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Question for the OP.......does your scope have either of the side options? RS232, GPIB? If so disconnect them. The battery backup is on the side option on these so if there is no option installed the scope shouldn't really be booting into any weird state.


---In TekScopes@..., <edbreya@...> wrote :

I looked at the 2230 service manual. In section 5 it describes adjusting the store/nonstore registration using a box generator accessible from the diagnostics menu.

So the X isn't normally seen or user accessible. I think it was probably a factory setup mode for coarse checking and alignment during production, to make sure the digital display basically worked and was on-screen - if it was too far out of whack, you may not be able to read the menus. Also, in production, you wouldn't want to be fooling around waiting for boot-up and navigating menus while firing up a unit. A hardware override can force the mode, and it's ready to go, and you can see the status. I don't recall how much automation was applied, but they likely checked the fine details via GPIB once the units were proofed and operational past a certain point.

If you look at the screen shot, you can imagine that if the X was tweaked slightly up and left, the center would be on the CRT origin, and the lines would intersect the graticule grids almost perfectly, which would be correct.

I'm still guessing a jumper or DIP switch setting activates it, but there likely won't be anything said about it in the manual.

I've only played around with it briefly, but I'm pretty sure both cursors move smoothly. Everything seems to be pointing to U400 but have not checked voltages yet.

Previous owner had taken it to a cal lab and the paperwork came back from there stating U400 is bad. I don't know if a cal lab would have checked voltages, though. Will know more soon.

Thanks,
Barry - N4BUQ

I looked at the 2230 service manual. In section 5 it describes adjusting the store/nonstore registration using a box generator accessible from the diagnostics menu.

So the X isn't normally seen or user accessible. I think it was probably a factory setup mode for coarse checking and alignment during production, to make sure the digital display basically worked and was on-screen - if it was too far out of whack, you may not be able to read the menus. Also, in production, you wouldn't want to be fooling around waiting for boot-up and navigating menus while firing up a unit. A hardware override can force the mode, and it's ready to go, and you can see the status. I don't recall how much automation was applied, but they likely checked the fine details via GPIB once the units were proofed and operational past a certain point.

If you look at the screen shot, you can imagine that if the X was tweaked slightly up and left, the center would be on the CRT origin, and the lines would intersect the graticule grids almost perfectly, which would be correct.

I'm still guessing a jumper or DIP switch setting activates it, but there likely won't be anything said about it in the manual.

You are right, it could be U400.? But I would try the other things first, lol.? In Barry's case, he has a source for an alternate U400.? I would try that AFTER?verifying all voltages are in spec.? No need to damage the alternative U400 with bad supply voltages.?
I am waiting to hear that your "new" U400 corrects your problem.

From: "very_fuzzy_logic@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Wednesday, March 30, 2016 3:21 PM
Subject: Re: [TekScopes] Re: 2465B U400 Availability?

? Two points:

Barry's 2465B and mine have very similar issues with non-linearity on ch1 and ch2 but ch3 and ch4 OK. At least on my scope the power rails are ok for voltage and ripple. I also checked the power supplies where they have common decoupling to U100 and U200 and so far have not found anything amiss. There are threads here and elsewhere suggesting U400 as a possible cause and it's price is consistent with it failing frequently! I haven't yet checked U400 bias current or the voltages on the channel select inputs.

Secondly, Barry has several noisy analogue controls, DAC stability could be a common cause. Do the y and t cursors move smoothly? If they don't then it would be well worth checking the DAC output, there is setup procedure near the beginning of the calibration section of the manual that puts the DAC output on one of the DIP header pins and it responds to cursor movement - should be a good test.

Meanwhile my replacement U400 has been stuck in transit for over a week en route to the UK!

Roger #yiv2028227971 #yiv2028227971 -- #yiv2028227971ygrp-mkp {border:1px solid #d8d8d8;font-family:Arial;margin:10px 0;padding:0 10px;}#yiv2028227971 #yiv2028227971ygrp-mkp hr {border:1px solid #d8d8d8;}#yiv2028227971 #yiv2028227971ygrp-mkp #yiv2028227971hd {color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px 0;}#yiv2028227971 #yiv2028227971ygrp-mkp #yiv2028227971ads {margin-bottom:10px;}#yiv2028227971 #yiv2028227971ygrp-mkp .yiv2028227971ad {padding:0 0;}#yiv2028227971 #yiv2028227971ygrp-mkp .yiv2028227971ad p {margin:0;}#yiv2028227971 #yiv2028227971ygrp-mkp .yiv2028227971ad a {color:#0000ff;text-decoration:none;}#yiv2028227971 #yiv2028227971ygrp-sponsor #yiv2028227971ygrp-lc {font-family:Arial;}#yiv2028227971 #yiv2028227971ygrp-sponsor #yiv2028227971ygrp-lc #yiv2028227971hd {margin:10px 0px;font-weight:700;font-size:78%;line-height:122%;}#yiv2028227971 #yiv2028227971ygrp-sponsor #yiv2028227971ygrp-lc .yiv2028227971ad {margin-bottom:10px;padding:0 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Two points:

