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On Thu, Nov 26, 2020 at 12:52:21PM -0800, Jeff Dutky wrote:

I should put the 468 on my wish list, and maybe the 454 as well, but that way lies madness.

-- Jeff Dutky

Well, if you want to enjoy the madness, I have a pair of 468s to get rid of. One was
working pretty much but is showing signs of bad filter caps and the other is a parts scope.

Shipping is the real killer, of course.

You may want to look for a 454A; it has a larger screen. I completely went through a 454
and use that one a lot. I have a 454A in the queue for one of these days; picked that one
up off of craigslist as nonworking for $35. If you look hard you can find those for $30-50.

Then of course you can move up to the 2400 series :-)

And the 7000 series

And you'll need a curve tracer by this point

And ...

Paul


--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix/Linux - We don't do windows

The copy of the manual I have is not helpful in regards to cabling, there are no illustrations showing where the various connectors are located. By careful checking of the layout for every board, I was eventually able to determine what goes where and all appeared OK. I did adjust the routing, particularly around the CFC board as a lot of cables cross over each other and I found at least 1 cable was fully snapped into place; that was obviously the problem as it's all working now and appears to be accurate based upon my signal source; I have a higher frequency generator which I'll also try as the one I'm currently using maxs out at 30MHz.
Now I can use it to repair my HP spectrum analyser!

Add a 475A @ 250MHz to the list :-)

Dave wrote:

Is the 465B and the 475A the same too? Is the difference bandwidth? Doesn't seem that it'd
be release date as the 465B seems more advanced than the 465. I seem to recall we preferred
the "B" and thought it was the newer more advanced model.

Yes, the A and B models were later revisions of the un-suffixed models, and were usually better in some ways.

The 475A, for example, has a bandwidth of 250 MHz, but I have been told that it has "worse pulse response" as a result of the higher bandwidth. It also lacks a 2 mV range on the vertical channels, which is certainly a regression.

I'm currently restoring a 475A that I bought as a parts scope for my father's 475. It was quite evidently sick, and since the essence of my hobby is to diagnose and fix sick devices, I decided to try putting it back in working order rather than part it out. I fixed the bad +110V rail almost by accident, and am now working on the beam intensity amplifier (which had several diodes and transistors completely blown). Sadly, it looks like that might be all that is electronically wrong with the 475, and my fun will be over in a couple of week when the replacement transistors arrive.

I'm also fixing up my father's 2213, which has something marginal in the channel 1 vertical system, I have some residual marginality with his 475 involving cross talk in the vertical system and some stiff/scratchy pots, and I have a 2215A that I fixed the horizontal position adjustment on, but requires some adjustment to the 2 mV range on channel 1. So there's other fun to be had, but nothing quite as exciting as the repair required by the 475A.

Learning engineering minutia AND history and product lines.

Engineering is just the minutia of history with extra math.

-- Jeff Dutky

Jeff-..according to some most of here are already mad....and it only gets worse. Do not ask me why or how I personally know......
搁别苍é别

Dave,

There are a wide range of scopes in the 400 series. The 465 and 475 share a common design and have many parts in common. The main difference between them is about 100 MHz in bandwidth :-P

Here is the TekWIki page on the 400-series scopes

Here is a quick summary of some of the models in the 400 series:

The 454 is a 150 MHz dual time base analog scope (fastest GP scope to NOT use proprietary hybrid ICs)
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 465M is basically the same scope as the 465, but in the cabinet of a 455 (commercial version of the AN/USM 425)
The 466 is a 100 MHz dual time base scope with analog storage feature, otherwise similar, if not identical to the 465
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 475 is a 200 MHz dual time base scope, basically a faster, but otherwise identical version of the 465
The 485 is a 350 MHz dual time base scope with ALT horizontal display mode and a different front panel arrangement

There are some model numbers below the 454 but they are all lower bandwidth and I don't bother to think about them.

I should put the 468 on my wish list, and maybe the 454 as well, but that way lies madness.

-- Jeff Dutky

Real stunners!!!

