Is it only column 7 that is having issues when you say the sword lights are not working or is it ALL the lights in the sword (some lights in columns 6, 7 and 8)? What about the other lights in column 6 and 8, do they fade out too?

The SCRs are in the row circuit - seems unlikely they would be the cause of a column issue.

How about replacing IC10? Is it socketed (could be an easy thing to test if it is)? Have you watched pin 16 on IC10 to see if it stops pulsing? Compare it's wave or pulse signature to the other columns? Could be a weak/slow output on the PIA. Is it an AMI chip by chance?

OK, thanks. So column 2 works normally and the others eventually fade away.

Use your scope to look at the output of IC10 for Column 2 and compare it to column 7 to see if there is a difference before and after fading.

Sounds like a solid plan. The Motorola PIAs are good in the reliability department whereas the AMI versions fail a lot more frequently. That is the only reason I mentioned it.

Congratulations on the fix!

Do yourself a favor and throw away the sponge that came with your soldering iron. Use a metal mesh type cleaner to keep the soldering iron tip clean. You run much less chance of wrecking the tip of your iron using the metal mesh type. https://www.amazon.com/Soldering-Iron-Tip-Cleaner-Black/dp/B00J66FSY2/ref=sr_1_11