Re: What's the value of a C-12 camera: both the idea of what it can be used for, and is it worth anything more than being a door stop?
I have such a camera, somewhere.
The main problem with the camera is simply that you cannot find the film any more, although there are some companies that are trying to duplicate it.
The advantage of the camera is that it very nicely attaches to a 7000 series scope and provides a reasonable mechanical mount.
If I were to use it (and I have a digital scope that serves the same purpose), I'd carefully remove the lens, and machine a mount for a more or less standard digital camera.? I have a canon 35mm body that is not being currently used.? I think I'd have to use an extension ring to short focus (or a +1 or so closeup) to get a good picture of the scope screen.? I'd also have to integrate the camera's shutter system into the scope's sweep system (probably particularly important for the 7103/7104 system).
I think it's workable, but not trivial.? All I'd have left would be the mechanical mount, since the lens and film holder would be removed.
I'm not sure how valuable it is, on an individual, unmodified basis.? I haven't seen them go for much when I've run across them.
Harvey
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On 5/8/2022 2:19 AM, G Hopper, KB7WSD wrote: This last week I unexpectedly ended up with a odd collection of Tektronix stuff from an estate.
Among the eclectic collection, there was a Tektronix C-12 scope camera with what seems like two different scope bezels (I say appears because there is one attached to the camera and what I think is a second one that was attached to a 7834 that was used to hide the fact that the 7834 was missing the CRT.
When I googled about the camera I ran across a couple of different bits of information. One group of posts led me to believe that the bezels are still desirable and so shouldn't be considered trash. Another group of posts were generally on photography related sites and related that some people considered these scope cameras desirable for use in taking odd photos of odd things.
Another use I noticed was modification by removing the cartridge back and replacing it with a digital camera of various kinds.
I talked to Dennis Tillman about this and in the end, his conclusion was that I should throw the question out to the group as there was no sure answer.
So, I'm left not sure what I should do with this thing. Keep it as a curio? Maybe modify it (though the couple of times in 40 years that I've ever taken a picture of a waveform, I've just used a tripod...) for scope use? Give it to someone I dislike as a white elephant gift? Or is it a gold plated treasure I should hang on to like Bilbo to the ring. ;-)
Thanks for any ideas anyone can offer.
73,
Grant
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Re: Fault Finding with a Millivolt Meter
Interleaved: On 5/8/2022 9:58 AM, James55 wrote: Certainly lots of food for thought.
Regarding millivolt testing, is it then correct to understand that the best general practice is to fault find without using the equipments supply, but by using a current limited bench PSU? Another question is, "is the millivolt testing used on all components, for example, how effective would this be on BJT's and FET's, or should they still be tested 'offline' or even out of circuit?" Or am I missing something? Using the equipment's supply would work if it's current limited, but I personally prefer an adjustable power supply with current limit.? It seems safer to me, and I have a lot more control over the current and voltage.? I might, for instance on a 15 volt supply, just set for a maximum of 5 volts.? The lower the voltage you can profitably use, the less "drain" by semiconductors. Transistors are testable by this method, but you may have problems figuring out whether or not the transistor is simply turned "on" all the way, or is actually shorted.? I'd be tempted to try and use this as an indication, but not proof.? A shorted IC, however, may simply get hot.? So if it's really shorted, this ought to work, if it's doing something else? results could be problematical.
I've not had any time this week for hands-on experimenting, but have a board here which is pulling the supply voltage down so shall try out the suggestions given today.
Ok, see how it works.? Remember that you want two point probing at the part itself.? anything else will be misleading. Marking the voltage on that color coded layout might be a good idea as well. Harvey
.. Had a look at the lock-in amplifiers, and yes, they are not cheap, but I'm intrigued.. Even more so that "you can whip one together for any given special purpose for under $15.00. I have done so many times"...
Where can we find details on that?
Anyway.
Thanks again all.
Onwards and upwards.
James
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Re: Fault Finding with a Millivolt Meter
Rather than a 555, you might use a function generator, possibly coupled with a stepdown transformer to increase the current.
