Help with techtronix 465B scope what to do

[sam67]

Just got a techtronix 465B scope with a x10 probe but don't have a clue how to set it up right to get a trace..

I feel gutted as i thought i would try to see how a scope works and thought i would be able to set this up correctly but to be honest i don't have a clue with it and feel i have got in way over my head .

I have the manual and set some of the controls but there are so many dials that i am not 100% it's set right and the manual is not that helpful for me..

I am not to bad usually at following things but for some reason i feel a right dumb ass with this .

I did read up on scopes before i got this but thought i would be able to work one,well that just shows you how wrong i was.

So i am now at a loss because i would like to make sure this is working correctly which i think it is as the ebayer shown it to be working and it is just me that does not know how to work it correctly..

Where did most of you guys learn to use these kinda test equipment because the school i went to never did anything to do with electronics ..i did not even know ohms law till i searched the net ..Just shows how some people are more fortunate to learn .I feel well and truly robbed of my education as i now learn that being in mainstream schooling has now affected my outcome on some things later on in life.

Sorry guys for the self pity but reality has finally struck home.Maybe any newbies like me that try to run before they can walk might consider what they can and cannot do before they spend there hard earned cash.

[stj]

Re: Help with techtronix 465B scope what to do

http://www.ionpool.net/arcade/scope_files/scope.html

[sam67]

Re: Help with techtronix 465B scope what to do

Thanks Stj,

I have now managed to get the trace looking at the link you provided ,Here is a pic of the scope ...The trace looks better than in the pic due to the light...But if anyone can help me to set this up better if i have missed some thing then it would be great.

Now what would be the recommended settings to look at some of the components in my faulty psu that has intermittent problem..Can i use these settings in the pic to look at the main filter cap for ripple or check on the pwm ic that i have the data sheet ? just so i can get an idea how the scope is doing.

Any help appreciated as i am trying not to give up even with my limited knowledge .

ps i have changed the setting to DC coupling on the left side which is in AC on the pic..i only noticed once i looked at the pic lol

[Dgtech]

Re: Help with techtronix 465B scope what to do

More power to ya if you can learn how to use a scope to troublshoot electronics without having gone to school for electronics. The school I went to not only had 2 years of electronics theory but also lab classes where we learned how to use scopes, multimeters, capacitor checkers, function generators, frequency counters, spectrum analyzers, and much much more.

You can definitely learn how to use it, hopefully without any damage to the scope or your project. Really, I only use a scope when I know what type of signal I should be looking at on a certain point in a circuit(especially without a schematic). A good example would be this switching power supply I just worked on had a pulse width modulator chip. Without knowing what type of signal to look for, I would not know if this chip was working or not. If this is your new found hobby then you just entered a fun world of science! Have fun with it, dont get discouraged.

[sam67]

Re: Help with techtronix 465B scope what to do

Dgtech,

Thanks for the kind words ..yes i have had no electronics training and have learned from some ebooks that i bought ..jestine yong stuff..so using dvm and esr meter and blue ring tester i am getting there lol i know how these work and if i am not sure i just ask on here or email jestine..Also have lcd tv by john preher which is very good..

The ebooks show what wave forms to expect but does not go into all the scope settings ...If i can learn the correct way to set up the scope then i can work from the ebooks as it shows you the right places to put the scope probe and what to expect so at least i have a start ..

I am really enjoying this fine journey as i like to learn but nearly gave up with the scope untill i got it working thanks to stj ..I have a long way to go but will not give up no matter how hard it gets..

Cheers

sam

[stj]

Re: Help with techtronix 465B scope what to do

what's the voltage rating on the probe?

[PlainBill]

Re: Help with techtronix 465B scope what to do

Thanks Stj,

I have now managed to get the trace looking at the link you provided ,Here is a pic of the scope ...The trace looks better than in the pic due to the light...But if anyone can help me to set this up better if i have missed some thing then it would be great.

Now what would be the recommended settings to look at some of the components in my faulty psu that has intermittent problem..Can i use these settings in the pic to look at the main filter cap for ripple or check on the pwm ic that i have the data sheet ? just so i can get an idea how the scope is doing.

