found bell&howell oscilloscope

[toybox]

dont know if it works but i seen on some sight saying it was just a piece of crap i dont know is it worth messing around with free but i know nothing about oscilloscopes!also got a kinda neat tube multimeter

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[RF]

Any scope is better than no scope

Re: what others say - Bah! You are just going to look at some audio waveforms anyway...right?
My first scope was a really old Eico single trace - worse than this one you found. I had a lot of good use out of it.
Hope it works.

bruce

[toppobrillo]

the scope is a heathkit, much like the one i used for a while. 2MHz only i believe. you need a probe to test with [you can use an aligator clip/a piece of wire to test it] -it should have a calibration signal available on the front panel.
not junk! if it works, it works. good find.

edit: i see you have some kind of probe, but hey i see no trace- did you try to find it?

[toybox]

dont even know where to begin trying to test it .i can get it to power up that is about it. it has a input with a 2"wire and two alligator clips but the wire looks not vary good

[toybox]

how do i go about trying to find the trace?

[andrewF]

[toybox]

Ok now i have a green line going vertically down the middle of the screen but it sure is nice to see something

[andrewF]

sounds promising
set the brightness, so you can see it easily but no stronger.

try connecting up a LFO or VCO output to the inputs and see if you can get a trace happening, tweak the controls to get a good image...if any. Don't worry about using a probe for now, any wires to make the connection will do the job (at least to test the thing).

[RF]

[toybox]

Ok got a little dot scrolling form left to right now tried breadboarding a simple 555 thing and poked around with the alligator clip input thingy to the output
but did not see any change this has become vary educational to me seeing that iv never had touched a oscilloscope before still dont know wht all the switches are for but i need to give thanks!! to everyone helping me along the way to figuring it out im getting hopeful that stuff will all mash together

[toppobrillo]

so now adjust the horizontal sweep. maybe called "time/division" it's a big rotary switch with time based incremental steps. click it over to the right [clockwise] and the dot scrolling should become a horizontal bar.

on the input, near where the probe plugs in, there should be a 3-position switch that reads AC/GROUND/DC. this is the input coupling. switch it to ground and adjust the vertical position knob to put the trace where you want it.

switch it to DC and connect the probe to a voltage source and see that the vertical scaling [volts-per-division] is at least close. i.e. at 5V/Division, a 15V+ input should be 3 squares up from where the trace sits at ground.

you know, there is actually, now that i think about it, probably a user's manual around somewhere. do a search for the model number and see.

josh

[Blue Hell]

If possible please post a better picture of the front panel of the scope (with readable text), it would be easier to talk about it that way.

Meanwhile the idea of a scope is not too complicated. Basically it is CRT that can steer a dot in all directions (usually out of the visible view as well, but it should have some visible glow then at least).

You have a time base that makes the beam run at a steady speed from left to right, and when it arrives there it will be swept back to the left very fast and it will be turned off during that action. Then it repeats. To control the speed you have time base control that is marked in time per (horizontal) division.

The input signal controls the vertical movement of the beam, when the input signal is positive the dot moves up, when it's negative the dot moves down. The sensitivity of this input can be set by a control marked with Volts per division. Usually you can choose the input to be disconnected (GND), coupled AC or coupled DC.

The timebase should roughly be at a speed comparable to how fast your input signal changes, when too slow you see no change and when too fast it smears out in the vertical direction.

So when you have the dot visible, basically you tweak the input sensitivity and the timebase speed till you get a picture of the signal. Usually that signal will not stand still then, and that is where the next trick comes in, triggering.

The trigger mechanism compares the input signal to a set limit, and when it crosses that limit it will immediately (well, not quite, but that's the basic idea) start the trace flyback operation instead of waiting till the beam reached the right side of the display. This will cause the horizontal movement of the trace to be synchronized to the signal, making the image stand still (when there is a repeating input signal that is).

There usually are two controls for the trigger trickery, the trigger level and the trigger direction. the level control is used to make a still image and with the direction control you select if you start with the up going or the down going part of the signal.

Sometimes there are some extra settings for triggering, like low speed, high speed or complicated signals (like TV signals), depending on the actual signal one of those settings will probably work best.

Well that's the basics, hope it will help in way

[toybox]

here is a better pic well at least better then the cell phone pic

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[frijitz]

[toybox]

Ok got some movement .sorry for the bad pic now i just need to learn how to use this to my advantage. thanks frijitz i kinda fell dumb yesterday i was franticly flipping switches not giving it any time

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[frijitz]

[Danno Gee Ray]

Try this link for some useful info:

http://courses.ncsu.edu:8020/ece480/common/htdocs/scope1.htm#AA

or maybe this PDF:

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[toybox]

Thank you!!!this will give me some reading to do cant play around with any thing right now because im sick with the cold from hell

[RF]

Glad you got it working, Toybox

Once you start using it - especially in troubleshooting a circuit - you'll wonder how you ever got by without one....