DIYbanter - View Single Post - Sanyo AVM-2554 Tuner Problems

[email protected]

wrote:
Okay, this is me attempting to fix a TV when I probably should just go
buy a new one...but I'm an engineer, which means I'm cheap and I think
I can fix anything.

When I change the channel (with the remote or from the tv itself) the
digital number telling me what channel I'm on changes. But the channel
doesn't change (i.e. I'm still watching 5 even if I try to change to 6
even though the digital number says 6). Sometimes, it will eventually
change itself, but not often. To me, this clearly points to the tuner.
I've pulled out the main circuit to see if any solders looked bad that
I could re-solder, but nothing stood out to me. Is this even worth
attempting to fix, or should I just buy a new one?

Thanks,
David

Couple of possibilities, it is an older set so I haven't seen one in a
long time.

Open resistor on the 33V line. They use the regulated 120V source
through a resistor to a zener and capacitor to supply the tuner with
the 33V for the tuning voltage.

The tuner itself may have bad solder connections, especially to the
ground structure. Be very careful to use proper grounding of your iron
tip and yourself and care with the tight surface mount components if
you get inside the tuner to examine and repair any connections.