Amplifier can be 2 stages (AC coupled) using a dual op-amp. Detection can be accomplished with a 4066 type quad switch with the control inputs driven by the function generator followed by a an op-amp stage to combine the switch outputs and provide a bit more gain.
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Re: What's the value of a C-12 camera: both the idea of what it can be used for, and is it worth anything more than being a door stop?
There is a constant but so far unanswered demand for older Polaroid peel apart film. The images are an art form in themselves, and many thousands of serious and talented photographers around the world want the rendition they provide. There are two problems that have to be met. First, the tooling to make the cartridges? was wrecked and would cost a great deal to rebuild, and is not considered profitable for the amount of film that would be purchased. Second, some of the chemicals used in the film are now considered too toxic for convenient use and disposal.? There are efforts to re-formulate the chemistry, but so far the results are poor. Even the new current production Polaroid? SX-70 and 600 series film packs aren't quite the same as the older ones, but they are constantly improving.
?? There are two possible films that could be adapted to the older cameras, but that? would require a bit of work.? Fuji Instax film would be the easiest because like the original peel apart film the image from the lens which is reversed is reversed again by the film to be correct.? Current Polaroid film has to be exposed via a mirror in the camera because the film does not make the reversal to correct.? Another issue is the lens in the Tektronix camera. It is designed to fill the image area of the Polaroid film, the largest Instax format is smaller and the entire screen would not be taken unless the width and height of the trace were reduced.
? Fuji film produced the Polaroid peel apart cartridges until about four years ago, and absolutely refuse to make them again despite a? steady demand. They also have refused to adapt the Instax process- which is selling very well- to the size of the older Polaroid cartridges. They have refused to sell the equipment that can produce the cartridges.? Analog photography is making a steady comeback, there are hundreds of thousands, maybe millions of vintage Polaroid cameras still in existance and viable, so the demand for replacement Polaroid cartridges will not go away. Whether someone will come forward and make the long term investment to produce the film again is unknown.
?????? Bruce Gentry, KA2IVY
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On May 8, 2022, at 4:42 AM, Brian via groups.io <brianas1948@...> wrote:
? Hi , I wish they had some value or use now that Polaroid film is not made in that size any longer - I have been in touch long ago with the current manufacturers of the Polaroid film , they didnt get the tools to make that type and its too expensive to start from scratch . I have 2 x C12 one with the projected graticule adapter complete with a set of the graticules , they have 500 series scope adapters .
Brian (UK)
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Re: Fault Finding with a Millivolt Meter
I must say, these lock-in amps are starting to sound like a super handy piece of kit.
So, as an example, a diy version might consist of a 555 timer ultimately connected to a loop pick-up, with some funky interface between the two?
Every day is a school day, and I now owe my gratitude to Ed Breya for bringing these devices to my awareness. These are clearly serious, professional pieces of kit, however it is easy to see their benefit for those running a repair business or where time is of an essence. As I have never worked in one, it may expalin my ignorance as to their existence.
James
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Re: Vintage Sampling versus Modern/Digital Oscilloscopes
Mr Leach, fine questions....
Have experience since 1967 with both tube and solid state analog and since 1992 with digital scopes.
1/ as the decades progress the BW required went up, and Tektronix was at the highest level of the genre.
2/ Tek 7104 is 1 GHz mainframe and achieves that with 7A29 plugins.
Tek 7904 is 500 Mhz mainframe. Best analog portable was 2465B, 2467B, 350..400 MHz, analog signal path but fly by wire.
2/ Many modern digital scopes have selectable 1 M Ohm or 50 Ohm inputs.
high Zo inputs are not used generally in WB as the shunt capacity dominates. Expect to use 50 Ohm Zo, with a Zo probe or FET, etc active probe.
3/ Sampling analog scopes 7A11, 7S11 etc are difficult to setup and easy to burnout the front end ( tunnel diodes and sampling bridges)
4/ Our experience with modern digital scopes is limited to the old tektronix TDS320 ( very early 1990s) and Yokogawa DL7440, 500 MHz
5/ the old tube scopes in 3xx, 5xx series have high power consumption and tend to DC drift.
