Which oscilloscope would you tackle first?

[MaxwellFaraday]

About a year ago I "won" an auction that included a s-ton of lab equipment.  My ridiculously low bid $148 yielded an absurd amount of equipment in various states of operation.  I've enjoyed opening the cases of the simpler devices and exploring. 

Five oscilloscopes were included in the auction.  All power on, but have issues -- typically tube/display related.  I'd like to select one of these scopes and see if I can develop a deeper understanding of its design and operation.  I have no ambition to get any of these scopes operational, but that'd be nice.  More of an autopsy than a resuscitation.  I typically have lots of projects like this going at once as I find inspiration and ah-hah moments at odd times. 

I'd love to identify the best scope to start exploring.  A simple scope with a thoughtful design and some documentation seems obvious.  Can anyone offer a suggestion?  The 7104 and 7834 seem to be too complicated, although I love opening the cases of those and looking at the circuit poetry.

Here is what I have:

• Tek 475A (with DM44)
• Tek 2445B
• Tek 7104
• Tek 7834
• Hameg HM208

Thanks.

--k

[Ian.M]

IMHO, the Tek 2445B is probably the best candidate.  The Tek 475A has the added complexity of the built-in DMM, and the Hameg HM208 is a hybrid analog/digital scope.  OTOH Dave did a video (EEVblog #502) on the rather similar HM205.

Do try to get the 2445 fully operational - its a very well specified traditional CRO that would be an asset in any workshop that doesn't have a tens of Kilodollars test equipment budget. 

YMMV.

[The Guy]

Don´t stress.... I´ll take them all

[David Hess]

The 475A is the easiest to maintain of those so I would start there.  Except for the delta delayed sweep function, the DM44 is mostly separate from the oscilloscope itself.

[texaspyro]

I'd say 90% of Tek scope problems are due to bad power supply/distribution capacitors... particularly shorted dipped tantalum capacitors.  Next would be out-of-spec electrolytics in the power supply.

Shorted tantulum caps are usually easy to spot since they are usually burned to a charred crisp and stink to high heaven... the newer the failure, the greater the stink.

[MaxwellFaraday]

If you are in the SF Bay Area and interested in working with me on any of these, I'd be happy to give you one. 

[MaxwellFaraday]

There is also a Tek 2465 in the pile, if that makes any difference.  --k