Did I break my scope probe?

[Nikolas Britton]

Hello all,

I just got my first oscilloscope today, a Tek 2213, off ebay and was
playing with it most of the day using ether the probe adjust signal or
signals from my computer's sound card. The square waves from the probe
adjust where square and the sine, square, sawtooth, etc. waves from my
computer where as they should be too, everything was working fine!

Then... I decided I wanted to clean the unit...
The first thing I do is take off the pouch bag on top by removing the
two screws that hold the plastic back piece on, one more screw later I
had the blue case off to look inside the unit. I got the case back on
and then give the front panel a rub down with isopropyl alcohol and
Qtips. After fully dismantling the probe I did the same to it, the
probe is a "Tek p6006 BNC 3.5 / 10x = 7pf. 10M-Ohms"

After I get everything back together and turned the unit on I tested it
with the probe adjust signal, the square wave was not square, It has a
triangular spike at the top / beginning of the wave and the inverse at
the end / bottom of the wave. I switched the probe to the other
channel... same thing... test it with my PC... only thing that looks
normal is the sine wave*. After all that I connect another probe that
came with the unit, an old looking and worn out RCA WG401A. Everything
seems to be ok again.

What did I break???

*sorry forgot, If I remember right... I can flip the switch from AC to
DC that's on the vertical mode panel and the wave becomes (more) square.

 

[Nikolas Britton]

Does this have something to do with adjusting the compensating
capacitor in the probe, is the p6006 adjustable, do you twist the probe
until the square wave is square?

I guess if thats true then it would make sense that the probe adjust
signal is all out of wack because I dismantled the probe and then when
I put it back together I didn't compensate it, yes I'm a total newbie
with scopes.

 

[Adrian Brentnall]

HI Nikolas

Does this have something to do with adjusting the compensating
capacitor in the probe, is the p6006 adjustable, do you twist the probe
until the square wave is square?

I guess if thats true then it would make sense that the probe adjust
signal is all out of wack because I dismantled the probe and then when
I put it back together I didn't compensate it, yes I'm a total newbie
with scopes.

I'm not familiar with that specific model of probe - the ones I've
used have a small 'screw-head slot' in the body of the probe that you
tweak with (ideally) a non-metallic tweaker unti a square wave looks
square.

On my old Hameg scope there's even a handy 'calibration' output on the
front panel, so you can just hang the probe on there & adjust it.

Certainly sounds like you've accidentally 'adjusted' the scope probe -
now all you need to do is find out how to set it back <g>

Good luck
Adrian
Suffolk UK

======return email munged=================
take out the papers and the trash to reply

 

[Dave Plowman (News)]

After I get everything back together and turned the unit on I tested it
with the probe adjust signal, the square wave was not square, It has a
triangular spike at the top / beginning of the wave and the inverse at
the end / bottom of the wave.

The probe should have an adjustment on it for precisely this reason.

 

[Jim Yanik]

Does this have something to do with adjusting the compensating
capacitor in the probe, is the p6006 adjustable, do you twist the probe
until the square wave is square?

I guess if thats true then it would make sense that the probe adjust
signal is all out of wack because I dismantled the probe and then when
I put it back together I didn't compensate it, yes I'm a total newbie
with scopes.

On that model probe,the main probe body is screwed in or out to adjust
compensation,then the collar is screwed to lock the probe body in place.
That probe was originally designed for use with earlier 500 series tube
scopes,but is perfectly usable for your model.The hook tips and some other
accessory tips are less useful for modern circuitry,though.

 

[Nikolas Britton]

Thank you all, The metal insert for the variable cap was stuck inside
the probe. I had to pull it out with a small pair of long needle nose
pliers and reattach it to the other end of the probe, then I
compensated it. Everything is working fine again.

Thanks.