GW Instek GOS 635G 35Mhz Dual Channel Analog Scope Query - Page 1
Forum section: electronics / testgear

author: aryasridhar
author_rank: Regular Contributor
timestamp: April 12, 2015, 06:54:31 am
content: Hi Guys,This is probably my first post here, and I recently acquired a GW Instek GOS 635G 35Mhz Dual Channel Analog Scope for 150 USD.Here's how the scope looks....the condition is great except that there is no stand with it..I did some tests to figure out if it is in working order, and seems to be working fine to me, however I am unsure if it is properly calibrated, I am posting a video down here, would you guys mind checking it out and let me know if it looks calibrated please?The Unit calibration point output is @ 2v Peak to Peak Voltage @ 1Khz.Here's the video with the reading on the scope..https://www.youtube.com/watch?v=BqtUfDGLLlY&feature=youtu.beRegardsArya

author: aryasridhar
author_rank: Regular Contributor
timestamp: April 12, 2015, 03:21:27 pm
content: Can anyone please help me out?

author: PeterFW
author_rank: Frequent Contributor
timestamp: April 12, 2015, 03:44:18 pm
content: Quote from: aryasridhar on April 12, 2015, 03:21:27 pm20mV are 0.02V.There are 8 divivisions on the screen and you set it to 0.02V/div.That means only 0.16V (8x0.02) of your 2V signal can be displayed on the screen.Same goes for the timebase, wrong setting.But either way, what is on the screen does not look like a squre wave on either setting.Set it to 1V per division and turn the timebase up and down until you see a square wave.But you need to use a proper probe to test it. that calibration point on the front is to calibrate the probe you are using, not the instrument itself.

author: tautech
author_rank: Super Contributor
timestamp: April 12, 2015, 08:02:38 pm
content: Quote from: PeterFW on April 12, 2015, 03:44:18 pm+1What Peter said.Unless the scope has been damaged by misuse it should be accurate enough for now.Show us the correct Cal waveform to be sure. Photo is all we need.Adjustment of scopes is not a simple matter and must not be attempted without the correct equipment.Your lead will be OK for "checking" basic LF functionality and some other LF work ONLY.Get a pair of P6100 probes from eBay or Aliexpress ~15USD a pair delivered.

author: aryasridhar
author_rank: Regular Contributor
timestamp: April 13, 2015, 02:08:45 am
content: Thank You for the inputs I have already ordered the P6100 pair for 12 bucks...And after I had posted the video...I did another one with .5v/div and .5ms on the timebase with DC coupling, Here is an image of it, I shall do it as Peter said and shall post another image of it.Also do you see that the trace is a bit tilted towards the right, I did adjust it with the trace rotation pot, but it still isn't perfectly straight as I'd like it to be, any suggestions on that?

author: PeterFW
author_rank: Frequent Contributor
timestamp: April 13, 2015, 12:22:04 pm
content: Quote from: aryasridhar on April 13, 2015, 02:08:45 amThats ok i think, try that again when you got the real probes, that test clip is not that well suited to this task.

author: aryasridhar
author_rank: Regular Contributor
timestamp: April 13, 2015, 06:02:58 pm
content: Quote from: PeterFW on April 13, 2015, 12:22:04 pmSure, I am waiting for the probes to arrive, hopefully in a week to try out the tests...

author: tautech
author_rank: Super Contributor
timestamp: April 13, 2015, 07:39:06 pm
content: As you see the waveform and calibration look plenty good enough to trust the scope for work.Trace rotation will tilt the entire waveform.It is used to line up the wavefprm with the graticules so accurate measurements can be made.Look at the Oscilloscope training class in the Beginers board, there is much good info there.