Barry's 2465B and mine have very similar issues with non-linearity on ch1 and ch2 but ch3 and ch4 OK. At least on my scope the power rails are ok for voltage and ripple. I also checked the power supplies where they have common decoupling to U100 and U200 and so far have not found anything amiss. There are threads here and elsewhere suggesting U400 as a possible cause and it's price is consistent with it failing frequently! I haven't yet checked U400 bias current or the voltages on the channel select inputs.

Secondly, Barry has several noisy analogue controls, DAC stability could be a common cause. Do the y and t cursors move smoothly? If they don't then it would be well worth checking the DAC output, there is setup procedure near the beginning of the calibration section of the manual that puts the DAC output on one of the DIP header pins and it responds to cursor movement - should be a good test.

Meanwhile my replacement U400 has been stuck in transit for over a week en route to the UK!

Roger

Only Channels 1 and 2 exhibit vertical linearity issues.

I made this comment earlier today but somehow it didn't get through, it seems:

With these symptoms, I have *only* seen U400 as the culprit during the past 4 or five times this came up on this forum.

Raymond

Only Channels 1 and 2 exhibit vertical linearity issues.? This is re-assuring for the CRT.? Since its only Channels 1 & 2 but its both channels in the same way, I suspect its a circuit problem and not likely the U400.? Keep in mind that bad supply rails can cause vertical distortion AND less sharp traces.? Its unusual for these scopes to have good supply rails after 20+ years.? Nearly all require re-capping the power supply and the A5 board as a minimum.
Overall, the frame seems twisted about 1/8" or more (doesn't sit flat on the bench). It's probably not too difficult to straighten this out.

This is the reason for my concern about being dropped.? This case is very sturdy, meant to be a portable scope.? I cant imagine how to distort the case with a normal blow.? I have an older rack mounted 2465 that was dropped hard, broke the CRT (at the neck, near the rear pins) and bent the screws holding it to the rack.? But the frame is still straight.

As for the broken fanI have never owned?a 2400 series scope that didn't come with some kind of fan issue.? Yours seems minor compared to others.?
BTW, as I mentioned, this appears to be a 1994 manufacture date and a 65k serial number. Was this pretty close to the end of production?I have not found documentation of serial numbers vs manufacture date.? But its clear that higher numbers means later manufacture dates.? Also, Bxxxxxx numbers were manufactured in Beaverton Oregon, while others were assembled elsewhere (eg UK).? There seemed to be many changes after serial numbers B050000, especially in the A5 board.??But I don't know if that is before 1990s or not.? I used 2465, 2465A, and 2465B from the early 80's until my retirement in 1999.? I never cared about manufacture dates, only calibration?status/date.? They are fine analog scopes.

From: "Barry n4buq@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Wednesday, March 30, 2016 8:11 AM
Subject: Re: [TekScopes] Re: 2465B U400 Availability?

? Only Channels 1 and 2 exhibit vertical linearity issues. Channels 3 and 4 appear to be okay. It won't be a big deal to swap U400 with my 2445 to see if it fixes the problem.

I do notice the trace is not as sharp as I'd like/expect (my 2445 shows a bit crisper and I think they use the same CRT), so not sure if there's internal damage or just needs adjusting.

There's a slight dent in the bottom rear of the cabinet and I think I can tell a small distortion in one of the frame pieces that meets up with the rear panel but the direction of that distortion seems odd (e.g. it would indicate an outward force rather than an inward force such as a strike to the rear panel, etc.). No telling just what/how it was hit. Overall, the frame seems twisted about 1/8" or more (doesn't sit flat on the bench). It's probably not too difficult to straighten this out.

As for the broken fan, the way the fan "shroud" is designed, it presses against the center of the fan motor and it wouldn't really take very much pressure (with the cabinet removed) to break the small plastic supports that center the motor in the frame. I plan to CA glue those back in and see how that holds up. If not, a replacement appears pretty easy to find. The fan is slightly noisier than the other style fan in my 2445. I wish it had the same style fan in this model.

