[R-390] OT: Tubes needed for TEK561A

[Scott, Barry (Clyde B)]

I dragged the scope out for something this past weekend and the vertical amp
has developed problems.  I checked the tubes and both 6DJ8s (EC88?) are very
weak.  Just my luck -- these are apparently popular with the audiophile gang
and, thus, they can be pretty expensive.  Anyone have any good suggestions
on an inexpensive source for these?

Hopefully the problem is with these tubes.  I have zero experience
troubleshooting scopes.  Fortunately, the module is not complex so it might
be a simple case of finding a bad component and replacing it (of course
using the appropriate silver solder (which I will also need...sigh)).

Thanks,

Barry(III) - N4BUQ