Hopefully these notes are interesting to you
Bon Soir¨¦e
Jon
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Re: Fault Finding with a Millivolt Meter
Lock-in amplifiers are very useful when one can stimulate a system at a fixed frequency. They are capable of amplifying weak response in the presence of noise. In the simplest case, they consist of an AC amplifier followed by a synchronous detector which operates at the frequency of the stimulation. commercial lock-ins cover a wide fequency range and can have narrow band filters tuned to the frequency of stimulation. Often, even a bare-bones lock-in can provide impressive results when compared with simple amplification (microvolt or better sensitivity in the presence of broadband noise or DC fluctuations).
In the present case, the stimulus is an AC current (or DC modulated at a specific frequency) applied to the suspect power rail. A small loop pickup would have an induced voltage if it is near a circuit board trace carrying that current. The induced voltage (which may be only microvolts) is AC amplified by a large factor and input to a syschronous detector, driven at the stimulus frequency. The detector output would have a DC level proportional to the induced voltage (note that there is a phase dependence and quadrature detection can be very useful in some cases).
Note that this is not limited to a loop pickup. A hall effect sensor would work and even simply probing the trace voltage level might suffice.
Commercial lock-ins are general purpose instruments capable of operating over a wide frequency range and with filters designed to enhance sensitivity at the stimulus frequency. If the stimulus frequency is fixed, the instrument is much simpler.
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Re: Can't "calibrate" one channel of a 7A26
"In the cases I have come across (two or three, I didn't document everything as well as I should) the accompanying symptom is severe aberration on the edges of the square wave from the calibrator."
Thanks to all for the helpful thread. In re Roger's comment above, the offending channel is characterized by the "severe aberration" he mentioned.
A fellow TEK junkie and I have several ill 7A26s and plan to correct them with a group session in the coming week.
Will report back!
--
William, k6whp
"A friend told me to cheer up, things could be worse.
So I cheered up and, sure enough, things got worse!"
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Re: Fault Finding with a Millivolt Meter
Certainly lots of food for thought.
Regarding millivolt testing, is it then correct to understand that the best general practice is to fault find without using the equipments supply, but by using a current limited bench PSU? Another question is, "is the millivolt testing used on all components, for example, how effective would this be on BJT's and FET's, or should they still be tested 'offline' or even out of circuit?" Or am I missing something?
I've not had any time this week for hands-on experimenting, but have a board here which is pulling the supply voltage down so shall try out the suggestions given today.
.. Had a look at the lock-in amplifiers, and yes, they are not cheap, but I'm intrigued.. Even more so that "you can whip one together for any given special purpose for under $15.00. I have done so many times"...
Where can we find details on that?
Anyway.
Thanks again all.
Onwards and upwards.
James
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What broke? The cap or the body? How about a photo?
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On Sun, May 8, 2022 at 4:29 AM <amplitude@...> wrote: Hi everyone,
Today I cracked the fuse holder on my Tek 2245B trying, well, changing the
fuse. The plastic was already corroded and just broke in half. I fixed it
using an instant plastic glue but need to replace it for safety reasons.
Any suggestion as to what works best? Has someone come across this and is
there any commercial fuse holder that might fit the job? Please advise,
it¡¯d be a great help.
Thanks for reading,
BJ
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Re: What's the value of a C-12 camera: both the idea of what it can be used for, and is it worth anything more than being a door stop?
Hi , perhaps I should consider that but I already have several Tek C1001/2 cameras along with Cortex frame grabber cards so it seems a bit un-necessary although it might be a little more convenient as the pc would not be required all the time .
Brian (UK)
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On Sunday, 8 May 2022, 14:37:49 BST, Glydeck via groups.io <glydeck@...> wrote: Here is what I did with my C-12. I still find it useful. George On May 8, 2022, at 4:42 AM, Brian via groups.io <brianas1948@...> wrote:
? Hi , I wish they had some value or use now that Polaroid film is not made in that size any longer - I have been in touch long ago with the current manufacturers of the Polaroid film , they didnt get the tools to make that type and its too expensive to start from scratch . I have 2 x C12 one with the projected graticule adapter complete with a set of the graticules , they have 500 series scope adapters .
