I like this solution.
I can't quite see what is printed on your unit but it seems to be an
SOT-89 type package. I can't find any 7809 units in that configuration.
I can find them in the D2pak or the to252-3 style. I assume either of
those would work as well?
You say you used a 70L09 but aren't those only rated to about 100ma?
That wouldn't seem to be high enough to handle heavy loads from the
2822.
tim ab0wr
On Wed, 07 Mar 2018 18:01:05 +0530
"Raj vu2zap" <rajendrakumargg@...> wrote:
Solution 3: 78L09. the center lead looks soldered but it is floating
but the tab is soldered to the copper below it. The white wire is my
fix for prevent the filter relays from clicking during PTT. Yes the
board needs a brush cleaning!
The audio is fine but distorts at high volume. The 9V voltage out
does not drop at max volume.
Emacs!
At 06-03-18, you wrote:
I did some experiments with the chip failure.
FCI chips were sourced locally and plugged in. No failure with
normal volume. I raised the volume to a high level and the chip
failed immediately!
Solutions
1: Add a resistor in series with the 12V line maybe 10-15 ohms to
drop the voltage.
2. Simple solution is to use only a 16 Ohm speaker or add a series
8-10 Ohm resistor with the 8 ohm speakers.
3. Cut the power track to the TDA and insert a 78L08 or 9 to reduce
the voltage. There is a track which can be cut
and a SMD or leaded regulator can be soldered on the board. This
track leads directly to the chip and filter cap.
The second solution may be the simplest.
Further experimentation scheduled for tomorrow!
