Tektronix 7633 and repair

[whitelabrat]

I've gotten my hands on a sweet Tek 7633 which should be good for at least 200Mhz with the right probe. A FET probe allows it to go into the Gig bands. Not bad for a mid-70's scope huh?

I liked this for it's Lincoln Log internals, but it also has a lot of Tek custom IC's.

Thing is that the 1khz square wave from the 4v calibration point is looking not so square.

Good scope?
Where do I begin to troubleshoot this? Do I dare ask how much it would be to bring this to a shop for repair?

[funkytek]

The 7633 mainframe is only rated at 100MHz. Although it will accept the faster 7000 series plugin's, the mainframe itself is limited to 100MHz.

That said, it is a good storage scope and they can be handy to have around and it probably does not need repair. It is probably your probe compensation. Does the waveform look rounded off?

The cal point is used to compensate the probe.
The Tek probe (and others) will have a small adjustment screw, to change the capacitive compensation between the individual probe and the particular vertical amp plugin you are using. Adjust this screw until the waveform looks square.

[gain-wire]

hi there
I was browsing the active threads and decided to read your because it talks about those wonderful Tek scopes(I own a 543A and a 564). What are "Lincoln log internals"

I am guessing they were some kind of special custom Integrated circuits or maybe tuned filters or delay lines?

cheers