Oscilloscope set up

[bembo449]

Anyone actually know how to set one up ?? Ive got a small hand held unit and ive searched youtube for answers but know one says how you physically set up for what your testing ? Please see pic
I want to test my engine wiring harness for signal / voltage so what do i use ??
Thanks

 

[Nigel Hewitt]

Anyone actually know how to set one up ?? Ive got a small hand held unit and ive searched youtube for answers but know one says how you physically set up for what your testing ? Please see pic
I want to test my engine wiring harness for signal / voltage so what do i use ??
Thanks

OMG an oscilloscope controlled by 5 buttons? Mine has 28 buttons and 8 rotary encoders and a lot of stuff is hived off onto menus and that's just a simple one.
Traditionally an oscilloscope shows a moving dot that travels across the screen that rises and falls to indicate the changing voltage on the probe.
Digital ones like that show a line where the dot passed rather than a dot.
The important settings are how fast the 'dot' moves across the screen and how far the 'dot' moves up and down for the input
measured in sec/cm or cm/sec (or mSec,uSec) and V/cm (or mV)
Hopefully you have some instructions.

How you then interpret the results depends on what signal lines you are looking at.
I am not sure it is the right tool for any car job although I used one to diagnose a problem with the ECU of the air suspension on my old P38 Range Rover after the main agent failed three times.

 

[bembo449]

Helpful and sarcastic? Ive never needed or used one before ! And although you gave a thorough explanation of , you still didnt tell me wether i need to use the crocodile clips or the probe or ???

 

[Nigel Hewitt]

The crocs are a direct connection, the black is ground and the red is signal.
The probe is usually designed to be a very 'light touch' on the circuit being measured so it doesn't change what
it tries to measure but as a result only gives a tenth of the input. You just select a range or so down.
HOWEVER the probe has an adjusting screw that needs to be set or everything is horribly distorted.
Hopefully the 'scope came with instructions for that.

I can ramble about 'scopes all day. They are my favourite instrument baring a full Vector Analyser. I just find that
one just a bit scary because all the things I want to adjust must be 'on-screen' so I can't describe them.

 

[EmilysDad]

....

I am not sure it is the right tool for any car job although I used one to diagnose a problem with the ECU of the air suspension on my old P38 Range Rover after the main agent failed three times.

Diagnose Dan often uses a scope

 

[supernoodle]

Diagnose Dan is the master, but Mechanical Mindset does more using a scope on a vehicle

 

[supernoodle]

Following on from comment about probes above, assuming that probe supplied is marked as X10, that is there to allow you to look at signals that would otherwise exceed the max input channel voltage. You don't need that for the vehicle. What you're looking at will be up to battery voltage. Yes, injectors, coils etc are higher but you wouldn't go sticking your probes in there, you'd use a current clamp (mechanical Mindset has vids here too) for these. But to honest at this point you'd probably be wanting more than one channel so would wanting something like the picoscope, so starts getting more expensive.

If you're you're just wanting to look at simple sensorsnlike abs, MAF, cam, crank signals etc this will be fine. If you want to look at h bridge circuits like you find on some motor circuits (EGR, throttle, turbo etc) really need 2 channels too.

Stick with the bnc to crocs for now, though you'll probably want to chop the crocs off later and put some 4mm bananas on the end that you can use with some back pinning probes.

Pardon our interruption...

www.ebay.co.uk

 

[bembo449]

the probe is indeed a 10x probe . i really just need to be shown what to use on which system and the i think i can firgure it out

 

[supernoodle]

Just clip the black to chassis ground, unwind a paper clip, connect the red croc clip and start poking around. It looks like it has autoranging button, so that will set the timescale and range for you.
I'm guessing this is for the Maserati, so no idea what signals are used there. Chances are the MAF is a variable frequency, so try and find that signal . Try the EGR and throttle, they will I guess be a either be simple PWM, or H bridge, which is effectively two PWM signals.
Just keep it away from the injectors.

That's the point of a scope to poke around and see what's going.

 

[bembo449]

ok ive got a needle probe set aswell as the scope kit , it is for my maserati , its the final stage of hopefully getting it running properly , appreciate the advice

 

[bembo449]

Update , so ive experimented but auto range doesn't appear to help !? Any advice on manual set up please ?