Re: Tektronix 015-0580-00 Pocket Signal Generator
If you look at it shows use of the pocket signal generator with the DSA602. It is a single frequency, single level output. I have one but it didn't work properly with my DSA602 scope.I believe it is kaput and I haven't tried to repair it.
Leonard
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Re: 2247A PSU Troubleshooting
Raymond, Per your advice (and that clearly marked on the PCB!), I have purchased an isolation transformer. After watching a few videos online, I am still unsure whether I should connect ground from the Tek to the transformer. One video showed use of a 3-prong to 2-prong adapter where the ground wire is left unattached. Is this what you describe as ¡°floating the 2247A¡±? Thanks for your help! Nick On Sun, Mar 3, 2019 at 8:48 PM Nicholas Keller via Groups.Io <Nirokeforums= [email protected]> wrote: No, I was not using an isolation transformer (I don¡¯t have one) and yes I
was measuring between cap and chassis. I will look into getting a
transformer before testing across c2202 or doing other troubleshooting.
Thanks for the warning
Nick
On Sun, Mar 3, 2019 at 6:49 PM Raymond Domp Frank <hewpatek@...>
wrote:
On Mon, Mar 4, 2019 at 12:17 AM, Nicholas Keller wrote:
I measured 120-122VAC up to the diode ring. Does this
suggest that C2202 is bad?
I guess you realise you're measuring in an area that is directly connected
to the mains, no isolation? Take great care! *Do* use an isolation
transformer and *float your 2247A*.
Did you measure the 77 V across C2202 or between C2202 and chassis? The
latter would be incorrect, because the chassis is floating (with exception
of some C's) against C2202 (since that has a galvanic coupling to the
mains).
Raymond
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Re: 2246 no display/odd behavior
PSU is most likely culprit, you will have fun digging down to get to it. Search the archives for info on this, there were many threads regarding the way to test the PSU out of the scope (carefully) and likely suspects for replacement. Personally I had no problem with the 3 legged caps in the PSU (You will see which when you get in there) however others on this board disagreed. There is also a battery on the digital board which leaks (depends on version) that can cause problems. Its been a while since I repaired any of these so working from (poor) memory here.
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Re: 577 Curve tracer ringing CRT and noisy step generator
U360 is a plain vanilla 741 opamp
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Re: Tek Blue Paint - the story goes on ... :-)
Dave,
I recently stripped mine with acetone. That and gloves, a mask, and loads of paper towels had it stripped and sorted in a reasonable time. Work outdoors for best safety.
My mistake was using an abrasive attack at the start. Don't do that.
After a couple of coats of 'Etch Primer' the paint went on a treat. Sadly not the exact Tek blue but close enough to make me happy. Getting the right paint here to Australia (or the UK) is just too expensive.
Cheers, Brian.
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Re: 2246 no display/odd behavior
Do you have the service manual? You can find it at w140.com/tekwiki. Your measurements of ripple are only slightly greater than the specifications in table 6-4 which also lists the limits on the DC values of the supplies. The service manual also explains the function of the front panel buttons in the case of a diagnostic error at start up.
Roger
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Ed and Chuck:
I cranked up 7104/7A29/7B15. These were originally made for AES nuclear testing and 1000s used at LLNL, Los Alamos, LBL, etc.
It was CALed by a silent key, Walter, a super TEK/HP/Ham/Broadcast Engineer.
Setup squarewave test, transitions on graticule grid.
Perfect, NO observable distortion over the entire CRT faceplate! !
As the 7104 is 1 GHz BW and a huge bench scope, the CRTs must be completely different designs, although both use the MCP.
Perhaps the CRT of 2467B was a compromise?
bonne journ¨¦e
Jon
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Hi Ed,
Vertical deflections that remain flat for the entire
width of the screen, regardless of the sweep speed, are
by my definition low frequencies.
Sweep speed has no effect on my scope's distortions.
Nor does the relative position of the horizontal or vertical
position controls. The warp is always the same at the
same point on the screen.
If it were a power supply coupling problem, the distortion
should move with the horizontal and vertical position
controls, not remain stapled to a physical location on
the screen.
This really has to be a static problem with the CRT. I am
hopeful that it can be minimized through some careful jiggering
of bias adjustments to the static properties of the CRT,
but long ago I lost hope for that.
It meets tektronix's specs, but no customer would have put
up with such a warped base-line trace in the middle of the screen.
