Analog oscilloscope can be important in several phases of the install, eg. to verify InputTrigger
- even though thousands of installs have been completed with DVM only (without oscilloscope), in some cases scope is just essential to see what is going on to diagnose and proceed (without a combinatorial explosion of guess-and-try).
Since about 2010, some scopes are very affordable (toolbox real-estate, weight, cost, ...) and investment is often returned on first or second install.
- DSO138-style pocket scopes, and USB scopes come to mind.
- wether you are a professional installer, or going to become one, or a novice, doing the first install, make sure to always have oscilloscope
- As of 2018, DVM + oscilloscope (yes, both!) is considered an essential tool, (helps you a lot, and helps everyone who tries to help the installer) required for support (even if DVM is still used slightly more often).
- DSO138 pocket scope can be ordered as
- DIY "KIT" solder yourself (avoid, unless for fun; if you also have another, factory assembled device)
- SMD-soldered (the throughole is still solder yourself: avoid). Examine the ad: if there are pictures of both assembled device, and some standalone resistors, assume that it is solder yourself version (avoid)
- soldered : good, choose this only ~3 EUR more than the smd-soldered or DIY kit.
Sad Scope Story
An installer from EU agreed to make some installs in USA, during a trip (appr 2 weeks).
- he had his scope among the stuff to be packed, but since the USA customer told him they have oscilloscope on site, the scope did not make into the luggage finally
- often redundant parts (like a scope, if available anyway at the destination) in luggages are replaced with other (personal or technical) goods to utilize the weight limits reasonably
- The installer made 5 successful installs.
- However, during the 6th install (the customer is not the same as the other 5), he ran into VR problems
- tech support informed him from day 1 that scopeshots are required, otherwise it's a waste of everyone's time.
- the installer communicated that he suspects some wheel related artifact, which, however can NOT be verified without the scope: the customer was repeatedly informed about the scope requirement (which he told was available in the first place)
- however no scope became available during the the installer's visit time frame.
- This obviously caused an immense amount of work for everyone, and no success for that +1 install
- after the installer flew back to EU, the customer still didn't have scope for more than a week.
- although it was made clear that diag by scoping is the next step to proceed, the customer decided to replace the wheel (7..14 hours of garage work usually). That did not help, and the customer decided to demand the full device + install fee (but keep the devices, ECU + harness)
- and perhaps also insist on some +$$ compensation for his decision to do the engine mech works, although almost certainly that is not reasonable. There is no liability for consequential damage, but that is consequence of his decision, not the orig )
- although it was made clear that diag by scoping is the next step to proceed, the customer decided to replace the wheel (7..14 hours of garage work usually). That did not help, and the customer decided to demand the full device + install fee (but keep the devices, ECU + harness)
This is how (the lack of) a 100 USD scope can cause an 1700 USD damage (waste a lot a time).
The installer could insist on compensation if the customer informed him "scope is available" which was actually not. However, in practice it is unlikely to worth it, and the customer can cause more damage (eg. by advertising without telling how his actions made the install impossible and causing costs for everyone).
We recommended the installer to not insist on the return of harness and ECU (which would be the normal procedure), we grant him an ECU and wires, connectors for the harness (as a "voluntary insurance" to help resolve, and avoid unnecessary further damage, eg. shipping costs, brand damage, ...).
Hoping this short story helps installers and customers.
Soundcard is sometimes useful to capture stereo (or even mono) audio, but not a real substitute.
No need for 20..100MHz scopes... 1Msps is almost always suitable, or even 500ksps.
There are some cheap DSO138-style pocket scopes, and USB scopes also.
- a divby10 probe or a voltage divider protection never hurts
- the DSO138 is better, less work, easier to use than a 3.5mm jack +notebook soundcard input
- soundcard input often creates a ground loop (often the USB-RS232 is also connected to same ECU). Might work well in practice though
- soundcard input is often mono, not stereo, be warned