_125251.jpg (20.1 KB, 11 views)
__________________
cedmagic.com
Reply With Quote
  #2  
Old 11-02-2016, 05:43 PM
pac.attack76's Avatar
pac.attack76 pac.attack76 is offline
Stuck in the past!
 
Join Date: Mar 2013
Location: Song of the south
Posts: 831
So far, this is what I've come up with. Two large caps circled in red have bulged. As a result, the fuse circled in red is blown. Caps are 450 WV 150 uf. Keep in mind, these pics are not from my set and my caps are swollen and deformed. I could see what looked like leakage as well. Does anyone have a couple of these they could spare?
Attached Images
File Type: jpg Studio_20161102_163205.jpg (125.6 KB, 31 views)
File Type: jpg Studio_20161102_163355.jpg (121.3 KB, 23 views)
__________________
cedmagic.com
Reply With Quote
  #3  
Old 11-03-2016, 08:40 AM
CoogarXR's Avatar
CoogarXR CoogarXR is offline
VideoKarma Member
 
Join Date: Feb 2011
Posts: 610
You can't see it in that picture, but in the corner of that board there is a transformer for the CCFL inverter. Check the posts for cold solder joints. If that's not your problem, it will be eventually. I used to work on that model all the time, and when those solder joints fail, it will arc so bad, some times the board catches fire. I saw badly burned boards several times in that model and the 7603.

It's been a few years since I have worked on one, but I don't remember those big caps being a problem. Those plastic discs appear to bulge sometimes, but the caps themselves aren't bulged underneath. You can take that plastic disc off the top of the cap and look without hurting anything.

I know the Philips/Magnavox of that era did have bad caps, but it usually wasn't the big ones. It was usually the 1000uf, 2200uf, 220uf, etc, medium-sized ones.
Reply With Quote
  #4  
Old 11-03-2016, 01:18 PM
Electronic M's Avatar
Electronic M Electronic M is offline
M is for Memory
 
Join Date: Jan 2011
Location: Pewaukee/Delafield Wi
Posts: 8,921
Might want to check the diode bridge that feeds those big 'spensive caps before you change them...
__________________
Tom C.

What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4

Reading between the scan lines since the mid 2000's.
Reply With Quote
  #5  
Old 11-03-2016, 01:19 PM
pac.attack76's Avatar
pac.attack76 pac.attack76 is offline
Stuck in the past!
 
Join Date: Mar 2013
Location: Song of the south
Posts: 831
Quote:
Originally Posted by CoogarXR View Post
You can't see it in that picture, but in the corner of that board there is a transformer for the CCFL inverter. Check the posts for cold solder joints. If that's not your problem, it will be eventually. I used to work on that model all the time, and when those solder joints fail, it will arc so bad, some times the board catches fire. I saw badly burned boards several times in that model and the 7603.

It's been a few years since I have worked on one, but I don't remember those big caps being a problem. Those plastic discs appear to bulge sometimes, but the caps themselves aren't bulged underneath. You can take that plastic disc off the top of the cap and look without hurting anything.

I know the Philips/Magnavox of that era did have bad caps, but it usually wasn't the big ones. It was usually the 1000uf, 2200uf, 220uf, etc, medium-sized ones.
Unfortunately, those two large ones failed. Very low readings on both, bottom bulging as well as top. They even messed up the plastic rear panel for the tv but you can't see it with out close examination. One of v the c as rattles when you shake it. I'll check the transformer as well. All my other caps look good.
__________________
cedmagic.com
Reply With Quote
Audiokarma
  #6  
Old 11-03-2016, 01:21 PM
pac.attack76's Avatar
pac.attack76 pac.attack76 is offline
Stuck in the past!
 
Join Date: Mar 2013
Location: Song of the south
Posts: 831
Quote:
Originally Posted by Electronic M View Post
Might want to check the diode bridge that feeds those big 'spensive caps before you change them...
I believe it was checked but I'll find out.
__________________
cedmagic.com
Reply With Quote
  #7  
Old 11-04-2016, 12:36 PM
pac.attack76's Avatar
pac.attack76 pac.attack76 is offline
Stuck in the past!
 
