Quoted from Bakerman:All of the above, then when I have an issue like this (short on data or adress bus, or loading of a line on a bus), I make a list of all the chips involved, and, one at a time, snip the relevent chip leg (D3 in your case). Then measure to see if the short or load has gone. The trick is to not snip the leg at the chip package, but half way down the leg. In this way a little blob of solder can be used to remake the connection after you have found the faulty chip.
Takes a little time but I have done it on many boards when there is no other choice, and is better than removing whole chips.
P.S. Remove socketed chips on the bus first of course!
I thought this might be an option! Glad to hear like it sounds a possibility, will definitely be a lot quicker than desoldering chips until I get to the culprit.
As for the "funky" stuff -- one solenoid locked on, an array of controlled lamps locked on and not strobing. Has an awful hum from the sound board too, but I think that is unrelated, but who knows, it could be dragging the data line low across the whole system and could knock that out too. But, I think that is more likely a bad joint on the DCS caps.
