Author Topic: EEVblog #824 - GW Instek GDS-1000B Oscilloscope Teardown  (Read 38990 times)

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Online wraper

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Re: EEVblog #824 - GW Instek GDS-1000B Oscilloscope Teardown
« Reply #75 on: June 22, 2016, 10:50:45 am »
It also seems the direction of the fan on the GDS-2000E and GDS-1000B is different but it wouldn't surprise me if it turns out Dave's teardown victim is from a very early production (test) run.
Quiet likely, in my newer GDS-2000E scope, metal chassis is a little bit different than in 1054B from teardown. And as it looks like, this newer chassis is fully compatible with both GDS-1000B and GDS-2000E. However chassis in the scope which Dave got, is not compatible with GDS-2000E because of the few PCB mounting points lacking. Dave wondered why there wasn't one screw being present, probably because there is no mounting point there on the newer chassis as this mounting point is not compatible with GDS-2000E PCB, but they already used assembly procedure for newer chassis. Regret for not taking a picture of the bare chassis. Probably there is a hole for a screw to mount that flipping in the breeze plastic spacer Dave complained about. EDIT, in a few days will get a new fan for lower noise. Likely will check this out when disassembling the scope again.
« Last Edit: June 22, 2016, 11:06:51 am by wraper »
 

Offline saturation

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Re: EEVblog #824 - GW Instek GDS-1000B Oscilloscope Teardown
« Reply #76 on: June 23, 2016, 02:28:37 pm »
Some thoughts on critics made on this thread by others.

Overall economy design: makes little difference if it does not impact measurement integrity, longevity, EMC and safety compliance.  Performance testing on EEVblog #824 was not extensive, but elsewhere on eevblog forum shows both 1000B and 2000E does what its spec sheet says it does, and few bugs of concern.

Hopefully the discussion will interest Dave in a shootout between 1000B and the other scopes in his lab.

Longevity criteria are difficult to quantify, we can only qualify its long term quality by the reputation of the manufacturer and examining the teardown. 

In general, GWInstek devices have a reputation for very long lifetimes, regardless of our concern for their choice of internal components or design choices. 

Nevertheless, the components on the PCB appear to be good quality and make.  Instek devices rarely have any problems with their chassis, such as cracked knobs, or erratic rotary encoders such reported on the Rigol 1054e.

The fan is in an odd place, true, but the scope remains cooler than the Rigol 1052e to touch and vents as shown in the douglasfim post video.

My unit is also quieter than the Rigol 1054e.

EMC and safety were done by GWInstek as CE certificates only, and GWInstek tends to live up to CE conformity.   Nevertheless Lack of NRTL listing could be a problem in some workplaces due to liability, but this DSO is CAT1 device only, so there is no practical risk to users with proper use.

EMC could be a problem but if it were it would appear as unintended pickup by a DUT or probe cables.  A quick check of near field emissions show it highest right atop the unshielded top portion of the power supply, the highest being -50dBV rms at 60kHz.

Practically speaking, if emissions were higher it be illegal to sell in the USA by FCC regulations.

Concerned users can buy conductive tape, about $10 a roll, and line the interiors of the plastic rear case and ground it to improve the EMC.

FWIW, the Rigol 1052e is TUV listed and has no emissions I can detect from its all metal internal chassis.

As pointed out in another review, these series use a off the shelf Taiwan made Lytec PSU model lp6304 which has its own CE safety and EMC certificate.

Chassis: reminds me of Keysight Infiniivision 2000 series. 2000E and 1000B series have identical basic mold.  Like some Infiniivision models, there are buttons that do nothing but are cheap enough not remove during chassis assembly.  As an economy move, only minor changes need be made on the mold to create a new chassis, and while distracting, the non-functional buttons do not impact performance.

The overall size, being tall and wide, makes it less cramped to work fingers with and uses less bench floor space.

The metal frame is mostly infront of the scope as a shield, PCB mounts and structural rigidity.  It does a good shielding job, the scope lives up to its noise budget of ~500uVpp, this is at maximum gain too, with channels plugged with 50 ohm terminators and tested also with the supplied probes connected and shorted, regardless not measured with the channels left open circuit.

