tv stopped working.. - Page 2 - Videokarma.org TV - Video

aidynphoenix · #16 08-31-2010, 12:03 PM

ok i replaced the cap..
it still does the same thing..
ok there is a big heatsink near that cap has u4501 VERT engraved on it..
the black chip thinggy cliped onto it is labled. LA7831. than below that 51105 than below that.. 01a 0b4 (thats all on the chip)

im guessing that is the vertical IC>>??

should i just buy something labled la7831.. or can sombody find me a link to a site selling one?

aidynphoenix · #17 08-31-2010, 03:49 PM

if interested.. the cap i replaced was the one leaking.. a 100uf 20v. i replaced it with a 100v 50v
the old one was flat on the top, but the bottom was buldging and leaking orangeish brown stuff

aidynphoenix · #18 08-31-2010, 04:14 PM

i seem to be finding that part on websites but only for sayno and philips televisions.. does that make a difference?
i found this on mouser. they seem to have something called cross reference part.

http://www.mouser.com/Search/Refine.aspx?Keyword=LA7831
is that like a compatiable replacement?

mbates14 · #19 08-31-2010, 07:56 PM

Yup. looks like a CTC167 to me. I had a floor model CTC167 that was bought from steinbergs before they went out of business.

I had to change darn near 80% of all the caps before it sprung back to life. out of those 80%, maybe about 50% had crud/leakage around the pins. Then the tube wore out and i junked it.

It started as vertical foldover that would go away after a slow period. then eventually to collapse, and loss of HV.

aidynphoenix · #20 08-31-2010, 09:03 PM

Quote:

Originally Posted by mbates14

Yup. looks like a CTC167 to me. I had a floor model CTC167 that was bought from steinbergs before they went out of business.

I had to change darn near 80% of all the caps before it sprung back to life. out of those 80%, maybe about 50% had crud/leakage around the pins. Then the tube wore out and i junked it.

It started as vertical foldover that would go away after a slow period. then eventually to collapse, and loss of HV.

thanks for this info i will replace all of the other caps soon

mbates14 · #21 08-31-2010, 10:01 PM

if your going to use this TV as a daily watcher, it might be worth just recapping it as if you were doing a 50s era TV.

its getting old. caps dont last forever.

aidynphoenix · #22 08-31-2010, 10:15 PM

anybody kno where i should buy the proper IC?>

Findm-Keepm · #23 09-01-2010, 08:17 AM

The vertical IC is mounted on the U-shaped heatsink closest to the CRT - picture 1271.jpg shows it to the right. The part number is on the chip, and starts with LA.... the whole six letters and numbers are the part number, something like LA7830, LA7838 or the like. Do a Google Shopping search to find a replacement - the LA7830 (which I think it might be) is only a couple of bucks from some dealers.

Cheers,

aidynphoenix · #24 09-01-2010, 04:23 PM

ok so im planning on ordering this tonight
http://www.bdent.com/ProductDetails....A7831&CartID=1

although google search didnt come up with this site.. most of the other sites had a minimum purchase i had to spend.. something like $50.
this one is a $12 minimum.. the IC is only $7.23 so i will order the caps needed at the same time to make up the difference..

is it important at all or could it benifit from a good cleaning?

aidynphoenix · #25 09-09-2010, 11:38 AM

ok i have all the caps and the IC..
now i noticed something new now..
on the main board near the powersupply area i see a circular disc about the thickness of a nickel but the legnth of a dime, that is disconnected on each end just kinda hanging out..
almost like a ceramic cap with no shell on it..
its grey and has 100-01a a170 1 written on it..

following the traces that connect to it. i can see it connects to a relay (i think) and a empty terminal marked degauss
i can see that its not used (i think) unless you are degaussing the television..
should i just solder it back in place and leave it alone?

any idea what this part is? should i just try and solder it back together or does it need to be replaced?

aidynphoenix · #26 09-09-2010, 11:48 AM

oh wait it actually runs into the ground wire attached to the springs that go around the outisde of the tv..
think when i discharged the television maybe it poped that component?

aidynphoenix · #27 09-09-2010, 12:26 PM

crap.. i replaced the IC., and most of the caps and still have the same exact problem..
it still has the thin line across the middle..

anything else i should check guys?

btw i put alittle drop of solder on each end of that component that came loose and reattached it.

radiotvnut · #28 09-09-2010, 12:49 PM

When the original IC shorted, it likely took out a small value resistor and possibly the B+ diode that provides B+ to the IC. This voltage source comes from the flyback transformer.

miniman82 · #29 09-09-2010, 01:00 PM

Didn't read the whole thread, have you ohm'd out the yoke?

aidynphoenix · #30 09-09-2010, 02:44 PM

ohm'd out the yoke??

thanks much for the replys.
ok so most likley i need to replace those components..
i know how to check resistors.. but how do i check a diode, or should i just follow the trace from the b+ to a diode?

now without a schmatic.. is there a way i can find out what kind of diode it is or would any more beefy diode work in place?

im going to take it back apart now and take a closer look