The connections that give the most trouble are the grounds both around the board perimeter, and the posts that poke through the pc. There's not a lot of ground redundancy in those tuners, so a single ground connection will cause problems. Deflux the board till it shines, get a bright light, use magnification, and reflow the board again. Don't overlook the small can coil connections.


On Tuesday, December 11, 2012 11:52:50 PM UTC-5, David Farber wrote:
David Farber wrote:

John-Del wrote:

On Tuesday, December 11, 2012 4:10:49 AM UTC-5, David Farber wrote:

I hit the



switch button again and the problem still stayed with the smaller

window.



The Sonys of that era used two tuners for main and pip, but didn't

swap the video between large and small windows, but swapped the

channel instructions for each tuner as the swap button was pushed.

That's why the problem stays with the particular screen window.



Those tuners were combo tuner and IF, and are known to have issues

with grounds and bad connections on coils. You can replace the pip

tuner if you can find one, or pull it and resolder. Some of those

TVs in that era used double sided boards, and require a decent

technique to pull the tuner (green boards). If it has the brown

board, it's an easy pull. BTW, although the tuners look identical

but they're not, so make sure to identify the correct one by pulling

the RF input lead off each tuner to confirm the pip goes to snow.



Hi John,



Knowing that the channel instructions are swapped instead of the

tuners does make this job easier. I'll be sure to mark the bad one

before I pull it.

Thanks for your reply.



I pulled out the tuner and resoldered it. There was nothing out of the

ordinary that I saw. A few of the connections were beginning to crack but

nothing I saw that would have caused a failure. Anyway, I put it all back

together and it's still going to snow at channels 48 and above.



--

David Farber

Los Osos, CA