Rebonjour a tous:
Same low SN B062 2465B
has extrême CH1,2 compression on lower part of display.
CH 3, 4 are perfect and normal.
Photo Album: 2465B CH1,2 compression
Taken with 100 kHz triangle on CH 1 and CH2,
position upper nearly linear position lower screen, extreme compression and non linearity.
Transient response is also severely affected as position of traces is moved.
1/ all PSU voltages normal,
2/ using substitute A5 so no CAL data is valid.
3/ Is there an adjustment or bias eg on U400 channel sw ?
4/ Pulled U400, cleaned the hybrid contacts, no change
is there a place to test signals into U400 from CH 1,2 preamp U100, U200?
Assume U400 155-0236-00 is bad and replace (VERY costly!)