Thanks, all.
Borrowing a second scope may not be possible at the moment, my source for the scope hasn't got another that can leave the building except to go to a cal lab.
But there is the possibility for me to budget for a cheap used scope, say ~$100. Checking Craigslist for my local area shows some in the range, e.g., BK Precision model 2120 (kind of far away), EICO 460S (possibly really inexpensive), Heathkit 5mhz with a Heathkit multimeter of the same vintage, all documentation, and extras for $125 (looks very clean and is and conveniently nearby).
So if that was the case, what would be the minimum spec scope I would need to troubleshoot this problem? Or should I just buy one of those cheap disposable single-channel MP3 player sized DSOs and sell that later after making the repair (or just keep it and use as a fancy meter..)? A plus for this concept is future storage space - my electronics workspace is a bit on the small side.
I will take the advice to avoid the high-voltage areas seriously, I have a healthy respect for electricity.
Note that this will be a real challenge for me - I know almost nothing of electronics, this will be a true learning experience for me and I will have to budget time for it as well. But I look forward to it, and will certainly be asking for more guidance after I follow the 'scope tutorial.
Thanks to all for the advice.