On Thu, 26 Feb 2009 21:27:58 -0600, Steve put finger to
keyboard and composed:

I have a Sharp LC-15SH7U that took a power surge & went dead. After
fixing a shorted zener diode in the 33V power supply & a shorted dual
fet in the backlight inverter the tv powers up just fine & has a
normal picture but now the top six buttons don't work properly.
Power works properly
Menu, Input, & Volume Down don't work at all.
Volume Up works as Volume Down.
Channel Down works as Volume Up.
Channel Up works as Channel Down.
Button order is Menu, Vol down, Vol up, Chn down, Chn up, Input,
Power.

It has a four wire interface to the main board. I haven't traced the
circuit out yet, but a quick glance shows all switches are connected
to pin 1. I imagine the other three pins work a set of buttons each,
but I'm not sure. Is this a common configuration for Sharp TV's? I
haven't been able to find any service info for this TV, so I'm sure
I'll have to start tracing.

Thanks for any help,
Steve

I have seen the following technique used in corded VCR remote
controls:

SW1 SW2 SW3 SW4
_|_ _|_ _|_ _|_
| | | | | | | |
GND o-- R1 --o-- R2 --o-- R3 ---o-- R4 ---|
|
SW o-------------------------------------|

The resistors could be binary weighted, ie R, 2R, 4R, 8R.

I can't see how this scheme fits in with your setup, though.

- Franc Zabkar
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