Brian (UK)
? ? On Sunday, 8 May 2022, 08:47:06 BST, Richard Knoppow <dickburk@...> wrote:?
What kind of back is on it?? Another way of asking if it took only Polaroid film or standard shot film? Someone is making some types of Polaroid film again? but it's quite expensive.? Sheet film is available in some sizes.? Should have a lens and shutter in it.? The lenses were optimized for the application and are not good general purpose lenses.? Don't know about the bezels.? I was young and slim the last time I used one. Sent from my Galaxy
-------- Original message --------From: "G Hopper, KB7WSD" <kb7wsd@...> Date: 5/7/22? 11:20 PM? (GMT-08:00) To: [email protected] Subject: [TekScopes] What's the value of a C-12 camera: both the idea of what it can be used for, and is it worth anything more than being a door stop? This last week I unexpectedly ended up with a odd collection of Tektronix stuff from an estate.Among the eclectic collection, there was a Tektronix C-12 scope camera with what seems like two different scope bezels (I say appears because there is one attached to the camera and what I think is a second one that was attached to a 7834 that was used to hide the fact that the 7834 was missing the CRT.When I googled about the camera I ran across a couple of different bits of information.? One group of posts led me to believe that the bezels are still desirable and so shouldn't be considered trash.? Another group of posts were generally on photography related sites and related that some people considered these scope cameras desirable for use in taking odd photos of odd things.? Another use I noticed was modification by removing the cartridge back and replacing it with a digital camera of various kinds.I talked to Dennis Tillman about this and in the end, his conclusion was that I should throw the question out to the group as there was no sure answer.So, I'm left not sure what I should do with this thing.? Keep it as a curio? Maybe modify it (though the couple of times in 40 years that I've ever taken a picture of a waveform, I've just used a tripod...) for scope use? Give it to someone I dislike as a white elephant gift? Or is it a gold plated treasure I should hang on to like Bilbo to the ring. ;-)Thanks for any ideas anyone can offer.73,Grant
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Re: What's the value of a C-12 camera: both the idea of what it can be used for, and is it worth anything more than being a door stop?
Here is what I did with my C-12. I still find it useful.
George
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On May 8, 2022, at 4:42 AM, Brian via groups.io <brianas1948@...> wrote:
? Hi , I wish they had some value or use now that Polaroid film is not made in that size any longer - I have been in touch long ago with the current manufacturers of the Polaroid film , they didnt get the tools to make that type and its too expensive to start from scratch . I have 2 x C12 one with the projected graticule adapter complete with a set of the graticules , they have 500 series scope adapters .
Brian (UK)
On Sunday, 8 May 2022, 08:47:06 BST, Richard Knoppow <dickburk@...> wrote:
What kind of back is on it? Another way of asking if it took only Polaroid film or standard shot film Someone is making some types of Polaroid film again but it's quite expensive. Sheet film is available in some sizes. Should have a lens and shutter in it. The lenses were optimized for the application and are not good general purpose lenses. Don't know about the bezels. I was young and slim the last time I used one. Sent from my Galaxy
-------- Original message --------From: "G Hopper, KB7WSD" <kb7wsd@...> Date: 5/7/22 11:20 PM (GMT-08:00) To: [email protected] Subject: [TekScopes] What's the value of a C-12 camera: both the idea of what it can be used for, and is it worth anything more than being a door stop? This last week I unexpectedly ended up with a odd collection of Tektronix stuff from an estate.Among the eclectic collection, there was a Tektronix C-12 scope camera with what seems like two different scope bezels (I say appears because there is one attached to the camera and what I think is a second one that was attached to a 7834 that was used to hide the fact that the 7834 was missing the CRT.When I googled about the camera I ran across a couple of different bits of information. One group of posts led me to believe that the bezels are still desirable and so shouldn't be considered trash. Another group of posts were generally on photography related sites and related that some people considered these scope cameras desirable for use in taking odd photos of odd things. Another use I noticed was modification by removing the cartridge back and replacing it with a digital camera of various kinds.I talked to Dennis Tillman about this and in the end, his conclusion was that I should throw the question out to the group as there was no sure answer.So, I'm left not sure what I should do with this thing. Keep it as a curio? Maybe modify it (though the couple of times in 40 years that I've ever taken a picture of a waveform, I've just used a tripod...) for scope use? Give it to someone I dislike as a white elephant gift? Or is it a gold plated treasure I should hang on to like Bilbo to the ring. ;-)Thanks for any ideas anyone can offer.73,Grant
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Re: What's the value of a C-12 camera: both the idea of what it can be used for, and is it worth anything more than being a door stop?
