[Kenwood] TS-930S ?

[Allan Fritsche]

Hi gang, I am trying to bring back to life
an old TS-930S. This is for an 82 year old
ham friend and the original problem was the
on/off switch was bad. Well indeed it was bad 
and I replaced with parts from Kenwood.
Rig will power up, receive is OK, transmit
power is a little low, like 80 watts on 20 M.
But the big problem was no display. This 
morning I flipped it over to look at the bottom
side and while moving wires around, behold the display
started working. I loosened and retighten all the
screws and dexoit some of the connectors. It seemed
like all is well so I put the lower case back on
and flipped it over. The display lasted about 1 minute
then went blank again. My biggest problem is that I have
no service manual or even a schematic. It's got to be a 
bad solder joint or corroded connection.
Can anyone tell me the area of the main board I should zero
in on with the radio upside down and the kanobs facing me.
Thanks in advance
Al
W5ADF