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Friday, June 29, 2018

Tektronix Oscilloscope, Model 2465A - *Updated*

Bit by bit, I'm slowly getting there.

I've purchased about $150 worth of parts that I'll be needing to make repairs - mainly capacitors and resistors.

The big item that I just bought though, is an older, but very high-end, oscilloscope.  I just won an auction for a Tektronix 2465A oscilloscope, for $200.  A photo of a 2465A is below.

In the mid 1980's, a powerful, high-end scope like this would have cost about $5000.  Pricing for some of this older test gear is quite reasonable, especially for the performance you get!  Of course technology has marched on, so while it's not obsolete, it's also not state-of-the-art, so depreciate the price to $200!

Edit:  Yep just found a 1988 Tektronix price list.

That $5500 dollars in 1988 would be $11,400 dollars in 2018, according to this website.  For $200 the scope would seem to be a steal...

The TekWiki (a wiki dedicated to Tektronix oscilloscopes) says this about the 2465 series:
The Tektronix 2465 is a four-channel 300 MHz portable oscilloscope. The 2465A is a 350 MHz scope, and the 2465B is the 400 MHz version.

It is the same as the 2467, except that the 2465 uses a conventional CRT while the 2467 uses a micro-channel plate CRT.

The 2465 is from the penultimate generation of analog Tektronix scopes.
Along the bottom right of the scope are four inputs for Radio Frequency (RF) signals.  Typically four channel scopes are pretty expensive, so this was also a great bargain in that respect.

I will soon be in possession of an "A" model, which has a 350MHz Bandwidth.  That's a fancy way of saying that it can't display signals accurately above that frequency.

Even though this scope is over 30 years old, it's still very solid, even today.  To purchase a modern four-channel oscilloscope able to resolve a 350MHz signal costs thousands of dollars.  The one below retails for $8500.  I don't have that kind of dough to spend on a hobby.
Now to be fair, the above scope has some really, really nice features that the older Tektronix doesn't.  For one thing, it's a storage oscilloscope - which basically means you can take screenshots and movies with it.  You can save that data to a USB stick or a hard drive.  That's pretty handy.  Also, as you may have noticed, the screen is multi-color, and the trend colors are linked to the color-coding of the channel inputs.

But for a difference of $8300 with the same specifications, I'll take the monochrome CRT, analog signal processing, and no storage.  Repair parts aren't too expensive either.

"What good is an oscilloscope?"  You might be saying that to yourself.  Well if you have a bit of electronics that isn't working correctly, this thing may be just what you need to identify the problem.

Below is a cool video from EEVblog, explaining just why O-scopes are so useful.  Watch and learn!

PS.

The older Analog Tektronix 2225 scope in the above video has a 50 MHz bandwidth, has two channels, and can be found at online auctions used for $100-$200.

The new Digital Rigol DS1054Z scope in the video also has a 50 MHz bandwidth, has four channels, and costs about $350 at Amazon.

Update #1:

The oscilloscope arrived a couple of days ago.  It still has tamper seals that read "calibration void if seal is broken".  Clearly the company that owned this instrument took excellent care of it, and ensured that it was always calibrated to a traceable standard.  Cool!


I cleaned off quite a bit of adhesive that remained from previous stickers that had once been on it.  Getting it clean took quite a bit of time, because I refused to use anything more aggressive than 50% isopropyl alcohol.  I've learned my lesson with harsh solvents on cosmetic surfaces.

I wasn't sure the scope would work properly, because the seller was this electronics recycling company.  In the online auction, they stated that it powered up, but that they don't have equipment to perform further testing.  On my end, this was a $200 crap shoot that the scope would work at all, let alone if all the channels would work correctly... 

And now, a few photos of *my own* Tektronix 2465A after I cleaned it up and took it to the work bench.

Below, about to have the moment of truth if I can only locate a power cord.

So far, so good.  The graticule lighting and dimmer knob work.

 All four channels are now enabled and show a trace.  Each trace can each be moved vertically, so all that stuff works.  The screen is bright, focused, and clean.  I was able to slow the traces down and make them scroll slowly by adjusting the big "sec/div" (Timebase) knob, so that also works.  The internal relays all click whenever it boots up or when you change voltage modes (rocker switches just above the CH1 and CH2 inputs).


Just a dark shot of the above picture.

Previous owner (before the recycle company) of this scope was Lockheed Martin Space Systems Corporation.  I would imagine that they took excellent care of their stuff!  I'm keeping the little decals for posterity.

I'm very pleased with this wonderful little scope!  I'm pretty confident it's a solid and functioning scope.  For $200 and a small shipping fee, it seems to be a winner.  Now I need to get a set of probes and a signal generator so that I can use it.

Update #2:

I purchased an inexpensive ($60) Chinese-made Radio Frequency Generator so that I could test out the oscilloscope.  As I had already guessed, the scope works just fine.

 I'm less impressed with the signal generator, (on the left) however.  The inputs to adjust the various RF output wave forms are 6 push buttons and one knob.  It took quite a while to fumble my way to getting a simple sine wave.  The interface is absolute crap.  It's intended to be controlled via a PC/USB interface - so now I need to get a laptop.  It's impossible to run this thing without having to consult the manual on what combinations of buttons to press every time I use it.


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