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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

I've gotten it occasionally. I usually go there from what Firefox calls a private browsing window. Cookies aren't saved there and the first time going after restarting the browser is when I would get it, if I get it. Like I said, it's occasional.

Vince - K8ZW.

--
K8ZW

Weird. I NEVER have a Captcha / Not A Robot screen or button when using PayPal....

I do not save my password. Have to enter it every time, my choice. Works for me.

I do not understand the "how far along in the buying process you are" comment. All the screens on PayPal seem logical to me. And there are not many when sending money, either on their website only or through a vendor link to send funds.

So far it works well for me! Both as buyer and sending money to friends. Even for Tek supplies, to keep it on subject.?

Frank DuVal

Hello to all,

I should have many 3A1/3A6 and other 56x series plugins in my stock.? The problem is they are on the other side of Ohio at my other house.
Let me know what you want and I can look for them in a few weeks. Figure $20-$40 range plus shipping for most.? They will be complete (and most were tested/working years ago), but as-is now.

I also have many letter and 1xx series plugins.

You can email me direct at: jreese7010@...

or phone: 740-947-7103

Regards,

Jim

Jim Reese
Waverly, OH

Thanks for the guidance,

I suppose I have to take the cleaning challenge first as there are couple of suggestions for it.
As I didn't get any signal to R130...

I am also getting another unit to facilitate part swapping.

Regards,

Jouko

Bob,

Where are you located? there is a small handheld Tektronix scope in a
surpus store near me and that I can probably get cheaply. As best as I can
remember it is a 2xx model but I don't remember the complete model number.

On Wed, Nov 25, 2020 at 10:09 PM greenboxmaven via groups.io <ka2ivy=
[email protected]> wrote:

My main pleasure with equipment is finding inoperative or basket cases
and restoring them. I just finished a 2230 and an R-631B. This is an
account of the projects, skip now if you aren't interested.

The R361B was obtained from a member of this group, and I was quite
pleased with it when it arrived. I replaced the power cord, and tried it
out. It came alive, had a trace, then a loud snap was heard and it went
dead. I feared the worst, but continued with the work. It needed a bath,
and got it, followed by about ten hours in a hot box to dry it out. I
wanted to see if I could get the power supply working before I put the
jug back in after the cleanup. First tests were aweful. None of the
voltages were correct. The negative 100 volt supply is the reference for
everything else, and it was producing about 115 volts. All of the others
were very low. After a few hours of round and round circuit tracing, I
found the key problem- a partially shorted ceramic condenser. It was one
of the square red Erie brand ones, rated at 200 volts. There were two on
the board, I replaced them with 600 volt ceramic discs. There were two
other old electrolytics, I changed them out as well. The fuse protecting
the high voltage supply was gently blown, not fried and flashed all over
the glass tube. After finding and replacing two fried transistors in the
positive 125 volt supply, everything came alive and right on what they
should have been. I put a fuse in the high voltage supply, it came alive
with an output nearly 4KV, it should have been 3300. I turned the HV
adjustment all the way down, but could not get it below 3500. Both of
the transistors in the HV regulator are "special selected", and tested
good. After studying the manual, and not having exact original
transistors, I added a 12 meg resistor in parallel with the 2.2 meg
resisator coming from the moving contavt on the HV adjust pot. That
allowed me to adjust down to 3300 volts. I cleaned all the switches and
pots in both the mainframe and plug ins, re-installed the jug, and tried
it out. With adjustment of the sweep and position controls, I was
rewarded with a good bright trace. External signals and the built in
calibrator were displayed quite well. The vertical plug in I have is a
single trace differential, not especially useful to me, so I have a 72
dual trace on order. I will let the scope cook on the bench for another
day or so before I put it aside waiting for the dual trace preamp to
arrive. It will probably be used in my RTTY setup, the vertical response
is only about 600 KC.

The 2230 was a genuine basket case, almost entirely dismantled and
filthy with carbon dust. It was a freebee with another purchase at the
Rochester hamfest. I was quite skeptical until I got it home and found
that except for many screws, it was complete. It wasn't stored in the
dirt, it was operated in the filth because the knobs and front panel
were almost unreadable, and the focus pot was completely covered in
fuzz. Getting the front panel and control label plastic sheet off took a
bit of exploration, but WD-40 and a blow dryer softened up the adhesive
on the sheet, and it came off with very little damage. Now I could
remove the front panel to give it the cleaning it needed. Now fully
dismantled, everything got a bath. The cleaner and rinse water were
black as night, but everything cleaned up very well. After re-assembly,
cleaning and lubing switches and pots, it was time to see if it would
come alive. Turning the power on did nothing for a second or so, but the
pilot lamp blinked and the cooling fan moved. I remembered a similar
problem with broadcast waveform monitors and vector scopes, and replaced
all of the smaller low voltage electrolytic condensers in the circuit
that drives the inverter. Now, the same delay but the fan started and
the pilot lamp lit. There were some bright green blobs on the screen,
adjustement of the focus control produced brilliant menu text. After
exploring the controls, I found that one of them had to be pushed in to
display waveforms. I spent an hour or so exploring the locking action of
the pushbuttons, and there was no was to get two of the switches to
latch in, even if I borrowed the latch pins from other switches. The
others that were supposed to latch did. Because the buttons are plastic
stems on the switches, I filed a notch in the bottoms of the two that
would not latch. This allowed them to latch in, a gentle lift released
them. Everything seemed to work fine, the scope has many features I will
probably never use, but it displayed waveforms and would store them.
After several hours of cooking, I put the shield cover over the power
supply section and the brace that supports the top circuit board back
in. I turned it on, and was met with a total disaster. The only thing I
could get on the screen was blobs bouncing around. I shut it off
instantly, and started looking for bad solder joint on the bottom board
where the power supply is located. A solder splat was found and removed,
the scope came on and performed fine. After a few more hours of cooking,
I put the case and back panel on and ran it on test for a few more
hours. It performs very well, it will probably be used mostly in my
shack to troubleshoot RF circuits and monitor transmitter outputs
because it has a 100 MC. vertical bandwidth.

These are examples of the kind of projects I really like. Now, does
anyone have a 224 handheld scope project they would like to find a home
for? 73.

Bruce Gentry, KA2IVY

Hi Tom,

You must have done that calculation before the thread caught my
attention.

I've checked everything I wrote, and I don't see anywhere that I
have said, "but they might still have made a mistake" as you appear
to be attributing to me.

When did I write that, or are you simply making up quotes for effect?

Tektronix had excellent engineers. Way better than most, but in
terms of reliability, they very often compromised the quality of
their designs in production by using poorly specified parts, and
cheese ball fixes for their mistakes. Their "tented" parts are
legion, and some are very embarrassing to see as an engineer.
(See 2465 A1 board for plenty of examples...)

That said, it is a fool who changes the arrangement or parts
selection, of an RF circuit he does not understand.

-Chuck Harris

Tom Lee wrote:

Thanks

larry