4423 using 3rd and 4th channels.

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4423 using 3rd and 4th channels.

Postby hexibot43 » Fri Nov 22, 2013 4:38 pm

I've been really giving my scope a lot of work lately. I've been trying hard to not get to frustrated. It seems that it is shutting off frequently while in use. I have to unplug it and then plug it back in to get it working again. I noticed yesterday that the more channels I am trying to use the faster it happens. I am now no longer attempting to use AC power or any external power for my laptop. ( Line noise creeping into my signal path ).

How much current draw change is there as I add each channel into the mix? Could a weak USB power source be the cause of my issues? If so can I use a powered hub to help inject some more power into the circuit? I've got a powered USB hub around here somewhere. I guess I'll try plugging it in and see if the scope still responds through the hub. I notice the red lamp on the scope is out when it stops working. I've been playing with RaspberryPI and see how sensitive it is to power on the USB port. Suddenly an idea pops in my head. Am I dealing with the same problem with my scope? I will give the Hub a shot and post my findings. Every time I start working with AC pulse generators and want to use multiple channels to read boh the negative and positive, combine them, and display them using a Math channel the scope really goes has issues.

It's that time of year here when all the electrical problems start showing up in cars.
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Re: 4423 using 3rd and 4th channels.

Postby Autonerdz » Fri Nov 22, 2013 5:54 pm

hexibot43 wrote:Every time I start working with AC pulse generators and want to use multiple channels to read boh the negative and positive, combine them, and display them using a Math channel the scope really goes has issues.


Just picking up on this statement and wondering if you are creating a ground loop with your hook up. Remember that the channel grounds are common. Any and all channel ground leads should be on battery negative but only one channel need be grounded. You should not place your channel grounds on any sensors. You 'can' do this if only using one channel but it is not recommended and not necessary since math channels were born.

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Re: 4423 using 3rd and 4th channels.

Postby hexibot43 » Fri Nov 22, 2013 7:07 pm

No ground loops. All grounds tied together and connected at the battery. I will try connecting only one. I've also tried not hooking any of them up when using all channels as differential.

What do you think of the USB hub idea? Before I go adding that into the mix.
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Re: 4423 using 3rd and 4th channels.

Postby Autonerdz » Fri Nov 22, 2013 7:36 pm

Just making sure that was not the issue.

We recommend always having one channel grounded to B- even if you are not using that channel when using current probe, etc (which are not grounded) to provide a scope ground.

There are exceptions but there has to be a good reason.

Would not hurt to try the hub but also make sure you have sufficient PC resources and the PC is not falling down.

What version of PicoScope are you using?

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Re: 4423 using 3rd and 4th channels.

Postby hexibot43 » Fri Nov 22, 2013 8:12 pm

Currently running Picoscope 6.7.40.3 It was updated in the middle of all my fun yesterday. I was hoping that might help but did not.

I'm running an IBM t60 with Core Duo T2400 running 1.83 two times. 3 Gigs of memory. 129 gigs free hard-drive space. Going back to my T43 did not help.

I am following your grounding recommendations.


I have had weird aberrations in signals when I attempt to use the 3rd and 4th channels since I've gotten the scope. But the shutting down has started to happen much more often. I would love to get to the heart of the issue. I really like this scope. When I've gone back to using my older scopes I suddenly realize all I'm giving up. The trigger controls alone are worth the headaches I've had.
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Re: 4423 using 3rd and 4th channels.

Postby Steve Smith » Wed May 07, 2014 2:46 pm

Hello Hexibot and thank you for all the information above. I have been reading with intrigue the issues you have experienced with the scope under the measurement conditions you describe. Of course I would like to know if the issue has been resolved and how you managed to cure the concern.
I have a few questions of my own and hope you can feedback if possible?

Was the issue only ever apparent when measuring AC pulse generators?

Was the issue only evident once the 3rd and 4th (C+D) channels became active or would 1st and 2nd (A+B) channel alone generate the same symptom?

Can you confirm if the scope is connected using the PicoScope dedicated blue USB lead?

Have you been able to test a donor PC/laptop with your scope under the same test conditions?

My line of thinking here is does your laptop have a “power saving function” affecting the USB supply?

Did you try the hub and what was the outcome?

The power consumption of the 4423 falls well within the capability of USB ports 1.1 and above although USB 2.0 is recommended.

Sorry for all the questions as this will help me with my support role here at Pico and I understand if you take one look and think “I am not answering all that”

Once again, thank you for the post and take care……Steve
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Re: 4423 using 3rd and 4th channels.

Postby hexibot43 » Sat Aug 16, 2014 3:55 pm

I know it has been a while since I started this post. I just hadn't ever figured out what was going on until now. If anything I had gotten even more frustrated while using the scope. I decided to try another computer. My boss had bought me, a new Dell with USB 3.0 to run some BMW software I had. I installed the Pico software to give it a go. I can barely get the computer to recognize the scope. When I started the software it would just freak out. flashing connect device over and over. Best thing that ever happened. I'm now thinking there is something wrong with the scope. But first I decided to try a different cable and presto all my problems disappeared!!! That was the third cable I had tried. Third time was the charm. Obviously there was something wrong with the cable. :shock: I'm guessing I must be a little rough on these cables.

Now that I've gone through this I really wish I had had some way to test communications with the scope. Would there be a trace of the faults I was getting? Some Error log or something. I still have the cable to try things out.

Is there some way to send packets to and from the scope, and get error reports?

So be careful of USB cables.

My scope is working rock solid now. And on Multiple computers. I honestly think I've had cable problems from day one. I remember switching to a different cable early on because the cable I had got with it was acting up. The second cable was working, but still not ever really right. Now that I have a good cable and know how well it can run I can honestly say that.

Another thing I just realized...I don't think I ever had the dedicated blue cable. I bought things piece meal because I didn't have $2000 to give it a try. I bought the bare 4423, and then worked my way up to having the whole kit. I bought everything through my local Matco tool dealer. Something I'm regretting now.
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Re: 4423 using 3rd and 4th channels.

Postby Martyn » Tue Aug 19, 2014 7:06 am

The blue cable is supplied with the scopes even when not part of a kit. It is specially made for us to our specification, and has better quality cores to ensure that the devices receive the power they require. If you haven't got one then just drop an email to support@picotech.com and we can get one out to you.
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Re: 4423 using 3rd and 4th channels.

Postby hexibot43 » Fri Aug 22, 2014 2:42 pm

Got a message from support and will be ordering a couple cables at the beginning of the new month.

I am finally getting to really enjoy this scope. I can see now that I never had a good cable because it never worked like it is working now. All four channels working. I had been fighting strange things going on when I tried to use the 3rd and 4th channels. Now they just work perfectly. :D . I haven't had the scope shut off once. I had been having that trouble on and off. Ran it through the night hooked up to an Arduino project I was working on with great success.
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Re: 4423 using 3rd and 4th channels.

Postby rburgy » Wed Jul 08, 2015 10:47 am

Just my 2 cents. I also had this problem. The scope would keep shutting down and alot of time the pc wouldn't recognize my scope. My USB. Cable was bad. I bought the best one i could find and have not had a problem since. That was about a year ago.
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