TH79 won't turn on

[KC8GKH]

Help!  My Kenwood TH79A that is barely used won't turn on.  It's not the battery (doesn't work with a good one & doesn't work when plugged into adapter).  For the first time in its life, I took off the back cover.  Nothing is loose.  I put it back together, tapped the edge of it a couple of times on the countertop, it beeped on and the display works.  I've turned it off and on a few times and it's still working.  Last year (the last time I used it), I had to hit the edge of it in my hand and it would turn on.

Suggestions?  Sound familiar to anyone?

It needs to be reliable for me...

Repair place suggestions?  Any idea on what may be wrong and costs associated with it?

Thanks!

[N8HHS]

i had same problem and after hours of trouble shooting
i found that the on/off vol. control had broken loose
the contacts are a circuit board that push thru main
board. good luck. 73's N8HHS