moh.vze.com Posted May 9, 2009 Report Share Posted May 9, 2009 (edited) My 3 day banned is finally up! I'm never replying in those Tunez thread again! Anyhow, back on topic. After reading the thread on the velleman oscope on here, I decided to go buy one. I bought my unit from Kitusa.com. I am having issues calibrating my probe (I've tried two different probes and I've had the same problem). My problem is that when I calibrate at .1ms/div at 1V/div, it would seem like I have a flat top but when I zoom in to .5V/div, it shows the curve #1 in the below image. When I try to flaten that out at my .5V/div, it would start to look like image #2 (the green curve below) when I put it back at 1V/div What is going on? Please help. Again, I bought this unit from Kitusa.com if this unit is really defective, I'm going have to return it and try and get a full refund ASAP. Are they even authorized to sell this unit? Do I have any warranty? Note this is just a random image I've googled that will help me describe my problems. I keep getting a weird bump on my square waves that looks something like this: I am currently trying to get tech support from the velleman company's forum but they keep refusing to help me until I take a picture of my oscope. http://forum.velleman.be/viewtopic.php?f=9&t=3053 I've been waiting for my friend to reply in letting me borrow his digital camera so I can take a picture. I don't see what's the point because I've describe in full detail already. Right now, I am pretty pissed off at this scope and the company. Please help me out! Edited May 9, 2009 by moh.vze.com DC Audio - Singer Alternators - Knukonceptz - XS Power - Hybrid Audio - Rockford Fosgate - Second Skin Audio - SMD - Sundown Audio - Elemental Designs Link to comment Share on other sites More sharing options...
Loudcav Posted May 9, 2009 Report Share Posted May 9, 2009 Ive got one of those I didnt bother calibrating it tho it shows clipping in the center of the wave on mine Link to comment Share on other sites More sharing options...
moh.vze.com Posted May 9, 2009 Author Report Share Posted May 9, 2009 Ive got one of those I didnt bother calibrating it tho it shows clipping in the center of the wave on mine I'm trying to figure out if all velleman scopes are like this. I was going to use this scope later for some of my electronics labs if I ever work on them at home and I just want my scope to be accurate. DC Audio - Singer Alternators - Knukonceptz - XS Power - Hybrid Audio - Rockford Fosgate - Second Skin Audio - SMD - Sundown Audio - Elemental Designs Link to comment Share on other sites More sharing options...
Boon Posted May 9, 2009 Report Share Posted May 9, 2009 1. It's not exactly a pricey scope, what did you expect? 2. What are you using for a calibration source? Does that scope even have a calibration lug on it? 10.x volts fo' life! Link to comment Share on other sites More sharing options...
Stephen Posted May 9, 2009 Report Share Posted May 9, 2009 mine works fine you can cook bacon shirtless if you're not a pussy...lol not hatin, but am i wrong here it looks as if the amp is not grounded its hooked directly to the battery. it that the way it should be. DC POWER Link to comment Share on other sites More sharing options...
Shyne151 Posted May 9, 2009 Report Share Posted May 9, 2009 Ive got one of those I didnt bother calibrating it tho it shows clipping in the center of the wave on mine umm they have to be calibrated to be even remotely effective. -Installer for Duke's Car Stereo 2000 Pontiac Grand Prix - Ported Eaton M90 S/C, 3.5" pulley, XS Power Headers, 1.9 Rockers, FWI, Poly Motor Mounts, Custom Tune. RF T1000-1bdCP and T400-4 Boston Acoustics SPG 555 Kenwood eXcelon 995 RF Punch 6.5" components and MB Quart Premium 6x9"s Powermaster Alternator, YellowTop D34, Vmax CT1000 Link to comment Share on other sites More sharing options...
may03LT Posted May 9, 2009 Report Share Posted May 9, 2009 Does that scope even have a calibration lug on it? on mine it's behind the battery cover Link to comment Share on other sites More sharing options...
moh.vze.com Posted May 9, 2009 Author Report Share Posted May 9, 2009 on mine it's behind the battery cover So is my unit defected? This is fucking pissing me off. I'm never buying scopes online again. That fucking kitusa.com won't even reply my emails. I keep getting error messages when I try to send them email. DC Audio - Singer Alternators - Knukonceptz - XS Power - Hybrid Audio - Rockford Fosgate - Second Skin Audio - SMD - Sundown Audio - Elemental Designs Link to comment Share on other sites More sharing options...
cliffyk Posted May 10, 2009 Report Share Posted May 10, 2009 So is my unit defected? This is fucking pissing me off. I'm never buying scopes online again.That fucking kitusa.com won't even reply my emails. I keep getting error messages when I try to send them email. I replied to your post in the Velleman forum, however I will report my reply here for the benefit of others. For reference, here is one of the photos you posted there: ========================================= You are getting a perfect calibration, it's the top of the waveform that matters. not the sides... The effect you are seeing is typical of digital all scopes, and is only more pronounced on the HPS10SE because of its 128 pixel wide display and 10Mhz sampling rate. While a perfect square/rectangular wave would have 0.0s rise and fall times, the reality is that there's no such thing as a perfect square wave, they all take time to change from high to low voltage and vice-versa. What you are seeing is that the calibration signal fell from its maximum level to its minimum level over a period of two samples made by the scope. One was made while the signal was high, the other while it was low, since the two samples represent different points in time the display of the falling signal is "stepped". This is the same effect as the horizontal steps seen in the top and bottom of the "peaked" and "rolled" waveforms, the difference being that the horizontal steps represent the scope's vertical (voltage) resolution while the vertical steps represent the unit's horizontal (time) resolution. Here is a screen shot from my $3200 Lecroy WJ-322 scope showing the same effect, deliberately exaggerated through selection of a slow rise/fall time wave. This was recorded at a 500MHz sample rate. In the top trace the red arrows show the steps created by changes in level that fell between samples. The bottom trace is a 10x zoom of the selected portion of the top trace, showing the "real" shape of the falling level. Note however that there are still steps, just smaller ones. Short story, there's nothing wrong with your 'scope... -cliff knight- My Mustang Link to comment Share on other sites More sharing options...
Dr. Johnson Posted May 10, 2009 Report Share Posted May 10, 2009 Nice... Welcome to SMD Cliffyk Link to comment Share on other sites More sharing options...
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