So in summary the striking economy moves in this series are:

Single mold chassis for the entire 1000B and 2000E series
Lack of third party safety and EMC certificates
Reduction in metal chassis surrounding the DSO core
Zync SoC
off the shelf PSU



« Last Edit: June 23, 2016, 04:32:46 pm by saturation »
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Offline bitseeker

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Re: EEVblog #824 - GW Instek GDS-1000B Oscilloscope Teardown
« Reply #77 on: June 23, 2016, 07:34:45 pm »
The overall size, being tall and wide, makes it less cramped to work fingers with and uses less bench floor space.

It also enables per-channel vertical controls, a definite win for usability. :-+
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Offline nctnico

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Re: EEVblog #824 - GW Instek GDS-1000B Oscilloscope Teardown
« Reply #78 on: June 23, 2016, 07:41:20 pm »
I wouldn't call an off-the-shelve PSU a downside. Keysight does the same in scopes which are much (like 50 times) more expensive. IMHO using an off-the-shelve PSU allows to benefit from the experience from others when it comes to using SMPS architectures which produce much less emissions and SMPS reliability.
« Last Edit: June 23, 2016, 07:45:32 pm by nctnico »
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Offline Brumby

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Re: EEVblog #824 - GW Instek GDS-1000B Oscilloscope Teardown
« Reply #79 on: June 24, 2016, 12:06:01 am »
I wouldn't call an off-the-shelve PSU a downside. Keysight does the same in scopes which are much (like 50 times) more expensive. IMHO using an off-the-shelve PSU allows to benefit from the experience from others when it comes to using SMPS architectures which produce much less emissions and SMPS reliability.

I would agree here.

If you have a tried and true solution that meets or exceeds the specifications required, has proven itself in the field and is available for use, why re-invent the wheel?

What comes after the PSU is where the design effort is best spent.
 

Offline tautech

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Re: EEVblog #824 - GW Instek GDS-1000B Oscilloscope Teardown
« Reply #80 on: June 24, 2016, 12:17:48 am »
I wouldn't call an off-the-shelve PSU a downside. Keysight does the same in scopes which are much (like 50 times) more expensive. IMHO using an off-the-shelve PSU allows to benefit from the experience from others when it comes to using SMPS architectures which produce much less emissions and SMPS reliability.

I would agree here.

If you have a tried and true solution that meets or exceeds the specifications required, has proven itself in the field and is available for use, why re-invent the wheel?

What comes after the PSU is where the design effort is best spent.
::)
Reliability.

So you haven't read this thread?
https://www.eevblog.com/forum/repair/keysight-mso7034b-teardown-and-repair/

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Offline Brumby

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Re: EEVblog #824 - GW Instek GDS-1000B Oscilloscope Teardown
« Reply #81 on: June 24, 2016, 04:53:58 am »
I thought I covered the reliability aspect...
 

Offline saturation

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Re: EEVblog #824 - GW Instek GDS-1000B Oscilloscope Teardown
« Reply #82 on: June 24, 2016, 11:43:45 am »
I agree, 100%.  I did not mean it negatively, rather its part of their economizing.  In fact, it makes it easier to replace should it go wrong.  Why redesign what someone specializes in?

If one were to compare the 1000B vs the Rigols 1054Z development processes, one gets an idea the the economizing done by Rigol was to rush it to market.

For GWInstek, the engineers did the cost cutting purposefully and took care that it did not affect the scopes performance.

The use of the Zync SoC reduces parts count considerably, increasing its overall reliability and likely ease of fixing problems, should it happen.

Another item is the disassembly of the chassis, as shown by Dave's eevblog teardown, is fairly quick and easy  to get to the PSU.

The Lytec supply does not have a replaceable fuse but because removing the chassis is easy its quick to get to and replace or repair, but I rarely have ever seen a PSU for a DSO malfunction except in very old devices.


I wouldn't call an off-the-shelve PSU a downside. Keysight does the same in scopes which are much (like 50 times) more expensive. IMHO using an off-the-shelve PSU allows to benefit from the experience from others when it comes to using SMPS architectures which produce much less emissions and SMPS reliability.
« Last Edit: June 24, 2016, 12:06:04 pm by saturation »
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