From Tim P (UK)
From what I can see through the layer of crud, the red badge near the
calibrator knob is the logo of Livingston Laboratories.
LL were a high-end Lab instrument hire company in the UK. They would have
had a lot of Tek, HP, Marconi, EMI etc. kit for hire.
I'm going back at least 50 years, rather like that 545 !
Tim


On Thu, 26 Nov 2020 at 19:54, Dave Peterson via groups.io <davidpinsf=
[email protected]> wrote:

I had no idea: I thought the 475 was the one with the vertical input to
the right of the screen. I had to go and check myself - have I been calling
my scopes 465 by mistake!? No, they really do look identical - the 465 and
475. What's the difference between 465 and 475? Is the 465B and the 475A
the same too? Is the difference bandwidth? Doesn't seem that it'd be
release date as the 465B seems more advanced than the 465. I seem to recall
we preferred the "B" and thought it was the newer more advanced model.
Learning engineering minutia AND history and product lines.Dave
On Thursday, November 26, 2020, 11:16:48 AM PST, Jeff Dutky <
jeff.dutky@...> wrote:

Here is a parts scope I got from eBay
/g/TekScopes/album?id=257163

Most of the knobs are smashed, it's been spattered in something gray that
won't come off with soap or IPA, but when I powered it up it appears to be
in almost perfect working condition (I say "almost" because I didn't really
try to test it in any complete way, just fed the cal signal into both
channels, twiddled what knobs could be twiddled, and tried the different
button positions. Everything I tried seemed to be working perfectly).

I'd like to turn this from a parts scope into a second bench scope, but
I'll need to completely replace the front panel and knobs, unless I can
find a way to clean them up. Whatever is spattered all over it won't wash
off with either detergent and water or IPA, and I haven't tried any
stronger solvents or vigorous brushing. Any advice on how to clean the
front panel and remaining knobs, techniques or safe solvents, would be
appreciated.

-- Jeff Dutky

The latest is that a kind soul on EEVblog has decided to send me two of those Attn. Cap blocks from his old collection of parts. I have to pay only the postage. Such nice guys are still around! Should have it late next week.

Meanwhile, I will poke around some more and see what else I can find before placing an order for a few caps I like to replace. Have a great Thanksgiving everyone!

I had no idea: I thought the 475 was the one with the vertical input to the right of the screen. I had to go and check myself - have I been calling my scopes 465 by mistake!? No, they really do look identical - the 465 and 475. What's the difference between 465 and 475? Is the 465B and the 475A the same too? Is the difference bandwidth? Doesn't seem that it'd be release date as the 465B seems more advanced than the 465. I seem to recall we preferred the "B" and thought it was the newer more advanced model.
Learning engineering minutia AND history and product lines.Dave

Have you tried the VCF organization (Vintage Computer Fair)? They have branches in the US - NE, SE, SW, West, and Midwest, also Europe. I have been to the Midwest one and prices were pretty reasonable - not $1200, more like $50 -$250 - for working items. I would contact them for your closest org., and ask the moderator whom among their membership might have what you are seeking. I saw a working PDP11, many Commodores, TRS-80’s, IBM’s, Altair’s, IMSAI’s, MAC’s, etc. Plus you will have access to people that can readily fix all of the above, and have all of the required accessories needed to make them work.
Don Bitters

Here we go…



Grü?e, Carsten

Dave,

I'd also be interested in people's practical experience using both the delayed timebase and the vernier control.

The oscilloscope operators instruction manuals for the 475 and 2213 (as well as The XYZs of Oscilloscopes) have some discussion of how to use the delayed timebase to perform different measurements, but I've had trouble wrapping my head around the discussions without concrete examples to try out myself. Here is the discussion on page 29 from The XYZs of Oscilloscopes (1981, for the 2213, which has neither a full dual timebase nor a vernier for the delay):

"Dual time base scopes offer you all the measurement capabilities of single time base instruments, plus:

? convenient comparisons of signals at two different sweep speeds
? jitter-free triggering of delayed sweeps
? and timing measurement accuracy of 1.5%

Most of this increase in measurement performance is available because you can separately control the two sweep speeds and use them in three horizontal operating modes. These modes — in a 2215 — are A sweep only, B sweep only, or A intensified by B as well as B delayed. The HORIZONTAL MODE switch controls the operating mode and two SEC/DIV switches — concentrically mounted on a 2215 — control the sweep speeds.

