Panasonic Touch Button

[maxm]

I'm [attempting to] fix this "space age" Panasonic TV for a friend, and have gotten it mostly working except for the "touch pad" power button. This is the first set I've seen with this, the power is controlled by a touch pad, not a physical switch or button. I didn't even know they had this technology in the early 70s when this set was made, but they didn't seem to have it perfected at the time.

Most of the time, when the set is plugged in, it will turn on. When the power button is touched, the picture will dim slightly and get smaller. I assume the the set is getting a little less power. Touching the button again returns the picture to normal. If you puch it on and off enough, you can get the set to almost turn off, with a very din small picture and almost no sound, but if you push the button again to turn it on, the picture will only get a little brighter and expand slightly. If you unplug the set and plug it back in, you are back at the beginning. Once I was able to get the button to turn the set fully off and on, but then it started to do what it does now again.

I don't have a schematic for the set, and have no idea how the touch button works (I still don't understand those touch lamps ). There is a small circut board that I assume controls the touch button as there is a wire leading from the board to the button. There are no relays in the set, so I assume it cuts the power some other way. Could it be a bad diode or voltage regulator?

I attached a photo of the control board and the front of the set, you can see the button as the silver rectangle over the three small knobs. The set is Model TR-542.

Thanks for any help!