You can get an ESR meter for $50 from everybody's favorite made-in-China electronics supplier, matelectronics.com.
http://matelectronics.com/test-equip...-mul-3333.html
Or if you have a scope and signal generator, you can use them as an ESR meter. Instructions here:
http://fullnet.com/~tomg/esrscope.htm
As far as the black bands go, my guess would be that you bumped something around the horizontal module when you were troubleshooting the amplifier, but if you reseated the module and that did not fix anything, that's not the case. Maybe there's a width or horizontal hold control somewhere that is dirty and got disturbed?
Anyway, keep at it and troubleshoot one thing at a time. I am almost completely certain you are dealing with multiple failures that each need to be corrected, not a single failure that is causing all the faults you are observing.