Hi I took a look at your pictures. Very hard to tell if there is a wrong connection or not. But even harder to tell – if not impossible – if there are not any shorts between the pins. The soldering looks a bit suboptimal as far as I can tell.
Take a multimeter and check all the connections for continuity and make sure adjacent pins are not connected. If necessary use a solder pump to remove all the solder and start again. There seems to be quite a bit too much solder on the pins.
From what you describe there might be a fundamental problem. Check all the voltages (-5, +5, -15 and +15). Are the LEDs and buttons on the front panel working?
I’m a very beginner solderer, but I did check for continuity, and most of my links seem good.
Please make sure all of the connections are good..
Here are my questions:
1) I ‘think’ I have the new board model, but if not, that would explain the problem. There is a small board connected to my 366, but it doesn’t say 396 anywhere on it, and from what I can tell the connections look different from that shown in the picture of 396 in the Tubbutec construction manual. I don’t think I messed this up, but if I did it would explain a lot.
It seems to be the new board model. The additional board is probably a midi retrofit, maybe the CHD?
2) I had a lot of difficulty soldering to the IC 30 chip, and had to redo it several times because the solder smeared along all many of the top connections (I need a smaller soldering iron) and I worry if I may have fried the chip (or another component along the way). How would I know?
Hard to tell from pictures alone. You’d probably need an oscilloscope to see if the chip is still working correctly.