Help with my 1st oscilloscope purchase...

Time for me to get my first oscilloscope and I have found what I’m hoping is a good Tek 465 on Ebay. This Tek is apparently in very good condition, comes w/ two sets of 10X probes, it was the personal scope of a university instructor from what the seller says. The seller has good feedback but also no idea what he has. I’m trying to figure out if I should take a chance on what seems like a pretty good scope.

I asked him if he would perform a test on the scope that I found here:

http://www.diyaudio.com/forums/showthread.php?postid=599653#post599653

Here is basically the test I asked him to perform from above thread:

1. Insert a probe into Channel A
2. Set VOLTS/DIV selector to minimal voltage. It should be something like 5mV
3. Set TIME/DIV selector to 0.5mS.
4. Channel A has pot for position. With this pot you shift the picture vertically.
5. There is another pot below the screen for Y axis.

With these two potentiometers you can adjust your picture into a visible part of the screen.

Touch the probe tip with your finger and if the scope is working you should se something on the screen. If not that doesn't necessarily means that the scope is not working. Try with channel B.

You can check whether your trigger is working properly or not. You have source switch at channel A trigger section. Switch it to EXT.line position. Set the volts/div selector to 50mV. Push the Trigger View button (the one between Channel 1 and 2 selector and you should see the sample of line voltage.

Here is his reply from the test –

”Hi,
I set it to what you specified and I saw a straight line, I touched the probe and the line went upwards. when I hit trigger the line jumped up to another grid line. What does this mean?
I can send pictures if you provide an email.”

Could anyone tell me if his test is in line and that this scope is performing correctly from the above test?

Thanks - Stan
 
It may be working, but I'd want to hear that a more-or-less sinusoidal 60Hz waveform was seen. Be aware that the 465 is getting quite old, and it suffers from hardened grease in the adjustments, and various other old-age ailments. Though they were real workhorses, they're heavy, hard to repair, and I wouldn't pay much for one, especially with the large number of newer scopes on eBay for a couple hundred bucks.
 
Sounds like the guy hit the "trigger view" button which essentially shrinks the whole picture so you can see where everything is.

There should be a calibration signal output somewhere on the front panel putting out something like 200mV or so at 1KHz. This should look pretty nice on the screen when triggered (auto/AC) A bit of edge peaking/rounding just means the probes need compensation (2mins w/ screwdriver.)

I have an old 465 that I love. The old Teks are VERY reliable in my experience.

Conrads right though, I wouldn't pay more than $100 tops.
 
When they're working, the Tek 2465 series has often been said to be the best portable analog oscilloscopes ever made. But they have an unobtainium Tek-custom IC that is prone to failure, in certain models.

The 2400-series scope models were killed after Tek sold their IC fab business to Maxim and Maxim then refused to produce such small quantities of ICs, for Tek's own equipment production.

You can read much more about all of the above in the archive of the TekScopes group, at http://www.yahoogroups.com .

Nevertheless, if you can get a good price on a working 2465, I would buy it. I have one, and really love it. It's just a joy, to use. Note that the 2465 is 300 MHz, while 2465A and 2465B are 350 Mhz and 400 Mhz.

On the other hand, if you can find something like a 2235 (100 MHz) that's cheap-enough, it might be a little safer buy. The quality doesn't seem quite as good as the 2400-series. But they're smaller and lighter, and usually quite easy to repair. I've repaired several of them (power supplies, mainly). They are very easy to use and perform very well. (You could probably find the slightly-enhanced military model, especially at http://www.govliquidation.com .) The other 2200-series are generally OK, too, although for the 2213 and 2215, I would only go with the "A" models, i.e. 2213A and 2215A, because of the unsatisfactory power supplies in the 2213 and 2215 non-A models.

The 475 is very nice, too, although it, like the 465, is getting somewhat old. However, like the 465, if you get lucky and get a good one, you won't be dissappointed! And a little Caig De-Oxit in the right places can work wonders. (Also, I have posted a blurb about cleaning the attenuator switch contacts, to try to fix the "fuzzy trace" problem in the later 400-series scopes, here: http://www.fullnet.com/~tomg/tekclean.htm . [But note that I forgot to mention the contacts that are on the _bottom_ of the board.])

It's too bad that the 7000-series mainframes are so bulky and heavy (i.e. shipping is expensive, and risky from most ebay sellers). They are great scopes, and are marvelously versatile, because of the plug-in architecture.