no +28VDC on main power supply on R87

[shrimpeater]

Supply board that has 3 led lights. I'm not getting anything on the +28 VDC. I have changed boards and everything is good. 
This board seems to be servicable with only a few componites. 
I'm waiting on a manuel hoping it has schematics so I can trouble shoot the board and make a reapir as needed. 
I'll be changing caps on both boards because of thier age. 
Is there anything I can look at that might be causing this problem. 

[jukenorman]

I only have a crappy pdf manual of the R87 but there's no schematic of the power supply, maybe you will have better luck. If you have a working circuit board with only a few components, you might already be halfway there!

Norman.