BTW, as I mentioned, this appears to be a 1994 manufacture date and a 65k serial number. Was this pretty close to the end of production? I've looked for serial number correlation but not finding too much on that for this model. TekWiki just says "Produced from 1984 to ?".

Thanks,
Barry - N4BUQ

----- Original Message -----

From: "machine guy machineguy59@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Tuesday, March 29, 2016 11:00:38 PM
Subject: Re: [TekScopes] Re: 2465B U400 Availability?

Its troubling that the scope ma have been dropped so hard.? Double check the
CRT.? If all channels show similar distortion you may have a CRT fault.? Its
repairable though.

From: "Barry n4buq@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Tuesday, March 29, 2016 9:47 PM
Subject: Re: [TekScopes] Re: 2465B U400 Availability?

? Got a chance to open up the 2465B tonight. Pretty clean and no obvious
? signs of capacitor issues (leakage, etc.). It's a 65K serial number and
? appears to have been made in 1994.

Fan is broken. Two of the three spokes that hold the motor are broken and the
blades were stuck against the back of the main frame. I managed to push
those in place well enough to hold and the fan now runs; however, no telling
how long it ran without that so heat damage could be a factor. Not sure, but
the scope might have taken a small hit - enough to break that fan and cause
the entire frame to be twisted just a tad.

Reseated U400 just for fun but didn't cure the problem.

Need to check voltages and ripple and possibly reseat some connectors as the
controls and CRT seem to be intermittent with some apparent noise here and
there.

Also will want to try swapping U400 with my 2445 to see how much that cures.

Neat scope!

Thanks,
Barry - N4BUQ

----- Original Message -----

From: "Barry n4buq@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Tuesday, March 29, 2016 2:22:39 PM
Subject: [TekScopes] Re: 2465B U400 Availability?

I bought the 2465B today. Nice physical condition on the outside but
haven't
had time to open it yet.

Seems there's a bit of noise on some channels. I'm guessing power supply
issues.

Changing the vertical position of the trace definitely changes the height
of
the trace as I move from bottom to top. Looks like U400 is indeed
problematic.

Will know more once I dig into it.

Thanks,
Barry - N4BUQ

I'm looking at buying a 2465B that's supposedly needs a U400. Scope
appears
to work somewhat (calibrator trace looks good, etc.) and price is good.

I'm wondering what I may be getting into here. Are U400's very hard to
find
at a reasonable price? I see them on eBay but wondered if there's a
better
source (perhaps here?) for them.

Also, is it "normal" for the 2465B to display any trace (e.g. the
calibrator)
when U400 is bad? In other words, I'm wondering if U400 is really the
problem with it or possibly something else (apparently it won't
calibrate).
NVRAM maybe?

Thanks,
Barry - N4BUQ

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Oh well, so much for that. Another possibility is to duplicate 2230 ROMs and try in a 2220.

As I mentioned, the purpose of the big X could be to align the storage display with the CRT. The lines should cross at the center, and the slopes should be to confirm linearity and set them to cross the CRT graticule lines at the intersections all the way to the corners. These adjustments are in the vector generator, as I recall. There would be offset and gain adjustment for vertical and horizontal. Maybe it's a factory setting not normally accessible to the user.

If the X isn't for that, then there may be something in the diagnostic menu to draw some kind of pattern for this purpose. There should be something in the service manual about this alignment process.

Ed

The ROMS in the 2220 are 1603976-04 and 160-3975-04, different to the 2230 and a quick comparison between the boards doesn't appear to have much difference apart from the obvious lack of cursor control and missing switches.
I don't think the X is a cal feature, at least I've never seen it and don't see what use it would be. Very strange.


---In TekScopes@..., <edbreya@...> wrote :

I don't recall exactly how the 2220 was differentiated from the 2230 for product positioning, but I do know the guts are mostly the same. I think the 2220 was reduced in performance by limiting the BW to 60 MHz (with parts on the main board) vs 100 for the 2230, and maybe lower sample rate and record length. I think the brain identified the model by jumpers (0 ohm resistor jumpers) on the digital board, although they may instead have different ROMs. If anyone with these models can compare, it would be evident. I also thought the 2220 had on-screen readout, but fewer features within the operating menus.

If the ROMs are the same between models, this could be a case where a 2220 can be mostly converted to a 2230, except for any major items missing.