Hi , I wish they had some value or use now that Polaroid film is not made in that size any longer - I have been in touch long ago with the current manufacturers of the Polaroid film , they didnt get the tools to make that type and its too expensive to start from scratch . I have 2 x C12 one with the projected graticule adapter complete with a set of the graticules , they have 500 series scope adapters .
Brian (UK)
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On Sunday, 8 May 2022, 08:47:06 BST, Richard Knoppow <dickburk@...> wrote: What kind of back is on it?? Another way of asking if it took only Polaroid film or standard shot film? ?Someone is making some types of Polaroid film again? but it's quite expensive.? Sheet film is available in some sizes.? Should have a lens and shutter in it.? The lenses were optimized for the application and are not good general purpose lenses.? Don't know about the bezels.? ?I was young and slim the last time I used one.?Sent from my Galaxy -------- Original message --------From: "G Hopper, KB7WSD" <kb7wsd@...> Date: 5/7/22? 11:20 PM? (GMT-08:00) To: [email protected] Subject: [TekScopes] What's the value of a C-12 camera: both the idea of what it can be used for, and is it worth anything more than being a door stop? This last week I unexpectedly ended up with a odd collection of Tektronix stuff from an estate.Among the eclectic collection, there was a Tektronix C-12 scope camera with what seems like two different scope bezels (I say appears because there is one attached to the camera and what I think is a second one that was attached to a 7834 that was used to hide the fact that the 7834 was missing the CRT.When I googled about the camera I ran across a couple of different bits of information.? One group of posts led me to believe that the bezels are still desirable and so shouldn't be considered trash.? Another group of posts were generally on photography related sites and related that some people considered these scope cameras desirable for use in taking odd photos of odd things.? Another use I noticed was modification by removing the cartridge back and replacing it with a digital camera of various kinds.I talked to Dennis Tillman about this and in the end, his conclusion was that I should throw the question out to the group as there was no sure answer.So, I'm left not sure what I should do with this thing.? Keep it as a curio? Maybe modify it (though the couple of times in 40 years that I've ever taken a picture of a waveform, I've just used a tripod...) for scope use? Give it to someone I dislike as a white elephant gift? Or is it a gold plated treasure I should hang on to like Bilbo to the ring. ;-)Thanks for any ideas anyone can offer.73,Grant
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Hi everyone,
Today I cracked the fuse holder on my Tek 2245B trying, well, changing the fuse. The plastic was already corroded and just broke in half. I fixed it using an instant plastic glue but need to replace it for safety reasons.
Any suggestion as to what works best? Has someone come across this and is there any commercial fuse holder that might fit the job? Please advise, it¡¯d be a great help.
Thanks for reading,
BJ
|
Re: What's the value of a C-12 camera: both the idea of what it can be used for, and is it worth anything more than being a door stop?