When I noticed Jean-Paul's posting describing his geometry
problem, and then Siggi weighed in with a similar issue, I began
to have a little hope that it might be a common issue with
the scope.... But, I now think the commonality is simply a
common response to being thrown into a scrap bin.
-Chuck Harris
Ed Breya via Groups.Io wrote:
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Chuck said:
"Power supply coupling between the amplifiers would most
certainly have a dynamic component to it. This is purely
static in nature. I can move the dot using the H and V
position controls, and retrace any line on the screen."
Yes, but it appears all the measurements done have been at DC and low frequencies. The deflection amplifiers and power supplies have finite rejection in terms of CMRR and PSRR, at DC as well as a function of frequency. What if the amplifiers change slightly (linearity), or the CM voltage affects them or the deflection plate bias at the extremes (corners) of the display?
Power supply and CM and differential gain measurements could be done at DC, with high a resolution DVM.
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I am certain that they are NOT all like this.... At least
not to the same degree mine is.
For instance, mine cannot, ever, under any circumstances
develop a straight trace at the center of the screen. It
always bows upwards.
The center should be the one place that is golden for any
CRT, as it is the sweet spot for the vertical deflection
plates, geometry, and the box lens.
The center should not be affected by the geometry control;
only the outer 1/4 of the screen. And, on further more
careful observation, the center wiggle on my CRT is not
affected by the geometry control... only the outer edges.
Most folks run into some trouble with the geometry setting
because they can't see, division-by-division what the
geometry setting is doing to the screen's distortion.
Displaying a grid, with 1 division/square, shows this up
very easily... allowing you to simply turn the geometry
from one side to the other, observing the effect, and
deciding what is least annoying to you.
Similarly, the Edge Focus, only affects the outer 1/8
of the screen.
I think it is probable that my scope has been the subject
of a series of Dr. Frankenstein experiments by its previous
owner. The scope was probably subject to a major hit, and
all of the broken bits of the case or front panel were
replaced.
There is probably a good reason why it was relegated to
the scrap bin.
-Chuck Harris
John Ferguson via Groups.Io wrote:
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Chuck,
I'm a little surprised that someone hasn't surfaced to tell us that they were all
like that. Surely one of the thousands of participants on this wonderful site must
know, or have been there when these scopes were designed.
perplexing.
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Re: Looking for Sony-Tektronix 318 Logic Analyser Operator's Guide
On Tue, Mar 12, 2019 at 11:28 AM, Roy Thistle wrote:
Army one has a reasonable operator's section (Chapter 4?).
It is chapter/part 3 in the Army one.
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Re: Tek Blue Paint at Stuff Day
Agreed...perhaps a shipping container......what really grieves me is before moving out there I spent 4 years commuting back and forth from the UK to Everett every 4 weeks or so and my route was to fly? Air Canada to Vancouver and drive down Route 99/I5 so was passing within a couple of hours drive of this gold mine and didn't know it existed! With all the air miles I ended up as a Star Alliance Gold-pressed Latinum member (or something) and with that baggage allowance I could just about fill the aircraft hold for free each trip!
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On 3/13/2019 12:22 AM, David Slipper wrote: What a shame there is no "Stuff Day" in the UK :-(
On 13/03/2019 00:06, walter shawlee wrote:
Just a note that I will have a few new cans of Tek blue spray paint (the exact stuff)
at our upcoming Stuff Day event at Sphere (april 13th). Maybe somebody can drive a few cans back for others? it can't be shipped by air, so only ground transport is possible. what anightmare it was to buy orignally.
Lots of great Tek 300 series portables will also be at Stuff Day, and you can browse the Tek and hp knob drawers for that weird knob you really need. way too many to photograph and list on line, and of course, the knobs have no numbers on them... there's also tons of original printed manuals by the pound.
stuff day:
all the best,
walter walter2 -at- sphere.bc.ca
sphere research corp.
.
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I have a chance to buy a 465B which seems to work fine Both time bases show good traces etc The
owner is asking 100.00 I was going to ask a stupid question: is the USD, UKP or EUR. But they are all about the same thing now! Craig
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Re: Tek Blue Paint - the story goes on ... :-)
Very nice work John- would that paint stripper remove my drool after looking at your collection? Seriously, a wonderful collection you¡¯ve amassed- thanks for the post!