Any help appreciated as i am trying not to give up even with my limited knowledge .

ps i have changed the setting to DC coupling on the left side which is in AC on the pic..i only noticed once i looked at the pic lol

A word of warning!!! All points in a SMPS power supply between the bridge rectifier and the transformer are HOT with respect to circuit ground. Specifically, neither lead of the large capacitor can be used as the probe ground without damaging the power supply, the probe ground lead, and possibly the scope and yourself.

To observe the waveforms at those points you will need an isolation transformer.

PlainBill

[Radio Fox]

Re: Help with techtronix 465B scope what to do

Sam67...have you tried connecting the probe to the "calibrator" bar? This will give you a waveform to play around with, so you get a feel for the time/div & volts/div controls.

It will also let you trim your probe on the X10 setting for the best waveform.

[Krankshaft]

Re: Help with techtronix 465B scope what to do

Put the probe on the calibrator bar.

You want to adjust the calibrating screw with a non metallic tool so the edge of the square wave is straight.

[sam67]

Re: Help with techtronix 465B scope what to do

what's the voltage rating on the probe?

Hi stj, the probe says x10 100mhz 13pf 10M ohm 2meter TEK.

(Quote)
A word of warning!!! All points in a SMPS power supply between the bridge rectifier and the transformer are HOT with respect to circuit ground. Specifically, neither lead of the large capacitor can be used as the probe ground without damaging the power supply, the probe ground lead, and possibly the scope and yourself.

To observe the waveforms at those points you will need an isolation transformer.

PlainBill

Hi plainBill, It mentions what you said about the isolation transformer in the ebooks that i have so will take your advice about that before i probe those areas thanks .

To Krankshaft and RadioFox , i have not tried this yet ...do i need to attach the ground clip anywhere when i come to put the probe on the calibrator bar ?

Sorry for late replies as this week has been a little hectic so not had much time.

Thanks again to everyone on trying to get me to sort this out correctly.

Much appreciated

sam.

[sam67]

Re: Help with techtronix 465B scope what to do

Forgot to add can anyone recommend me an isolation transformer that will work well with my scope ..Any links would be appreciated as i am not sure what i need .Don't want to be probing anywhere yet till i get one and can work the unit correctly .

Thanks

[Radio Fox]

Re: Help with techtronix 465B scope what to do

...To Krankshaft and RadioFox , i have not tried this yet ...do i need to attach the ground clip anywhere when i come to put the probe on the calibrator bar ?...

Try it without connecting the ground lead first. If the waveform looks a bit noisy, poke the ground lead into the GND socket on the front of the scope.

[sam67]

Re: Help with techtronix 465B scope what to do

What type of waveforms can i get when attaching the probe to the calibrated bar ? or do i need to hook it up to anything else.. How can i get a full square waveform..

cheers

[Radio Fox]

Re: Help with techtronix 465B scope what to do

What type of waveforms can i get when attaching the probe to the calibrated bar ? or do i need to hook it up to anything else.. How can i get a full square waveform..

cheers

Page 2-10 of the manual shows you how to set the scope controls for basic measurements. Set the CH 1 volts/div knob to 0.1V. Where it says "connect a signal to the CH 1 input connector", plug your probe into CH 1 & clip the hook of the probe onto the calibrator bar.

To start, make sure all the red var knobs are turned fully clockwise to extinguish the "uncal" lights.

You should see a tightly spaced square wave. Turn the time/div control clockwise to widen it out. Turn the CH 1 volts/div to alter the amplitude. Play with the red "var" knobs to see what they do (but remember to always have them fully clockwise if you want to take accurate readings).

As Krankshaft says, there is normally a trimmer on the body of the probe that you can adjust for the best waveform. Too far one way & the edge of the squarewave will be rounded. Too far the other way, & the edge of the squarewave will overshoot, producing a spike. Adjust it to give a near a square edge as possible.

[Radio Fox]

Re: Help with techtronix 465B scope what to do

btw...there's no need to wait 20 minutes for the scope to warm up, as stated in the manual. That's only if you want to make accurate measurements that are within the spec of the scope.

