tv stopped working..

[aidynphoenix]

ok so with it open just visually i think i might of have found the bad components..
i labled the points of interest as 1,2,3 1 is a resistor that looks strangely dark on one end, and 2 is the cap that was leaking that i have replaced already. and 3 is what looks like a very dirty diode..

[aidynphoenix]

uh oh. i found another cap while staring at this that is leaking pretty good..
i hope this doesent mean i need to buy another vertical IC now??


btw i cleaned off that dirty diode and it looks the same as the others.. it was just covered in cap juice.


why do all these caps leak out the bottom instead of buldge at the top like i usually find them?

[aidynphoenix]

ok so i found the bad resistor, and learned how to test diodes,, (sorta) the website explained, as i understood it, that you should get a reading in one direction but not in the other direction..
it didnt clarify weather a bad one would be open both ways, or weather impendence would rise or drop when you are dealing with a bad one....
im looking in my box o parts for another resistor to replace this one..
by looking at it very carefully it looks like the colors are black-black-gold-gold
now it cant start with black and it also has a tiny bit of brown near the edge of the black also on one side it looks like the 2nd ring might of have been a white or grey..
if grey 1.8ohms if white 1.9ohms
is one of these gambles safer than the other?
or does it need to be exact??

[aidynphoenix]

ok i found a resistor at a really really close resistance.. if not the exact..
the color code is brown-grey-gold-gold.. so 1.8ohms

[aidynphoenix]

WHOOOOO ok its working again. now just to be safe before i put this tv in fulltime use...
i am going to do more recapping.. sofar there has been 3 caps leaking blackish stuff from there bottoms.

also about that resistor i installed..
im pretty confident the origional resistor colors were either
brown-white-gold gold (1.9) or
Brown-grey-gold gold.. (1.8)
the difference is .1ohms..

how important is it that it is EXACTIALLY the same resistance??
what i put in there is a Brown-Grey-gold-gold (1.8ohm)

is it mostlikley the Vertical IC would run hotter than normal?
or maybe that the screen might not streach to be the full vertical size?

[radiotvnut]

It should not make any difference. That resistor is only there for safety reasons. It is designed to open, should an excessive load take place on the B+ line feeding the vertical output circuit.

I've seen several of these sets where the caps would leak and eat the foil off the PC board. RCA and Mitsubishi must have been getting their caps from the same supplier. No, wait, I think the caps in Mitsubishi sets were much worse.

[aidynphoenix]

Wow good to know.. reason being in the areas where the caps were leaking there are tiny black bubble like formations forming on the foil underside the board..
think i should maybe run a wire from point to point bridging those traces affected??

also thanks a whole lot Radiotvnut, and also the other people who helped me before.
im happy to get this tv in our livingroom.
our current tv is a little 17"
its hard to see whats going on in some movies and also play on a split screen in videogames...

this tv is a 26" so its great compared to the other..

i think the thing that i like the most about this little project. is that i learned alot..
this is the first project where i actually found caps leaking from the bottom instead of the caps buldging at the tops..
also i didnt know about the leaking caps eating away at the traces..
(btw the leaking caps were all 105c Nichicon) each was a different uf rating, first one was a 100uf 25v, second was a 220uf 35v and third was a 470uf 16v

[aidynphoenix]

does anybody know why some caps leak at the bottom and some buldge?
is one related to heat over time, and the other high voltage for too long or something like that?

[mbates14]

well if you want to keep the set running, and if its sentimental to you in any way to make it worthwhile, i would replace ALL electrolytics.

[Zenith26kc20]

you may want to google "capacitor plague". It will explain a lot about the drooling capacitors.
Also, do keep an eye on your soldering iron tip. Usually the oil left by the caps on the board will eat the tip rapidly!
The worst I ever saw for electrolytic problems were Mitsubishi 36 inchers. The would have two and three inch areas of foil turning black when some of their caps drooled.

[holmesuser01]

I've noticed how manufacturers like to put capacitors close to heat sinks and nice warm wirewound resistors. Often, they just get cooked and fail.

I have a 1991 Sony 27" that used to eat the big regulator IC regularly, about once a year or so. It got so bad, that I now keep a spare IC when I buy them in stock for this set.

The last time I did the repair, I installed a 3" box fan that blows air across the IC and its heat sink. It's a 220 volt fan running on 120 volts, so it runs really quiet. I dont notice any noise from the set. It's been almost 3 years, and the IC is happy.

[mbates14]

well ive come to learn that engineers dont give a hoot. They just engineer the crap. they dont have to worry about fixing it.

if they had to fix what they engineered, the electronics world would be 180 of what it is today.

Example: if you ever have to service a 5 disc CD changer trayload mechanism from Panasonic, such as the SA-PM19 or SA-pm29, or SA-PM33, etc etc etc... DONT.. BE WARNED.

I tore it apart and retimed it 3 times already, and still the timing isnt correct and jams at the trays. There are timing marks and holes all over the thing, but the service assembly manual being in broken English does NOT help matters any at all.

[aidynphoenix]

well its almostly completely recapped, i recapped all the ones near heatsinks and most of the other ones, i left some of them alone because of the locations,..
i had to adjust the brightness, i must of have bumped it when working on it.
this set has a great picture.