My TDS784D does this as well. I recapped the CRT driver board, which
alleviated this for a spell. I was in email contact with another TDS owner
who found that in his case it was due to degradation of the connections to
the horizontal deflection coil. Apparently there's reasonable peak currents
there and the connector is not so hot.
Once I get through the pile of HP gear hogging my bench ATM, I'll give the
connections a look-see and a good clean, as this random, flickering
shearing is a little annoying.
On Thu, Jan 21, 2016 at 23:04 edbreya@... [TekScopes] <