[sam67]

Re: Help with techtronix 465B scope what to do

Hi Radio fox,

Thanks for the info..i can get sort of a squarish waveform but the the vertical side of the square is faintish but the top and bottom are very clear if you can understand what i mean..I cannot see a trimmer that you mention ? the probe i have does have a kind of button but that just says GND REF and when pressed just goes to a single line..

Also when i eventually try some tests i have to make sure none of the VAR knobs are turned on meaning the uncal lights are all extinguished right ? The only dial i don't know what setting should be is the delay time position ,it reminds me of a dial that you see on a safe lol.

Thanks

[Radio Fox]

Re: Help with techtronix 465B scope what to do

Hi Radio fox,

Thanks for the info..i can get sort of a squarish waveform but the the vertical side of the square is faintish but the top and bottom are very clear if you can understand what i mean..I cannot see a trimmer that you mention ? the probe i have does have a kind of button but that just says GND REF and when pressed just goes to a single line..

Also when i eventually try some tests i have to make sure none of the VAR knobs are turned on meaning the uncal lights are all extinguished right ? The only dial i don't know what setting should be is the delay time position ,it reminds me of a dial that you see on a safe lol.

Thanks

I mistakenly thought that all X10 probes had a compensation trimmer. Obviously not.

The GND REF button on the probe is handy for checking the reference position of the trace when taking voltage (Y axis) measurements.

If you want to use the scope to take accurate measurements, then the red VAR knobs must be turned to extinguish the uncal lights. Normally it is fully CW. You will probably notice a slight "click" when it's in the right position.

Dont bother with the Delay knob yet. That comes under the heading of "advanced tutorials". LOL.

btw...did you try connecting the earth clip to the front panel earth socket?
Also, I am wondering if the astig & focus controls might need adjusting to help in giving a clearer display of the waveform.

[stj]

Re: Help with techtronix 465B scope what to do

it could have a trimmer on the bnc plug.

[sam67]

Re: Help with techtronix 465B scope what to do

@ Radio Fox,

Yes i have tried ground clip but does not make any difference ,should i be able to get a full square waveform with it just connected to calibrated bar ? like i say it's just the vertical edges of the square waveform that are very faint ..It does have the astig and trace location on the front which looks like i'd have to turn them with a screwdriver but not sure whether to or not .

@ stj i don't see a trimmer on the probe at all ..

Would have liked to have tried this scope out but it seems i have to run it through an isolation transformer before testing on live circuits but cannot find one and don't really know what would be right to work with my scope..

I will be away from tomorrow till about tues so don't think i am not responding to any posts.

Like i have said before it's much appreciated guys for the help.

sam67

[Radio Fox]

Re: Help with techtronix 465B scope what to do

...should i be able to get a full square waveform with it just connected to calibrated bar ? like i say it's just the vertical edges of the square waveform that are very faint ..It does have the astig and trace location on the front which looks like i'd have to turn them with a screwdriver but not sure whether to or not...

I'm not sure what you mean by a full square waveform. If you alter the volts/div & time/div controls then you should be able to make it look square (i.e the same number of vertical & horizontal divisions).

Setting your time/div knob to 0.5mS will give you 1 square wave cycle every 2 divisions. So you should see a high (top of waveform) for 1 division, then a low (bottom of waveform) for 1 division across the screen.

From your photo, the trace rotation looks OK, so don't touch that.

From the description of your waveform, I am wondering if the astig & focus controls are set correctly. The usual way to set the astig, is to set the time/div to the X-Y position (fully anticlockwise) to give a dot on the screen. Use the horizontal "position" knob, if necessary to move it nearer the centre of the screen. Do not connect anything to the CH 1 input. The astig control is adjusted to give a perfectly rounded dot. Adjusting the astig too far one way will produce a wide oval, too far the other way will give a tall oval. If the dot is too small to see the astig adjustment clearly, then you can adjust the focus control to unfocus the dot to make it a bit bigger.

After adjusting the astig, readjust the focus (if necessary) to give a sharp dot.

Can you post another photo showing the waveform you are getting.