0

I have an old Protek P-3502C Oscilloscope that I picked up second hand from my school. It has proven to be a great way to learn how to use oscillocopes, and has helped me with diagnostics as well.

But for as long as I have had it, I have had no clue what a couple of things on it are.

The first off is a section labeled COMP. TEST It has a single banana jack, and a button labeled in and out. (see image).

The other thing is two holes on the botton labeled CH A STEP BAL and CH B STEP BAL. (see image) From what I can tell from this document, it keeps the line from jumping around when I vary the volts/div scale. Is that correct?

COMP. TEST Connection

Comp Test

STEP BAL Holes

BAL

BarrowWight
  • 203
  • 1
  • 11
  • @EugeneSh. So it basically keeps the line from shifting when I change the Y axis scale – BarrowWight Jun 21 '17 at 18:24
  • I would guess the "COMP TEST" is a probe compensation tester. If you touch the probe to the inside of the jack, does a square wave appear on the screen? EDIT: Don't do that. It's actually a component tester. http://phys114115lab.capuphysics.ca/App%20J%20-%20oscilloscope/Osc%20Protek.htm – Chris M. Jun 21 '17 at 18:24
  • @ChrisM. No Square wave, I have a .5V 1khz can line on the oscilloscope as well, but there is a sine wave if the button is pressed in. – BarrowWight Jun 21 '17 at 18:28
  • @ChrisM. Well I probed it, what do I do with that port. – BarrowWight Jun 21 '17 at 18:30
  • Looks like you can put a diode, cap, resistor, or transistor between that port and the ground terminal and the scope will show you an I-V curve on the screen. Just touching the probe to the port shouldn't do anything. – Chris M. Jun 21 '17 at 18:39
  • @ChrisM. I just figured it out myself. Pretty neat. Any clue what the in/out button is for? (Besides turning off the waveform) – BarrowWight Jun 21 '17 at 18:42
  • I think it toggles the scope between component test and normal operation. Component test would, I think, be "out" (scope provides the signal), and scope would be "in" (scope measures the signal). – Chris M. Jun 21 '17 at 18:44
  • Let us [continue this discussion in chat](http://chat.stackexchange.com/rooms/60852/discussion-between-user173724-and-chris-m). – BarrowWight Jun 21 '17 at 18:47
  • HP and Tek never needed that option, so I have to think it is part of the cheap scope calibration. Normally a 1vpp square wave is the test signal is used to calibrate probes this may be for the vertical amp. in/OUT. You'll figure it out. More useful is the B invert and A+B mode with two probes calibrated and flat lined on same signal to ensure 0V in A_B mode then move one probe to get drop voltage and read current etc. – Tony Stewart EE75 Jun 21 '17 at 18:56

1 Answers1

3
COMP. TEST

This is a simple component tester. Just connect up the component(s), set channel A for 2V / div, channel B for 5V / div and press the button. You can see the capabilities here:-

  Circuit      Large      Medium      Small

testing

Not sure of the value of this feature these days with disposable parts. Modern scopes don't have them.

Paul Uszak
  • 7,327
  • 5
  • 37
  • 69
  • Someone in commends clarified this, can you add a little bit about step balance, and I will mark this as correct. – BarrowWight Jun 22 '17 at 03:07
  • This is a fairly limited version of the test capabilities of something like a Huntron Tracker, for in-circuit, power off tests of things. Huntron has a good write up on exactly how it works here: http://www.huntron.com/sales-support/pdf/ASA-paper-extract.pdf – R Drast Jun 22 '17 at 11:51
  • @user173724 No, sorry. That's all I've got unfortunately. What about half a tick? Up vote some of my other answers? I will add this though. My Hameg 203 is old and analogue but doesn't have these _step_ adjustments. So only some 'scopes have them... – Paul Uszak Jun 22 '17 at 22:23