Author Topic: GW Instek GOS-653G Display Distortion  (Read 1721 times)

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Offline Branqazwsx

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GW Instek GOS-653G Display Distortion
« on: January 20, 2017, 04:20:08 am »
I have a GW Instek GOS-653G analog oscilloscope that was sitting in storage for a few years. I went to use it today, when I discovered there was a problem with the display. The upper right of the display is distorting the traces on the screen. It distorts with or without a probe or signal. It might be operator error, because its been so long since I used it. Does anyone have a thought to what the problem might be. See my video for the problem:



User manual: http://www.gwinstek.com/en-global/Download/DownloadFile/DownloadFile/download%23_%2301_Oscilloscope%23_%2304_GOS%23_%2382OS-658G0MG.pdf
 

Offline JXL

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Re: GW Instek GOS-653G Display Distortion
« Reply #1 on: January 20, 2017, 05:01:59 am »
Check for magnetic field near the CRT
 

Offline retired tech

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Re: GW Instek GOS-653G Display Distortion
« Reply #2 on: November 12, 2017, 12:43:31 am »
Like JXL said,might be a magnetic field(around mu-metal shield),or,I hope not,a dropped deflection plate.An old trick is to use a soldering gun(transformer type),turn it on and bring it close to the shield and gradually move it away from it.A foot or so before turning the gun off should do it.This was called degaussing in the old days.
 

Offline 001

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Re: GW Instek GOS-653G Display Distortion
« Reply #3 on: November 15, 2017, 07:23:50 pm »
similar problem

how can I fix it?
 

Online Gyro

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Re: GW Instek GOS-653G Display Distortion
« Reply #4 on: November 15, 2017, 07:48:15 pm »
That's trace rotation - there should be a preset scredriver adjustment pot for it (often front panel, sometimes internal).

P.S. Your scope probe compensation is incorrectly adjusted too.   ;)

EDIT: If it is the same scope as the OP's, according to the manual, it is the the control marked 'Trace Rotation' (5) on the front panel!
« Last Edit: November 15, 2017, 07:54:28 pm by Gyro »
Chris

"Victor Meldrew, the Crimson Avenger!"
 
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Offline 001

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Online Gyro

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Re: GW Instek GOS-653G Display Distortion
« Reply #6 on: November 15, 2017, 07:57:00 pm »
@001: It really, really helps to save peoples time IF YOU DON'T KEEP DOUBLE POSTING QUESTIONS!  |O
Chris

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Offline 001

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Re: GW Instek GOS-653G Display Distortion
« Reply #7 on: November 15, 2017, 10:18:33 pm »
Ok ok  :-+
Thanx
 

Offline oldway

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Re: GW Instek GOS-653G Display Distortion
« Reply #8 on: November 16, 2017, 11:23:57 am »
Mu metal offers small coercive force, nominal core losses and small remanence. For this reason, I don't think it is coming from a magnetic field.
It seems to be a bad CRT.

But you should check first the signals at the vertical and horizontal deflection plates with another oscilloscope to be sure.
 
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