Test Equipment: Oscillocopes

[TinselKoala]

OK, that looks great! No there is nothing wrong with the "vertical lines", you are seeing a good fast risetime from your calibrator that's all. Now change the timebase to a faster value so you get just three or so cycles on the screen. Then you should be able to see the rising and falling edges of the squarewave pulse from the calibrator.

(Just leave everything else like you had it for now. The Delayed Timebase and all that is an "advanced functionality" so let's just get the basic controls down first.)

Don't push the intensity so far up that the bright places bloom out, that's not necessary. In general I like to run mine at the dimmest value that gives me a good picture. This will also help you get a sharp focus on the traces. These functions (intensity and focus) are generally High Voltage functions of the CRT display circuit.

I love those orange graticule illuminators! My old RM503 has a nice orange graticule and a blue persistent "photo-ready" phosphor so it really looks cool. Be careful about replacing with LEDs and resistors, sometimes this doesn't work because of the way Tek drives those lights from transistors. I'd recommend using the right bulbs here, they are generally available still.

Now let's try the second channel, with the same vertical amp settings as on the CH1. Just put the Vert Mode switch over to CH2, the Trigger Source to CH2, connect the calibrator to that channel input and let's see the trace from CH2.

Then if you got a good trace on CH2 you can try both traces at once, by patching the calibrator output to both channel inputs. Select "Alt" in the Vert Mode buttons for the dual trace display. Trigger on either CH1 or CH2 (if you got a good trace on CH2 before.)

Something to watch while you're eating....


http://www.youtube.com/watch?v=q55-CTCd2k4

[Brian516]

https://www.youtube.com/watch?v=C8WUWgIVG0A

says it will be done uploading in about 6 minutes.
Hopefully it's just some noise off the input.  It wasn't there before, though.


AHHH!  Now it's all just getting worse!!  I have a curved line on the screen when there is no input into it, and that noise wont go away. I tried different clip leads, different wire into the input jack, and even a probe.       I hate my life sometimes....

[TinselKoala]

Hmmm.... yes that's weird all right. Can you turn the CH2 input coupling to "ground" and see if that makes any difference? Also make sure you don't have any of the Delayed Timebase functions active. (Crank the Delay Time Postion knob fully CCW, make sure you have "A" selected on Horiz. Display buttons, and both A and B knobs on the Time/Div knob in the same position, with the red Var knob all the way CW and in the detent if there is one. ) I don't really think this will make much difference but let's check anyhow just to be sure.
Try changing the Trigger Source from Norm to CH1 and see if that affects the weirdness.

[TinselKoala]

https://www.youtube.com/watch?v=C8WUWgIVG0A

says it will be done uploading in about 6 minutes.
Hopefully it's just some noise off the input.  It wasn't there before, though.


AHHH!  Now it's all just getting worse!!  I have a curved line on the screen when there is no input into it, and that noise wont go away. I tried different clip leads, different wire into the input jack, and even a probe.       I hate my life sometimes....

No, that's good! That means it's probably a heat-related problem, and those can be tracked down with an approved "cold spray" applied to suspected components like transistors or capacitors that might be failing.  And the first thing to suspect is the power supply voltages. There is a good troubleshooting flowchart in the SM for checking the Power Supplies. With a little intelligent and careful guessing, and poking around with the approved cold spray, you may be able to find the tantalum capacitor that's causing the difficulty.... (just a guess at this point...)

I'd still like to know what the CH2 trace looks like, maybe after shutting down and letting it cool off for a while.

[TinselKoala]

Here's a link that has some good info and a paragraph or two specifically about the 465 and its tantalum caps:
http://www.repairfaq.org/sam/tshoot.htm#tshtek

And I +think+ this Cold Spray is probably OK to use, it's Freon 134 which didn't exist when the scope was made:
http://www.mgchemicals.com/products/dusters-cold-sprays/cold-sprays/super-cold-134-403a/