Join Date: Mar 2013
Location: Song of the south
Posts: 831
Where's the diode bridge on this? Also, is the are mentioned earlier which is prone to arc in the top left corner?
Attached Images
File Type: jpg Studio_20161104_113712.jpg (123.5 KB, 18 views)
__________________
cedmagic.com
Reply With Quote
  #8  
Old 11-04-2016, 02:15 PM
Electronic M's Avatar
Electronic M Electronic M is offline
M is for Memory
 
Join Date: Jan 2011
Location: Pewaukee/Delafield Wi
Posts: 8,921
I believe the diode bridge is on the center heatsink...It is likely a 4 leg semiconductor (because who uses discreet diodes anymore?) that feeds gets it's input from the power cord (through some LC filters) and directly feeds those big lytic cans DC. If the bridge is shorted it will feed AC to the new cans and blow them quickly.
__________________
Tom C.

What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4

Reading between the scan lines since the mid 2000's.
Reply With Quote
  #9  
Old 11-04-2016, 02:36 PM
CoogarXR's Avatar
CoogarXR CoogarXR is offline
VideoKarma Member
 
Join Date: Feb 2011
Posts: 610
Quote:
Originally Posted by pac.attack76 View Post
Where's the diode bridge on this? Also, is the are mentioned earlier which is prone to arc in the top left corner?
Yep that transformer circled is the one prone to cold solder joints and arcing.

I just happened to find a pic one online:

Attached Images
File Type: jpg burned.jpg (100.1 KB, 70 views)
Reply With Quote
  #10  
Old 11-05-2016, 12:17 AM
pac.attack76's Avatar
pac.attack76 pac.attack76 is offline
Stuck in the past!
 
Join Date: Mar 2013
Location: Song of the south
Posts: 831
Does the bridge have to be de-soldered to test? The transformer connections look good. Found two caps for $8. Is that a good price? They appear to be a brand called Negetive. Never heard of them.
__________________
cedmagic.com
Reply With Quote
Audiokarma
  #11  
Old 11-17-2016, 01:06 AM
pac.attack76's Avatar
pac.attack76 pac.attack76 is offline
Stuck in the past!
 
Join Date: Mar 2013
Location: Song of the south
Posts: 831
i want to check that bridge before i put new caps in. does it need to be pulled to test? what brands of caps are recommended? i dont want to use cheap caps and Radio Shack is out of the question.
__________________
cedmagic.com
Reply With Quote
  #12  
Old 11-18-2016, 06:15 PM
miniman82's Avatar
miniman82 miniman82 is offline
First Light: 1952-2011
 
Join Date: Jun 2009
Location: Great Mills, MD
Posts: 4,073
Not usually, just use your DMM in diode test mode to go through the 4 internal diodes.
__________________
Evolution...
Reply With Quote
  #13  
Old 11-20-2016, 11:56 AM
pac.attack76's Avatar
pac.attack76 pac.attack76 is offline
Stuck in the past!
 
Join Date: Mar 2013
Location: Song of the south
Posts: 831
What reading should I get?
__________________
cedmagic.com
Reply With Quote
  #14  
Old 11-25-2016, 07:51 PM
pac.attack76's Avatar
pac.attack76 pac.attack76 is offline
Stuck in the past!
 
Join Date: Mar 2013
Location: Song of the south
Posts: 831
Quote:
Originally Posted by miniman82 View Post
Not usually, just use your DMM in diode test mode to go through the 4 internal diodes.
What should they read if it's good?
__________________
cedmagic.com
Reply With Quote
  #15  
Old 11-25-2016, 11:14 PM
Findm-Keepm's Avatar
Findm-Keepm Findm-Keepm is offline
Followin' the Rules...
 
Join Date: Jun 2007
Posts: 2,835
With the DMM on the diode scale, you should place the negative lead (black lead) on the + lead of the bridge - that is where two cathodes are connected. Then place the red lead on one of the AC leads of the bridge (may be marked with a sinewave) - you should see the forward voltage drop of the diode, anywhere from 0.45V-0.7V. Then move the red lead from your DMM to the other AC lead on the bridge rectifier - and look for the same.

To test the other two diodes, place the red lead of your DMM on the negative lead (-) of the bridge - two Anodes are connected there. Then, alternate between the two AC leads of the bridge, again looking for the 0.45-0.7V voltage drop across the diodes. Any lower than 0.45V reading,and you've got a shorted diode in the bridge.

Youtube? https://www.youtube.com/watch?v=50Cwo3Of288

Hope this helps...
__________________
Brian
USN RET (Avionics / Cal)
CET- Consumer Repair and Avionics ('88)
"Capacitor Cosmetologist since '79"

When fuses go to work, they quit!
Reply With Quote
Audiokarma
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 04:35 PM.



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
ęCopyright 2012 VideoKarma.org, All rights reserved.