Testing older oscilloscopes

[Bob M.]

Recently, I became the recipient of two older Tektronix oscilloscopes, both Model 466, from a closed down electronics lab. I'm wondering if anyone can point me in the right direction so I can test these out to see if they are in any kind of working order and to see if their calibration is close or not. I don't usually use oscilloscopes so I'm behind the curve. They both power up.

Under the Model 466, it says Storage Oscilloscope - I wonder what that refers to?

Thanks in adv,

Bob M.

[nevetslab]

Tektronix 466 Portable Storage Scope

Recently, I became the recipient of two older Tektronix oscilloscopes, both Model 466, from a closed down electronics lab. I'm wondering if anyone can point me in the right direction so I can test these out to see if they are in any kind of working order and to see if their calibration is close or not. I don't usually use oscilloscopes so I'm behind the curve. They both power up.

Under the Model 466, it says Storage Oscilloscope - I wonder what that refers to?

Thanks in adv,

Bob M.

070-2037-00_466-464+DM44Operators_Feb82.pdf

I'd start with reading thru the attached Instruction Manual for the Tek 466 Storage Scope. While I don't own a 466, my bench scope is a Tektronix 7633 Storage Scope, which unlike the dedicated format of the 466, this 7000 series scope is a mainframe instrument, allowing selection of a wide variety of vertical plug-ins, as well as different time base plugins. The storage facility uses a phospher screen that takes a little getting used to, as you're burning the image onto a separate mesh screen to display the captured image. The basic mode in non-storage, is like any other scope. It has a very stable triggering system, using AC line sync, internal signal, selectable for either Ch 1 or 2, as well as external sync....used to keep the display stable.

There's a basic tutorial in the manual to walk you thru the instrument.

In my recent post SWR SM900 Fan Circuit issues (older series) in Maintenance, Troubleshooting & Repair, the scope photos used in that thread were all captured using the storage facility on my 7633 scope. Very useful in single-triggered-sweep captured image (have to be quick with the Save button so the image doesn't get erased by another sweep). In those, I just used an old Sony digital camera to take a snap shot of it. Normally, trying to take a picture of what appears to be stable to our eyes, from the repetitive sweep rate, the camera will only catch a portion of the image on the screen. Storing it on the phosphor screen lets me get all of the image without the camera's effective shutter speed.

[Bob M.]

[ATTACH]54655[/ATTACH]

I'd start with reading thru the attached Instruction Manual for the Tek 466 Storage Scope. While I don't own a 466, my bench scope is a Tektronix 7633 Storage Scope, which unlike the dedicated format of the 466, this 7000 series scope is a mainframe instrument, allowing selection of a wide variety of vertical plug-ins, as well as different time base plugins. The storage facility uses a phospher screen that takes a little getting used to, as you're burning the image onto a separate mesh screen to display the captured image. The basic mode in non-storage, is like any other scope. It has a very stable triggering system, using AC line sync, internal signal, selectable for either Ch 1 or 2, as well as external sync....used to keep the display stable.

There's a basic tutorial in the manual to walk you thru the instrument.

In my recent post SWR SM900 Fan Circuit issues (older series) in Maintenance, Troubleshooting & Repair, the scope photos used in that thread were all captured using the storage facility on my 7633 scope. Very useful in single-triggered-sweep captured image (have to be quick with the Save button so the image doesn't get erased by another sweep). In those, I just used an old Sony digital camera to take a snap shot of it. Normally, trying to take a picture of what appears to be stable to our eyes, from the repetitive sweep rate, the camera will only catch a portion of the image on the screen. Storing it on the phosphor screen lets me get all of the image without the camera's effective shutter speed.

nevetslab,

Thanks very much for that informative manual and the fine explanation of the storage mode.

Bob M.

[Jazz P Bass]

The 'storage mode' is a crude capture of the glowing phosphor.

I have used one for 'capturing' timing events.

Pretty much not needed for guitar amp work.

[J M Fahey]

Normally, trying to take a picture of what appears to be stable to our eyes, from the repetitive sweep rate, the camera will only catch a portion of the image on the screen.

Old style mechanical cameras had that problem because obturator was open only for a brief fraction of a second, often 1/60th , 1/125th and so on and of course will capture only that portion of a sweep.

Solution was to close diaphragm as much as possible, F16 or even F22 if available and use a *long* exposure time; 1/8th of a second or slower, most cameras providing down to 1 second which is more than enough for most anything (except perhaps an ECG sweep).
It has the added bonus of much increased depth of field so uncritical focusing and making lens sharper.

Digital cameras are completely different but tend to mimic old mechanical cameras because of familiarity but also because they are more "intuitive".

Exponential "power of 2" mechanical camera settings are in fact best to match logarithmic eye response to light.

[nevetslab]

Old style mechanical cameras had that problem because obturator was open only for a brief fraction of a second, often 1/60th , 1/125th and so on and of course will capture only that portion of a sweep.

Solution was to close diaphragm as much as possible, F16 or even F22 if available and use a *long* exposure time; 1/8th of a second or slower, most cameras providing down to 1 second which is more than enough for most anything (except perhaps an ECG sweep).
It has the added bonus of much increased depth of field so uncritical focusing and making lens sharper.

Digital cameras are completely different but tend to mimic old mechanical cameras because of familiarity but also because they are more "intuitive".

Exponential "power of 2" mechanical camera settings are in fact best to match logarithmic eye response to light.

It may be this 'dinosaur' of a Sony Mavica camera that I've been using mimics the shutter speed issues enough so that taking a picture of multiple sweeps, or dual displays on a spectrum analyzer that shows, say, average spectrum and peak spectrum, what the digital camera displays is incomplete......large chunks of the visual display my eyes see are missing. I get the same thing with the scope photos, particularly when displaying two or more traces. At some point when I have funds to spend, I'll move beyond this stupid camera. My digital scopes are too large for the bench (LeCroy 7200A, Analogic 6100B), so I continue living with the Tek 7633 and it's phosphor storage capability, and have bent it to my needs.

I do disagree with Jazz, regarding it not needed for guitar amp work. Works wonderful for capturing very short term events, such as current inrush behavior or watching the grids of power tubes on a Fender amp that is popping or thumping far more than normal. My digital scopes also do a wonderful job in that, but, just no space for them, nor no budget for the current technology occupying small footprints.

[J M Fahey]

Many mechanicasl camera shutters had an extrat "T" labelled setting,meaning "time".

You push it through a flexible remote trigger to avoid vibration and you keep it pushed as long as you wish.

Among other uses, very good to catch aerial fireworks or night pictures and of course, for sllloooowwww scope sweeps .... even if phosphorous had no persistence at all.

Some went even one further step and had an extra Click ON ..... as long as you want, even all night ... click OFF setting.
Good for Astronomical photography to catch **faint** stars.