Hello All,
I am a relative newbie to repairing test equipment. I secured a clean Tek 475 last year from a garage sale to help me learn to align am and fm radios. Is is a beautiful scope and after just a little cleaning, it worked perfectly.
I recently fired it back up agin to work on another radio. I let it warm up for a good hour and when I returned it was dead. No power, no lights, no trace...nothing. Turns out the 50v low voltage power supply had a dead short. With the help of you guys on this forum, I tracked it down to a shorted tantalum capacitor. Replaced it with ease and fired it back up.
Now it powers up, I have a trace but something is off. The trace is distorted and the focus control is acting up. It used to defocus on either side of the centerline of the control but now at will only come close to focusing by turning the control all the way in one direction. The trace too is distorted. I am getting a vertical signal the changes deflection with controls but it is very noisy on distorted.
All the LV power supply voltages are within range with the exception of the 15v. It is measuring 18.9v.
I read on another post that the resistors around the focus control can be suspect. I am at a loss as to where to begin looking. Can someone point me in the right direction?