I saw the picture of the big X - it certainly is big, and appears to be generated by the digital display system, like a calibration signal to align the storage mode to the CRT face. Maybe there's a jumper or DIP switch set to the wrong position, or loose, forcing a cal mode. Another possibility is that it's a fault indicator showing X-out - that there's a major problem such as the brain being confused about what model it should be, so it just sits there. Perhaps there's an intermittent fault in the ID process, or maybe someone hacked it part way and got it all confused. Obviously, the brain must be working in order to present the X on screen.

I'd recommend studying the manuals and circuits and boards and ROMs and jumpers and DIP switches to see if anything looks different from normal. Especially check in the adjustments section, to see what's done for aligning the store/nonstore registration. I'd guess it's a jumper or DIP switch setting, rather than a diagnostic menu item, to make the X, and pots on the vector board to tweak it to the CRT.

Ed

2x7T11, 1x7S11/S-1 and a 7M11 all on the auction site right now, started at
99 cents. No affiliation, just know there are people looking for these!
Nathan KK4REY

Sent using CloudMagic Email
[]

Hello all, new to the group and happy to be here.

I just wrote a long intro about me and my new Tek 465 into the Yahoo groups
'new post' textbox, but it seems to have vanished ... so I'll briefly recap
(pardon the pun). I am a web and database programmer during the day but
have dabbled in electronics since I was 10. I'm in my 30s now and getting
back into modding my audio tube amps. I've always been building kits and
fixing through parts swapping in TV power supply boards, digital Arduino
projects, RC planes etc. But I've never really learned the math or
theory/design side of the analog world. As I'm looking to build some
personal audio gear (active crossovers, maybe some tube mono-blocks) I'm
teaching myself more theory. And I'm a very visual person and like learning
through gear so thought I'd get an analog o-scope.

Well I stumbed upon an as-is Tek 465 on Craiglist that I picked up Monday
near Chicago. I'm blown away by the detail in the service manual I found
online and the serviceability, and am starting with the power supply diag
in the manual to try to get things running. I don't have high expectations
for accuracy - I know a detailed calibration is a profession in itself. But
getting even rough readings would be a big help for me as I learn.

Current condition of the scope is a single dot in the center with no sweep.
Fan and lights work, knobs in good shape. Very complete scope but the sweep
IC gets super hot. I figured I'd have to swap a lot of caps and transistors
and maybe some regulators, but hoping I don't have to source the custom ICs
(but found a source so I guess there's hope).

So far I've confirmed a solid +55v rail, +15v rail and a drooping +5v and
no -8v with my DMM. The +5v droop goes away if I isolate the horizontal amp
board by pulling the connector. I posted on the EEVBlog forum and got a
response saying to check the ripple as well; seems I need another (working)
scope? Any hope that a cheap USB scope (opposite end of spectrum from this
beast!) would suffice?

Thanks in advance for your knowledge; I'll ask more detailed questions and
post pics as I get into things.

- Neil

I don't recall exactly how the 2220 was differentiated from the 2230 for product positioning, but I do know the guts are mostly the same. I think the 2220 was reduced in performance by limiting the BW to 60 MHz (with parts on the main board) vs 100 for the 2230, and maybe lower sample rate and record length. I think the brain identified the model by jumpers (0 ohm resistor jumpers) on the digital board, although they may instead have different ROMs. If anyone with these models can compare, it would be evident. I also thought the 2220 had on-screen readout, but fewer features within the operating menus.

If the ROMs are the same between models, this could be a case where a 2220 can be mostly converted to a 2230, except for any major items missing.

I saw the picture of the big X - it certainly is big, and appears to be generated by the digital display system, like a calibration signal to align the storage mode to the CRT face. Maybe there's a jumper or DIP switch set to the wrong position, or loose, forcing a cal mode. Another possibility is that it's a fault indicator showing X-out - that there's a major problem such as the brain being confused about what model it should be, so it just sits there. Perhaps there's an intermittent fault in the ID process, or maybe someone hacked it part way and got it all confused. Obviously, the brain must be working in order to present the X on screen.

I'd recommend studying the manuals and circuits and boards and ROMs and jumpers and DIP switches to see if anything looks different from normal. Especially check in the adjustments section, to see what's done for aligning the store/nonstore registration. I'd guess it's a jumper or DIP switch setting, rather than a diagnostic menu item, to make the X, and pots on the vector board to tweak it to the CRT.

Ed

Hi all, just introducing myself and my current project to the group. I am a web programmer during the day but have always been interested in electronics. Always have been a 'part swapper' level of a electronic repair tech but know a bit of theory and how to read schematics etc. Also am a fan of audio tube amplifiers and looking to build my own circuits for home audio projects (preamp, active crossovers). Also need to fix a TV power supply for my brother at the moment; and have a tape deck I need to diagnose deeper than I can do with a DMM. So now I'm wanting to learn more; taking a class and just now getting into scopes and the deeper math side of things. But sticking with low Mhz needs and analog for starters.