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On Mar 12, 2019, at 5:44 PM, John Williams <books4you@...> wrote:
Dave I have stripped a lot of Tektronix scopes. First, never use oven cleaner. I have used it on motorcycle parts and it is highly corrosive to aluminum. Second, aircraft stripper is not necessary either. I always have used the lightweight paint stripper from the hardware store which has worked just fine. If you want to see pictures of just some of my repaints take a look at my google photos.
John.
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Re: 465B Square Wave problem
I had to put this aside due to other things but during that time I kept working on other electronics and have really learned a lot. I had been over that scope with a fine tooth comb, I checked every component. I needed a break. This scope like most 465s have been sitting. I had tried cleaning the contacts with automotive MAF cleaner previous to all this, all I had on hand that seemed reasonable. The problem was corrosion in the switches. I finally broke down and bought a can of DeoxIT D5. This fixed the traces corners. I didnt even need a calibrator to adjust them after that. Although I now own a working cal pak. WooHoo!
I have this theme going where when sometimes I fix something, something else breaks. My Beam Finder switch was damaged so I replaced it with a donor. Now my traces are flickering intensity badly. not sure if its related. Off to troubleshoot...
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Chuck said:
"Power supply coupling between the amplifiers would most
certainly have a dynamic component to it. This is purely
static in nature. I can move the dot using the H and V
position controls, and retrace any line on the screen."
Yes, but it appears all the measurements done have been at DC and low frequencies. The deflection amplifiers and power supplies have finite rejection in terms of CMRR and PSRR, at DC as well as a function of frequency. What if the amplifiers change slightly (linearity), or the CM voltage affects them or the deflection plate bias at the extremes (corners) of the display?
Power supply and CM and differential gain measurements could be done at DC, with high a resolution DVM.
One thing that may help is to run the display in a raster mode at fairly high frequency. In my 7K tester plug-in, I run a 10 or 20 MHz oscillator and deflect the vertical to just over the screen limits, and in un-triggered, and/or the right sweep settings, get a full-screen raster of the X and Y range, for viewing the overall brightness capability and uniformity, pincushion, and bad phosphor spots. This can show the box outline at the extremes, but nothing about the center response - but it is at high rep rate. The same can be easily done by putting in a high frequency sine or triangle and setting up the sweep to fill the screen. This sort of test may not be appropriate for MCP displays though, since it needs a lot of beam current to fill the entire screen area at high brightness.
Regarding the 2467 vs 7104, I see now that they are quite different - I thought they used the same CRT. If the 2467 one is much more compact, I can picture that a lot of tradeoffs were made.
Ed
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Re: 222/224 Portable scope CRT pinout?
Ah yeah, the trick is that I am unsure of the actual pin numbering on the CRT itself.
Is that shown in the manual you have?
Thanks!
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Re: 222/224 Portable scope CRT pinout?
Jared,
According to the service manual (with schematics), 070-8405-01, from Qservice, the CRT pinout is:
1 Control grid
2 Filament
3 Cathode and Filament
4 Focus
5 Astig
6 Vert-
7 Vert+
8 Horiz+
9 Horiz-
--John Gord
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On Tue, Mar 12, 2019 at 09:02 PM, Jared Cabot wrote:
I'm currently repairing a 224 portable scope (the battery powered hand held
one) and had a small problem where the plug for the CRT came apart when I was
unplugging it...
I think I got the pinout in the correct order, but the service manual doesn't
seem to show the pin numbering of the CRT (or I'm blind....)
Can anyone open up their unit and take a few photos of the CRT plug area so I
can compare to double check I got it correct?
Thanks!
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This scope looks like it has two timebases. However it actually has three. The fastest sweep speeds use the third time base. So one should probably test ALL sweep speeds to make sure they all work. I have been fooled on this more than once.
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222/224 Portable scope CRT pinout?
I'm currently repairing a 224 portable scope (the battery powered hand held one) and had a small problem where the plug for the CRT came apart when I was unplugging it...
I think I got the pinout in the correct order, but the service manual doesn't seem to show the pin numbering of the CRT (or I'm blind....)
Can anyone open up their unit and take a few photos of the CRT plug area so I can compare to double check I got it correct?
Thanks!
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Chuck,
I'm a little surprised that someone hasn't surfaced to tell us that they were all like that.? Surely one of the thousands of participants on this wonderful site must know, or have been there when these scopes were designed.
perplexing.
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Brian Cockburn
Jean-Paul
Timothy
Jared Cabot
John Williams