Products > Test Equipment
Gw Instek GDS2204E (200MHz 4 channel DSO) review
nctnico:
--- Quote from: markone on February 02, 2016, 11:50:59 am ---
--- Quote from: wraper on February 02, 2016, 11:24:02 am ---I'd prefer non shielded Instek over siglent rust. Also, from what I have read, it seem to use quasi-resonant SMPS topology, so the need for the shielding should be significantly reduced.
--- End quote ---
Watching to Dave's 1000B teardown video @31:25 you can see some quite strange periodic noise stuff, i'm wondering if it comes from PSU, that seems to be identical to the one mounted on GDS2000E family.
Regardless of the switching PSU's topology you always have high dV/dT circuit traces, avoid shieldind is not an option without implications, also for safety reason.
If some capacitor blows out, with open frames solution like that the whole instrument is involved.
--- End quote ---
It's not like every capacitor explodes at some point (especially since they have safety vents). Also the input circuitry is well shielded in a metal box so there really is no noise visible from the PSU with the inputs open on my GDS2204E. It is hard to tell where the artifacts Dave shows come from. First of all there are signal display issues in the firmware of the scope Dave is showing and secondly he noticed the circuitry is slightly different so that could also be a source of noise coupling into it. Furthermore it seems Dave never has opened a Tektronix TDS500/600/700 series scope; in those scopes Tektronix has also used ribbon cable to distribute the power (a lot!) to various parts of the scope. For as long as you stay within the maximum voltage and current rating of a connector it is fine to use whatever connector to distribute power.
@Achmed99: I think the letter E is for Economy.
markone:
--- Quote from: nctnico on February 02, 2016, 12:38:30 pm ---It's not like every capacitor explodes at some point (especially since they have safety vents). Also the input circuitry is well shielded in a metal box so there really is no noise visible from the PSU with the inputs open on my GDS2204E. It is hard to tell where the artifacts Dave shows come from.
--- End quote ---
Yes, sure, luckily not all capacitor explodes at some point but ...just in case.
Times ago it happened to me that a brand new Panasonic fax machine had a PSU capacitor suddenly failed spreading electrolyte liquid through the vents everywhere inside the box, ruining everything it touched, quite toxic smell inside the room !.
Of course it was swapped under warranty.
So you can confirm that your scope is not affected from the same strange noise that Dave spotted in its review ?
And, just out of curiosity, have you bought your from TME ?
nctnico:
I have no weird noise on my scope. I have attached some screendumps with the inputs open and set to 1mV/div at various time/div settings. Acquisition mode is set to sample and the variable persistence set to 240ms. But note that I have (newer) beta firmware in my scope!
tequipment:
E is the economy version but really its just a new scope version. In some ways it has better specs.
Also it had a 20% price drop yesterday on our site www.tequipment.net
Thanks
Evan Cirelli
TEquipment.NET
nctnico:
It seems the beta firmware got finalised into version 1.24 which was released a couple of days ago together with a new feature (seperate download) which shows the FFT result and the traces in a seperate window. I have not had the time to see if there are more new features in this firmware release.
I did however made a slight modification to the fan. It started resonating into the casing which made an annoying sound. Instead of going for a new fan I choose to change the mounting using rubber universal fan mounts: http://uk.farnell.com/duratool/dtrfmm-1/fan-mount-universal-4-5mm-pk50/dp/2472730 These soft rubber mounts decouple the fan from the casing so that inbalances in the fan do no get amplified by the casing.
I used the remaining pieces of the fan mounts to create stand-offs for the other 2 holes of the fan to keep it a bit more in place. The end result is a much quieter scope. And the best part is that I have 48 of these fan mounts left for other projects/equipment!
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