Recently found a Tektronix 2213 in nice condition. Was working fine, just during first operation after 30' released the magic smoke. The obvious Rifa Y2 mains suppression paper cap exploded & failed open.
Easy fix, took the opportunity and replaced every Rifa Y cap there (the mains exploded one & other four 2,2nF on the rectifier section) with fresh modern MKTs alongside with all the low voltage electrolytics with fresh Panasonics.
Left the big aluminum Sprague filter power HV cap intact as it looked well & from my little experience they rarely fail & on every replacement they measure fine for both capacitance & ESR.
All fine, oscillo runs smooth except one thing I noticed. During probe adjustment test I cannot get 50% duty cycle (top & bottoms are not equal). Note that this didn't happen before my slight repairs.
Is this normal?