Found these inside a non-working 71B

[MikeSD]

Gonna stop for a day and think about this.

I decided to put the RAM in it's final place. Was working good tacked onto the top of one of the RAMs. You can see white wires in the photo above, on right.

Put it in the final place, soldered everything in, tucked the wires away. Looking pretty good. Then I powered it up, and checked the 32K RAMS. Still working great.

But dang! One of the 4K mem chips wasn't configuring now. Total RAM 80,xxx. Wonder if it's the one I was tacked onto. Generally the last thing you touch is where the problem is. I have verified it's the 0.03 bank that won't configure. I can FREE and Claim ports 0-2 but not 3. I need to find a layout so I know which RAM is 0.03. I have lots of 4K RAM, so replacing it, if dead, isn't a problem. But I think it's just a bridge, or bad solder of something I just touched.

I was tacked onto the top RAM (back right) in the photo above.

What Ref is that? And which bank is it? The only 2 devices I touched are the on back right in the photo above, and the back left (Math), in the photo above. No other RAMs were touched.