What kind of back is on it?? Another way of asking if it took only Polaroid film or standard shot film? ?Someone is making some types of Polaroid film again? but it's quite expensive.? Sheet film is available in some sizes.? Should have a lens and shutter in it.? The lenses were optimized for the application and are not good general purpose lenses.? Don't know about the bezels.? ?I was young and slim the last time I used one.?Sent from my Galaxy
toggle quoted message
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-------- Original message --------From: "G Hopper, KB7WSD" <kb7wsd@...> Date: 5/7/22 11:20 PM (GMT-08:00) To: [email protected] Subject: [TekScopes] What's the value of a C-12 camera: both the idea of what it can be used for, and is it worth anything more than being a door stop? This last week I unexpectedly ended up with a odd collection of Tektronix stuff from an estate.Among the eclectic collection, there was a Tektronix C-12 scope camera with what seems like two different scope bezels (I say appears because there is one attached to the camera and what I think is a second one that was attached to a 7834 that was used to hide the fact that the 7834 was missing the CRT.When I googled about the camera I ran across a couple of different bits of information.? One group of posts led me to believe that the bezels are still desirable and so shouldn't be considered trash.? Another group of posts were generally on photography related sites and related that some people considered these scope cameras desirable for use in taking odd photos of odd things.? Another use I noticed was modification by removing the cartridge back and replacing it with a digital camera of various kinds.I talked to Dennis Tillman about this and in the end, his conclusion was that I should throw the question out to the group as there was no sure answer.So, I'm left not sure what I should do with this thing.? Keep it as a curio? Maybe modify it (though the couple of times in 40 years that I've ever taken a picture of a waveform, I've just used a tripod...) for scope use? Give it to someone I dislike as a white elephant gift? Or is it a gold plated treasure I should hang on to like Bilbo to the ring. ;-)Thanks for any ideas anyone can offer.73,Grant
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Re: Help with diagnosis of Tek 2465 Power Supply Problem
Hi Luca, On Sat, May 7, 2022 at 10:16 PM, lpb612 wrote: ....
Vin in 0 pulse(-240, 0, 10u, 0, 0, 12u, 24u) Here you are applying 240V ripple at the voltage sense network. Q1050 connects/disconnects T1050 pin 2 and, another winding at pin 5 is connected through CR1050 to your node "in". Although we don't have the parameters of the transformers T1050 and T1060, it is almost certain that when Q1050 turns off magnetic energy in T1050 creates a current in CR1050 and current still continues to flow into your "in" node while Q1050 is off. There will be continuous current, with some ripple, either from Q1050 or CR1050. The ripple voltage showing up at bottom of R1046 is probably much smaller. I haven't measured the ripple so I don't have a concrete number. It is also a difficult measurement to make safely, connecting scope probe ground to any of the nodes inside the PSU needs isolating the PSU and even isolating the scope. I assume you are already aware of the internal connection between your scope probe's signal ground and the earth terminal of the power plug. Without isolating the PSU you would be shorting any node scope ground touches to earth. There are special probes with HV isolation for this purpose. Ozan
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What's the value of a C-12 camera: both the idea of what it can be used for, and is it worth anything more than being a door stop?
This last week I unexpectedly ended up with a odd collection of Tektronix stuff from an estate.
Among the eclectic collection, there was a Tektronix C-12 scope camera with what seems like two different scope bezels (I say appears because there is one attached to the camera and what I think is a second one that was attached to a 7834 that was used to hide the fact that the 7834 was missing the CRT.
When I googled about the camera I ran across a couple of different bits of information. One group of posts led me to believe that the bezels are still desirable and so shouldn't be considered trash. Another group of posts were generally on photography related sites and related that some people considered these scope cameras desirable for use in taking odd photos of odd things.
Another use I noticed was modification by removing the cartridge back and replacing it with a digital camera of various kinds.
I talked to Dennis Tillman about this and in the end, his conclusion was that I should throw the question out to the group as there was no sure answer.
So, I'm left not sure what I should do with this thing. Keep it as a curio? Maybe modify it (though the couple of times in 40 years that I've ever taken a picture of a waveform, I've just used a tripod...) for scope use? Give it to someone I dislike as a white elephant gift? Or is it a gold plated treasure I should hang on to like Bilbo to the ring. ;-)
Thanks for any ideas anyone can offer.
