VC2003 Function Generator <shudder> - Page 1
Forum section: electronics / testgear

author: K6EEP
author_rank: Contributor
timestamp: January 23, 2015, 03:22:31 pm
content: I bought this thing on EBay before I knew any better. I was inspired by the EEVblog to hook it to my scope (Tektronix TDS-2014B) and have a look at a square wave on it. I had never played with this thing much after the front panel fell off. I glued the front panel back on since then. But I thought I should at least try it.Here is a picture of the unit.Here is a 2Mhz square wave. The scope couldn't sync to it very well for some odd reason. LOLWun Hung Lo Factory strikes again.On a side note. Even though the scope has the screenshot capability I used my cell phone.

author: janoc
author_rank: Super Contributor
timestamp: January 23, 2015, 04:06:17 pm
content: I have seen these around in various variants, mostly ones without the keypad. I would check the max frequency, I believe most are up 3MHz max, with many 1MHz models around. And when you push the limits, it goes all gaga.That is not an excuse for how atrocious your unit is, though - it may even be defective. This is a review of the VC2002 version - still crap, but nowhere as bad as yours:

author: mij59
author_rank: Frequent Contributor
timestamp: January 23, 2015, 04:22:02 pm
content: Hi,Time base 5 msec and a 2 Mhz signal results in Time Domain Aliasing, check the manual of the scope, page 20.

author: K6EEP
author_rank: Contributor
timestamp: January 23, 2015, 05:38:05 pm
content: Argh! Thank you.

author: K6EEP
author_rank: Contributor
timestamp: January 23, 2015, 06:10:19 pm
content: Updated image. Set scope to Peak Detect, and 100nS.And I have a manual for my scope now too. LOLIt's cleaned it up a bit. This unit can go to 3Mhz.

author: mij59
author_rank: Frequent Contributor
timestamp: January 23, 2015, 06:29:56 pm
content: Hi,Your scope doesn't have a 50 Ohm input setting, in order to get rid of the ringing you need to use a 50 Ohm termination.

author: K6EEP
author_rank: Contributor
timestamp: January 23, 2015, 07:00:16 pm
content: I am learning a lot. I hope the pictures and thread help others as well as me.Thank you for all your comments and help. Here is the latest pic with a BNC Tee on scope input and a 50ohm load on one leg and the signal on the other. Much better. What a difference between pic one and this one!

author: janoc
author_rank: Super Contributor
timestamp: January 25, 2015, 01:33:24 pm
content: Quote from: mij59 on January 23, 2015, 04:22:02 pmAh, well spottedDidn't notice the time base - at 2MHz the signal period is 500ns, what was K6EEP expecting to see there?

author: DIPLover
author_rank: Regular Contributor
timestamp: January 25, 2015, 02:13:24 pm
content: @K6EEP : you were rather quick to attribute your terrible results to chinese workers instead of to your own ignorance. Maybe that should be food for toughts...

author: mij59
author_rank: Frequent Contributor
timestamp: January 25, 2015, 02:23:27 pm
content: Think of it as an everlasting light bulb moment, no free energy required.

author: K6EEP
author_rank: Contributor
timestamp: February 04, 2015, 05:27:20 am
content: I have no regrets complaining about this piece of equipment. It is still junk. The front panel fell off.It is pretty obvious that I made a mistake in setting up my test. I don't need to have my nose rubbed in it.Well no worries I won't be posting again.

author: Lightages
author_rank: Unknown
timestamp: February 04, 2015, 05:56:32 am
content: Please don't be insulted and run away. You made a mistake in assessment. I do it sometimes too. If I get called on it I just admit it and move on. The generator might be constructed badly but it still might work within spec.

author: tautech
author_rank: Super Contributor
timestamp: February 04, 2015, 06:22:55 am
content: Quote from: K6EEP on February 04, 2015, 05:27:20 amYou've already made a valuable contribution warning us of the build quality.Thanks

author: DIPLover
author_rank: Regular Contributor
timestamp: February 04, 2015, 01:28:43 pm
content: Quote from: K6EEP on February 04, 2015, 05:27:20 amI think people should read the fucking manual before resorting to racist comments, and I will rub their nose in it every time thank you very much. We tolerate the Wun Hung Lo shit from Dave because he's Dave. Do your homework.The quality or non-quality of the gear you bought is irrelevant and should have been obvious from the price paid.

author: janoc
author_rank: Super Contributor
timestamp: February 04, 2015, 05:46:38 pm
content: Quote from: DIPLover on February 04, 2015, 01:28:43 pmPlease speak for yourself, unless you are using the royal "we".As far as I know, the "Wun Hung Lo shit" is meant to describe cheap crap made in a no-name factory somewhere in Asia and was neither said as a generalization of the quality of everything coming from there nor as a disparaging remark on people living there. So, please, do tone down your racial sensitivities here.There are places where calling out stereotypes and racism is warranted, but I think you have overstepped your bounds in your zeal here.

author: Pasky
author_rank: Regular Contributor
timestamp: February 04, 2015, 07:02:18 pm
content: Quote from: DIPLover on February 04, 2015, 01:28:43 pmI think jumping the gun and calling someone racist over something this silly is ignorant. I didn't see any racially charged material in his mistake.

author: rdl
author_rank: Super Contributor
timestamp: February 04, 2015, 07:15:44 pm
content: Indeed. Where exactly did the op mention "Chinese"?I think the front panel falling off may qualify it as "Wun Hung Lo shit", which can be made just about anywhere, by just about anyone.Quote from: DIPLover on January 25, 2015, 02:13:24 pm

author: DIPLover
author_rank: Regular Contributor
timestamp: February 04, 2015, 07:30:20 pm
content: OP shows a picture of "auto-set button induced aliasing" and immediately follows it by the comment : "Wun Hung Lo Factory strikes again".If you believe this was OK and I should not have called him out on blaming his poor results on "unnamed factory workers somewhere in Asia" (since apparently he did not specify Wun Hung Lo factory to be located in China...), then that's fine by me, I don't really care.Only after he announced he would pick his toys and go home because I had "rubbed his nose in it" (his ignorance, that is) did I call the comment racist. I said nothing about the person uttering the comment.But I still maintain, that these kind of comments, especially when used as "first resort" for explaining bad results, are lazy and tainted with racism.Just don't be lazy, do your homework.