Greetings,
Looking for some experience before I start shot-gunning parts. I have a wpt that is missing lamp column 3. I get continuity from J13 pin 7 all the way through the harness to the sockets with no shorts to ground. The "collector" tab (I know it's not that anymore) in figure 1 shows a steady 18v on U15 and all others regardless of test state. The top leg of the U15 in figure 2 shows 15+ volts only on U15 regardless of the test state. On all the other ones it fluctuates at a much lower voltage as the lamps flash when i test all in lamps mode or their respective columns modes. I'm thinking that U15 is shorted internally. Does anyone have experience with this?

WPT U15 fig. 1 (resized).jpg

WPT U15 fig. 2 (resized).jpg