When you use the ALT (for alternate horizontal mode) position the HORIZONTAL MODE switch, the scope will display the A sweep intensified by the B sweep and the B sweep delayed. As you set faster sweeps with the B SEC/DIV switch, you'll see the intensified zone on the A trace get smaller and B sweep expanded by the new speed setting. As you move the B DELAY TIME POSITION dial and the change where the B sweep starts, you'll see the intensified zone move across the A trace and see the B waveform change."

My father replaced a 475 (which has a vernier) with a 2213 (which has merely has a blank knob) as his daily use scope in the early 80s, after having used the 475 for 6 or 7 years. He had the choice between the 2213 and the 2215 (which has a proper dual time base and a vernier to control the delay) so I can only conclude that he didn't feel that those features were useful in his work (he was a service technician working on laboratory mass analysis equipment — mass spectrometry, spectroscopy, chromatography — and the computers that were connected to that equipment).

-- Jeff Dutky

My awful tryping (sic) strikes again. I should have written "garden shed near the river Trent?
I don't really see it as very ornamental either, even if cleaned up, it really is a mess. I don't think I would take it away if the seller gave me the money he is asking for it.
Colin

There aren't many tropical jungles in Stoke-on-Trent, but maybe it was stored in a garden shed neat the river Trent? The price is well-above any sane person would pay, surely?
Colin.

Here is a parts scope I got from eBay /g/TekScopes/album?id=257163

Most of the knobs are smashed, it's been spattered in something gray that won't come off with soap or IPA, but when I powered it up it appears to be in almost perfect working condition (I say "almost" because I didn't really try to test it in any complete way, just fed the cal signal into both channels, twiddled what knobs could be twiddled, and tried the different button positions. Everything I tried seemed to be working perfectly).

I'd like to turn this from a parts scope into a second bench scope, but I'll need to completely replace the front panel and knobs, unless I can find a way to clean them up. Whatever is spattered all over it won't wash off with either detergent and water or IPA, and I haven't tried any stronger solvents or vigorous brushing. Any advice on how to clean the front panel and remaining knobs, techniques or safe solvents, would be appreciated.

-- Jeff Dutky

Awfully high price for an "ornament"; and you'd need quite a substantial Christmas tree to hang that from!
-Dave

Just saw this on ebay in the UK :

Looks like it's been stored in a tropical jungle for a few years!

Anyone got any worse examples?

I checked my working scope this morning. I wish we could do inline pictures. I reviewed my tear down pictures and found that I had a shot of the DTP knob before I took it off, and am 99% certain that it's in the full ccw position. The new (parts) one is SN 29XXXX, the "old" working one is 31XXXX. The 29XXXX is at 0.35, the 31XXXX is at 0.25. Interestingly the 29XXXX has the fine dial setscrew at the "1" position. The 31XXXX has the setscrew at the "3.5" position. That's funky, but not really relevant?

I also wonder about the history behind these "min" settings. There's got to be some engineering behind it.

I don't recall them being non-zero back in my Army days. My experience, in general, is that there's not a lot of use for the B-delayed trigger. Perhaps more so in broadcast TV? (As another aside: in my profile picture I'm using the B-delayed function to examine a GHz radar transmit pulse triggered from a 20kHz system clock. Funny the things you remember). In any case, I don't recall the zero or values on the knob were of any interest. It was just a device to move the B-delayed signal under examination. This could be entirely my experience and use case only. I would be interested in learning what use cases in which values from this pot are needed.

Is this style of multi-turn pot just a means of obtaining fine delay control over a very large range? The ability to have nano-second resolution over a micro-second (or mili-second?) range. 1000-1 is a pretty large range.

Also interestingly, the other scope visible in my profile pic is a Tek 491 spectrum analyzer. I recall that it had a crank-knob on it. I was reviewing replacement knobs on the sphere site and came across that knob and all these memories came flooding back. I remember cranking on that thing to slew the spectrum analyzer across several orders of magnitude of frequency. So I wonder if these are just devices for handling fine control over a large range.

Dave

Colin,

Oh, I had expected some kind of calibration process, but it's just a bunch of constant offsets for different models.

I see that I am lucky to only be concerned with a model that is always set to 0.0 (the 475 and 475A). Good to know, however, since I would surely have been led astray on my 2215.

Thanks

-- Jeff Dutky