73,
Grant
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Re: Help with diagnosis of Tek 2465 Power Supply Problem
Fig 13 is the open loop frequency response. You need to consider the feedback network R1033/C1033/R1036 in addition to the amp. You could put it in
NGSPICE to look at the closed loop response. C1035 does additional filtering as you also mentioned. I did the simulation with the R1036, C1035, C1033, R1033 considered. It seems that there is still sufficient ripple at the input of error amplifier. At the input, the ripple is about 1Volt, which is too large for the error amplifier to produce at its output a signal level that is more or less in the middle. I also did analysis of the frequency response of the circuit. The frequency response from REF to output of Error Filter is like: [R3/(R1*R2*C1)] (s+z1)/[s * (s+p1)] where R1 = R2 = 10K Ohm, C1 = 4700pF, z1=1/ (R3*C2), p1 = 1/(C1(R1||R2) R3 = 100K Ohm, C2=4700pF. So from 0 frequency to about 338Hz, it behaves like an integrator. From 338Hz to 6772Hz, it is a constant gain, from 6772Hz, it decades again at slope -1 like an integrator. At about 40KHz, the switching frequency, the gain magnitude is about 0.8 (linear). This is consistent with the simulation that there is significant ripple. I managed to blow up TL494 on the scope by not connecting the 2 Ohm load as suggested. I have ordered new ones, and will be install replacement so that I can measure the voltage. I totally get the U1371C action. What I don't understand is how the AC ripple gets filtered out in the control loop so that the control at normal working condition is really slow control loop (say a few hundred Hz), and not happening at the switching frequency (40KHz). In other words, the error amplifier output will be a slowly changing signal at a level about half of the PWM triangle peak. Thanks, Luca PS. The simulation program is attached below. I used 741 Opamp as an example. * Tek 2465 regulator error filter Vin in 0 pulse(-240, 0, 10u, 0, 0, 12u, 24u) C1072 in 1072 3.3uF D1072 0 1072 Diode R1046 in zeroV 240K R1045 VREF zeroV 10K VREF VREF 0 5V C1035 zeroV 0 4700p IC=0 R1036 zeroV FB 10K C1033 FB RC 4700p IC=0 R1033 RC PWM 100K Dopamp out PWM Diode * Amplifier model - commented out as it is not working * E1 out 0 0 FB 1000 * Dclamp1 out Clamp1 Diode * Rclamp1 Clamp1 VREF 10 * Dclamp2 Clamp2 out Diode * Rclamp2 0 Clamp2 10 * Error amplifier treated as 741: +input -input +PS -PS output .INC UA741.lib Vcc Vcc 0 12V Vee Vee 0 -12V XIC1 0 FB Vcc Vee out UA741 .MODEL Diode D * .probe alli .control tran 1us 2ms plot v(in)/100 v(out) plot v(fb) v(zeroV) .endc .END
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Re: 2232 Scope; What am I seeing?
Harrison,
What you describe is likely bad filter condensers and possible bad rectifier diodes. The condensers should be a high temp type, low ESR and long life type such as Nichicon ULD, UHE, UCY or LGR. The capacitance can be raised, e.g. 1000mfd to 1200 or 1500mfd. The diodes for the 30 and 100V supplies can be replaced with 1N4937. The other diodes can be raised to 3A types at 400V or higher. The voltage rating of the originals is 400V. These MUST be very fast switching types since it is a high frequency power supply. The preregulator circuit can be suspect. The 100,000 ohm resistor, R926, should be 2W. The RIFAs must be replaced with new safety caps of X1/Y1 or X2/Y2 types. It is possible the high voltage multiplier is bad. These are the things most common that will cause your ticking problem.
Mark
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I don't have specific experience with removing a CRT on TEK scopes, but do have quite a bit on HP o-scopes. What I have found there is usually a rubber or foam shock absorbing gasket around the neck or near the face of the CRT (inside the MU metal shield) has formed a bond between the CRT and shield.? I have had to slice around the tube or shield with a flat blade, ie. putty knife to break the bond. On the HP o-scopes the foam/gasket was usually only an inch deep.
Don Bitters
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James55
Jean-Paul
k6whp
Michael A. Terrell
Brian
Glydeck