Oscilloscope...

[Citation]

I have the 54622A and it is an excellent 'scope for the money. Despite its size, it is 'portable' enough that I have used it for automotive purposes on a couple of occasions. I primarily use mine for building/repairing tube amplifiers, which it is more than capable.

I found one for my brother for the exact same reason! He got into making tube electronics even though he has no EE background. I surprised him with a scope and at first he wasn't sure what to do with it. Once he used it for a bit it became one of those indispensable tools.

 

[richfinn]

I found one for my brother for the exact same reason! He got into making tube electronics even though he has no EE background. I surprised him with a scope and at first he wasn't sure what to do with it. Once he used it for a bit it became one of those indispensable tools.

It's one of those tools, once you have used one to fix a fault, you can't go back to what you used to know

You basically own a "Time Machine" that can look into the recent past

 

[theoldwizard1]

You basically own a "Time Machine" that can look into the recent past

In the early/middle 80s, digital storage 'scope did not exists. Tektronix did make a version of their 7000 "mainframe" 'scope that had "persistence". Add in the time base and a couple of amplifiers and you were talking multiple tens of thousands of dollars !

 

[richfinn]

In the early/middle 80s, digital storage 'scope did not exists. Tektronix did make a version of their 7000 "mainframe" 'scope that had "persistence". Add in the time base and a couple of amplifiers and you were talking multiple tens of thousands of dollars !

I started off with CRT Oscilloscopes in the 80s, it's amazing how cheap DSO's actually are nowadays!!

 

[SuzukiGS750EZ]

I'm going to start on my amplifier and go from there. I wish I thought about it when the knock sensor circuit in the Silverado was on the outs...

My dad's truck just threw a p0420...

 

[2ndGearRubber]

I'm going to start on my amplifier and go from there. I wish I thought about it when the knock sensor circuit in the Silverado was on the outs...

My dad's truck just threw a p0420...

Knock sensors are fun to diagnose with a scope.

And you can actually diagnose them, rather than just ohm the harness and chuck a part like the OEM trouble trees basically tell you to do. It's usually pretty cut and dry once you see the pattern - a small dead/weak spot in output frequency within the rpm range.

 

[theoldwizard1]

I started off with CRT Oscilloscopes in the 80s, it's amazing how cheap DSO's actually are nowadays!!

In the late 70s with still had a Tektronix 555 sitting in the corner or the lab. I tried to fire it up one day. Fellow engineer told me, "Don't bother, it takes at least 30 minutes for it to temperature stabilize before you can do anything with it."

The best use for it (if you were crazy enough) was to use it as a coffee warmer. That thing ran HOT (it was all tube, IIRC).

 

[theoldwizard1]

Knock sensors are fun to diagnose with a scope.

in the early/mid 80s, the guys sitting in the next row had to do a "dog and pony show" for the big bosses to show how know detection actually worked. You have to remember those guys were all "cast iron mongers" and knew nothing about electronics and even less about software. They has signal generators and an intake manifold with a knock sensor, a hammer and 3 'scope to show how the signal was captured, separated from the other engine "noise", processed and the spark advance was retarded.

 

[SuzukiGS750EZ]

Knock sensors are fun to diagnose with a scope.



And you can actually diagnose them, rather than just ohm the harness and chuck a part like the OEM trouble trees basically tell you to do. It's usually pretty cut and dry once you see the pattern - a small dead/weak spot in output frequency within the rpm range.

Yup... I did the old resistance test and threw in two sensors and a harness. I've seen them come through the shop before and done a bunch so I just did em. Would have can nice go see in the scope though

 

[joel63]

This thread is one of the most outstanding threads I have ever read on GJ.
All the posters have have done super job on helping Suzuki work through his deal with great advice and recommendations.
I have read it from beginning to end 3 times and learned a lot from it.
I have used a scope as a DIYer for the past 10 years and I'm constantly working to upgrade my skills
Way to go guys! Beer for all!!!

 

[SuzukiGS750EZ]

This thread is one of the most outstanding threads I have ever read on GJ.
All the posters have have done super job on helping Suzuki work through his deal with great advice and recommendations.
I have read it from beginning to end 3 times and learned a lot from it.
I have used a scope as a DIYer for the past 10 years and I'm constantly working to upgrade my skills
Way to go guys! Beer for all!!!

I agree. I at least have the tool in hand! It's a bit cold for me to comfortably mess with it on the car but if I can do anything with common household stuff, feel free to let me know! I have the scanner danner book that I've been going through based on recommendation from this thread.

 

[theoldwizard1]

I have used a scope as a DIYer for the past 10 years and I'm constantly working to upgrade my skills

Practice make perfect !

Like a scan tool, neither is a substitute for good basic understanding of how an engine works or how electricity works (plus a little bit of electronics, such as ground side switching).

 

[crerus75]

If you consider a bench scope, the Agilent HP 54621A (and family) scopes are older but excellent choices. They are under $200 on ebay all day (you may have to buy new probes, $20 for cheap ones). The reason why I like these scopes is they are very responsive. Many cheap scopes have poor refresh rates (even if they have good frequency response rates). These are just very fast to respond to any control input. They do a good job capturing glitches, and have a very good deep memory function. I suspect they are cheap because they are green CRT vs LCD. Of course that has another advantage, they have 1000 horizontal points (vs many of the LCDs which are 480x800). Another drawback is they are deeper (about 1' vs perhaps 4" for a modern lunchbox scope). Back in the day these were HP's not cheap, mainstream bench scope.
https://www.keysight.com/en/pd-1000000808:epsg:pro-pn-54621A/portable-dso?cc=US&lc=eng

Do you happen to know what the max input voltage is on one of these? I thought I saw a post recently on one of the electronics forums about how they were limited to 20Vpp max (don't shoot me if I'm wrong, my memory is like a sieve these days). If so, you'd need at least a 10:1 probe when looking at anything with an inductor, like a fuel injector.

 

[crerus75]

An incandescent test light is an incredibly valuable tool. It is typical not important to know voltage (anything below 10V will be dim) but knowing that there is adequate power at the test point is HUGE ! That is why mechanics might use a standard test light (which draws about 250mA or 1/4 A) for some tests, but will make their own "high current" (1A - 5A) test light.

I have several automotive bulbs with test leads soldered to them. My test light draws 250 mA after it warms up, but I have some 9006 headlight bulbs that draw just under 4A apiece at 13.5V (IE engine running). Great for testing something like an O2 heater circuit. Dirt cheap, easy to replace, and you can practically see the damn thing from outer space. Eric O from South Main Auto calls them a "Scope On a Rope".

 

[Citation]

Do you happen to know what the max input voltage is on one of these? I thought I saw a post recently on one of the electronics forums about how they were limited to 20Vpp max (don't shoot me if I'm wrong, my memory is like a sieve these days). If so, you'd need at least a 10:1 probe when looking at anything with an inductor, like a fuel injector.

Jury looking at a picture on line or says 300V CAT1. I don't know if that assumed a 10x probe.

Edit: verified, 300 peak to peak on mine

 

[crerus75]

Jury looking at a picture on line or says 300V CAT1. I don't know if that assumed a 10x probe.

Edit: verified, 300 peak to peak on mine

Thanks. Dunno where I got the 20V from. Must've been some other piece of test equipment I was reading about.