Re: worst condition Tektronix scope?


Since you're giving a summary, I'd like to add some comments (my response embedded):

On Thu, Nov 26, 2020 at 09:52 PM, Jeff Dutky wrote:

Here is a quick summary of some of the models in the 400 series:
1. The older 45x family, consisting of the 453, 453A, 454 and 454A. Very solid and heavy construction.
2. The newer family, with very different construction, consisting of the 464, 465, 465B, 466, 468, 475 and 475A. These share the same frame (with size adaptions) and construction and almost the same main board.
3. The 455 and 465M are from the same generation, with very similar front layout. Their internal construction is different from the 464 - 475A group.
4. The 485, with its 350 MHz BW @ 50 Ohm / 250 MHz BW @ 1 MOhm, although from the same period as the series 2. has a very different internal and front panel layout. I consider it one of the best and most beautiful 'scopes from the period, although not the easiest to service. It is absolutely packed with dipped tantalum caps...

The 454 is a 150 MHz dual time base analog scope (fastest GP scope to NOT use
proprietary hybrid ICs)
AFAIK, the 454 was the first portable 'scope to employ Tek's revolutionary bridged t-coil circuit. It also used distributed vertical plates. Its slower brother was the 453 (50 MHz).

The 455 is a 50 MHz dual time base scope with a non-rectangular front profile
The 465 is a 100 MHz dual time base scope
The 465B is an upgraded 465, with fewer components, easier to assemble and adjust, and containing several Tek proprietary IC's.

The 465M is basically the same scope as the 465, but in the cabinet of a 455
(commercial version of the AN/USM 425)
The 455 is built like a 455, not just a 465 in a 455 *cabinet*, e.g. it has the plug-in vertical input and time base module construction of the 455.

The 466 is a 100 MHz dual time base scope with analog storage feature,
otherwise similar, if not identical to the 465.
At the time, the 466 was one of the fastest-storing GP portable analog storage 'scopes on the market, certainly in the 100 MHz BW range. It had a reduced scan mode, with a different CRT with smaller graticule divisions in the center of the screen and control electronics modified to achieve the faster storage.

The 464 is like the 466 but has much slower storage. It lacks the reduced scan mode.
The 466 is a 465 with analog storage, it's more than just similar: The storage board is mounted in front of a 465 main board.

The 468 is a 100 MHz analog scope with a 10 MHz digitizing feature, DMM, and
an ALT rather than MIX horizontal display mode
The 468 is built on the 465B base.

The 475 is a 200 MHz dual time base scope, basically a faster, but otherwise

identical version of the 465.
The 475A is a "tuned" version of the 475. It lacks the 2 mV/div max. vert. sensitivity of the 475.

The 485 is a 350 MHz dual time base scope with ALT horizontal display mode and
a different front panel arrangement.
The 485 has a completely different internal construction than the 465/475

There are some model numbers below the 454,
like the 453 (50 MHz) but they are all lower bandwidth and the 422 (15 MHz)

and I don't bother to think about them.

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