This is a story posted at the year 2014 about Tektronix DMM4020 repair ( FLUKE 8808A ) in to avrfreaks forum.
The hero of this story, this is a person with much higher skills at troubleshooting that the average Joe.
The cause of the problem this is
extremely unusual.
I will not recommend this link below to be read by hobbyist capable only at replacing dead capacitors.
They will not be able to understand the fix, even if this it is offered, in the form of written thoughts.
https://www.avrfreaks.net/forum/tektronix-dmm-4020-repair