Picked up a Tek 465 off Craiglist on Monday - it has a single non-sweeping dot in the center and a toasty hot sweep IC. I've been following the service manual diag steps and seeing low voltage on the +5v rail until the horizontal amp board connector is removed, then it stabilizes to 5v per my DMM. No -8v to be seen but solid +55 and +15. I have been told on the EEBlog forum to check for ripple; seems I need to buy another (working) scope to get that confirmed which I think I'll do. Any chance the less expensive USB O-Scopes can do ripple?


I see the custom Tek Sweep IC can be had from some specialty web sites so I may order one of those based on mine running too hot to touch. Otherwise I'm planning to test and swap all caps and transistors as needed. I also have a quality Tek o-probe on the way and a good Weller soldering station and pretty well equipped bench.


Thanks in advance; I'm hoping to ask more detailed questions as I have them but am starting testing from the power supply end.


- Neil

Besides, the links don't work. In the "New file..." messages the folder name is either truncated (too long?), or changed afterwards in the Files section (is that possible?). Very strange, the text -fixed is removed from the folder name and replaced by a space.
Albert


---In TekScopes@..., <malcolm.r.hunter@...> wrote :

Hi Darren,

If you upload photos to the Photos section, people can view them in their
web browser rather than having to download them first.

Malcolm

Barry, it's what you suggest, it will be ripple after double rectification. But the repetition frequency is still 60 Hz; only in case of ideal symmetry the frequency appears as 120 Hz.
Hence set the trigger mode at LINE.
If you trigger on the signal then the trigger circuitry will normally recognize 120 positive (at + slope) level crossings per second. Depending on sweep speed and hold-off time you have two alternating waveforms superimposed, or "at random" one of these two (maybe stable, maybe now and then jumping to the other waveform).

Albert


---In TekScopes@..., <n4buq@...> wrote :

In the 2400 series manuals, the table that defines the measurements for voltage and ripple state (for ripple measurement):

p-p Ripple at Two
Times Line Frequency

How is this supposed to be done? With a 60Hz line frequency (U.S.), is this supposed to be performed with the scope measuring the ripple triggered at 120Hz or am I misinterpreting what's being stated? Is it simply assumed that any ripple will present itself at twice the line frequency (full-wave rectification) and the scope being used to measure this will simply trigger at that frequency (assumedly using a fairly slow sweep speed to better see the waveform)?

Thanks,
Barry - N4BUQ

They are referring to ripple produced by the 120 Hz variation from the
full wave rectifier at the input. Set the measuring oscilloscope to
line triggering; that is what it is there for.

Data on the 2220 and 2221 is pretty slim; I have never see schematics
or the service manual for them. Similarities with the 2230 which make
it the closest match and 2235 series in general include:

- Production dates coinciding with the 2230.
- 20pF input capacitance and 2mV/div sensitivity.
- Maximum 50ns/div unmagnified sweep.
- 20 MS/s digitizer and 100ns peak detect.

Will the 2230 display an X for diagnostic purposes? I do not
remember.

Only Channels 1 and 2 exhibit vertical linearity issues.

I haven't seen a case lately where U400 was *not* the culprit with these symptoms.

It's not abnormal for a higher BW 'scope to be a bit more noisy, resulting in a slightly thicker trace,

Raymond

In the 2400 series manuals, the table that defines the measurements for voltage and ripple state (for ripple measurement):

p-p Ripple at Two
Times Line Frequency

How is this supposed to be done? With a 60Hz line frequency (U.S.), is this supposed to be performed with the scope measuring the ripple triggered at 120Hz or am I misinterpreting what's being stated? Is it simply assumed that any ripple will present itself at twice the line frequency (full-wave rectification) and the scope being used to measure this will simply trigger at that frequency (assumedly using a fairly slow sweep speed to better see the waveform)?

Thanks,
Barry - N4BUQ

Hello to all again!
Jim Reese from Dayton, Ohio?back in action. I am going through the piles of stuff and have many 7K plugins available at low prices. All have had basic function testing in a 7704A unless otherwise noted. Add shipping from zip 45344.
7A16A, $207A18, $307A26, $407B50A, $307B51A, $357B92A, $50 7B92A non-working (short on power supply line, probably bad capacitor), $25
I have many others available that I have not gotten too yet that I will post later.? Let me know of anything you are looking for.
Regards,
Jim