On Oct 5, 10:46*pm, "Tube Audio" wrote:
[about a TV that goes dark]
I just took the back off and I think I found the vertical output ic.

Would it be LA7838, the vertical deflection circuit with TV / CRT display
drive IC?

Look for solder joints that have visible cracks, especially around
connectors (the CRT tube-base connector for one, and the
wiring connections that go to that circuit board). Look also at the
heavy pins of power semiconductors and capacitors, and
the flyback transformer. Those heavy conductors are
most likely candidates for an insufficient-heat 'cold' solder
joint.

Dark screen can result from filament or screen connections to
the picture tube, or any of the high-voltage parts that generate
the high anode voltage. Intermittent connections are easily probed
with a (for instance) bamboo chopstick if you can open the
set up while it's operating.