Smoke on my power amp

Well, I feel so stupid about what I had done.
Anyway, I was trying different preamps, different IC cables, different speaker cables, and different sources (CD/SACD players and phono cartridges). While I was playing around, I got a bit sloppy.
I would still like to have the amp with a built in protection mechanism to prevent such case. It is so harmful to the power amp, but having no built in protection mechanism for $5K amp a decade ago does not sound right.
I cannot find any clear damage from these two inside photos. Any of you see burnt components or circuits? Thanks much.
https://photos.google.com/photo/AF1QipPSt_CM_-03crVgXYW6NBwEgfAXc3eNWuPSAlBJ
https://photos.google.com/photo/AF1QipNIz2uuUz90t-qmUl15mIkIjsxDoqVbj8YsuPLa

Technically, once the blue smoke comes out you need to send it for repair to have the smoke put back in.

Plug your amp to a 'Dim Bulb Tester' to find out if any repair is required.

https://www.youtube.com/watch?v=wRFRwOnLsZI&t=15s

@ihcho The Google Photos links you provided in your last post don’t work, at least for members of the public. I’m not sure how or if photos uploaded to Google Photos can be shared publicly.

If you upload the photos to Google Drive, though, and then select/highlight each of them, one of the icons which will appear at the top of the listing will allow you to create a shareable link.

Regards,
-- Al

first .... there is nothing wrong to run an amp without speakers or only one channel. but disconnect speaker cables from the amp terminals to prevent  speaker wires   accidental short... most new amps has adequate protection , but vintage ones   do not survive .
so you got 2 possibilities... one is the other ends of speaker cables touched each other . or   just bad luck and amp  got fried with no reason whats so ever . now, can you turn on the amp ?preferably not... for one reason  ...to help a repair man. when he opens the unit and turn it on hopefully  the defective part still smokes  and he can easily determine the problem. but  if you continue to press power button the part eventually would stop smoking and if there is no   easily noticeable burn mark  troubleshooting is more  difficult .