Fisher Coinstrike Problem, help appreciated.

[SVEN1]

I was given a Fisher Coinstrike control box and 8" search coil. Owner said it would not work.
Here's what I found after inserting two new 9 volt batteries and coil connected.
1) Powers up.
2) All menus can be adjusted. Can switch between All Metal and Disc modes.
3) No audio output
4) Will not detect any metal object.

5) Only when pressing and holding down the Pinpoint button.
a) there is audio output
b) detects metal targets past over the coil in both AM and Disc modes.

Followed the 2 pinpoint keypad traces to the circuit, one goes a n on to the large processor , the other goes HEF4013BT IC.
I don't have schematics.
Not sure if this C$ is fixable due to a program code issue or something else.
Anyone know? Or should this just go into the scrap pile?
Thanks

[ZuMi77]

I would check carefully for any damage that can be detected visually, then replace the damaged component. If not, look for a factory reset button and use it; restoring factory settings could eliminate the problem. If not, I would try to update the software if possible.
Other considerations:
Check the audio amplifier circuit and its connections. You can detect objects in pinpoint mode; it likely uses a separate audio that bypass the main audio amplifier.
So, you may trace and repair the audio amplifier if any damage could be located.

It could also be an issue with the oscillation, in this case it will be more complicated to troubleshoot the problem.

In the end, if the problem persists and nothing can be done about it, I would not scrap it; I would join it to my own museum for future reference.

[kt315]

check all solder point on every components. you need fat glass 10X. oldie boards getting sick that we call 'cold soldering, microcracking'.
research every solder layer between chip pins and solder pads.
wash off the board by 95% spirit before.

[nickel_n]

check the keypad that its not shorting out on one or more keys

[SVEN1]

Thanks, Will look it over and see what I find over the next two weeks.