Author Topic: The Rigol DS1052E  (Read 537136 times)

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TrentO

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Re: The Rigol DS1052E
« Reply #25 on: October 29, 2009, 10:12:15 pm »
Okay-- so I took the cover off--

Here are some tips--

1. The power button has to come off first! I removed it by slipping a 1.5mm Allen (hex) key between the adjacent cooling slots and under the power button, then pulling straight up with a pair of pliers. It took about 18 lbs. of force to remove it.

2. There is a external-case colored shim between the power connector and the external case. Gently pry between this shim and the external case to get past it-- the shim 'stays' there on the power supply, although it's loose. I have a really big (8M-pixel) picture, if anyone wants to see it. Do not remove the screws holding the power receptacle on-- otherwise, you'll have to spend time looking for the nut that used to be on the other side for no reason. I learned this one the hard way.

3. I didn't bother trying to save the "warranty void if broken" sticker-- for $400 bucks I didn't care so much. I used a commercial product called "OOPS!" to remove the "void" residue.

It took me about 10 minutes to figure out how to get things apart, without any scratches or signs of dis-assembly, apart from ruining the warranty sticker.

As for that burnt plastic smell-- I know where it comes from! They are apparently much more aggressive with the sanding now-- the ADC's and the same IC's in the analog-section (under the shielding) have been mechanically ground off, probably with some kind of rotary (Dremel) tool. There was plastic dust EVERYWHERE! This kind of shit really pisses me off-- Couldn't they vacuum afterwards? Using just your finger, you could write your initials. Also, being the sweaty-bastard that I am, I used surgical gloves during dis-assembly. It turns out, there was "No NEED" for that-- fingerprints, again, EVERYWHERE!  Also-- super cheap assembly hardware-- screws and the like.

And now for things of importance-- any perceivable difference between my 1052E, Dave's unit, and that other guy's 1102 (who's pissed off about the (re-) soldering job.) And YES there is difference. My unit, S/N: DS1ED113907XXX looks MORE like the 1102, than Dave's 1052. If you look at the analog section in the photographs provided by Dave, there is a 4-pin SMT relay labeled "Cosmo Y214S," right next to the BNC input. On my unit, that is replaced by a bigger relay exactly like that "NEC UD2-4," not too far from it. If I recall correctly-- that other guy's 1102 also has the bigger relay. Could this be the major functional difference that we all seek? Maybe not, but it would be interesting to note when they changed this and why. Anybody have a 100Mhz function generator that I could borrow for a day?

There also seems to be a 'repair' of sorts on the LCD controller IC-- someone (with really steady hands) soldered a piece of wirewrap wire between two points on that IC, and then glued the wire to the top of the IC.

Final note: I know that $400 US is a great price for a O-scope with these capabilities and features-- but I have not seen a final assembly this bad on anything that cost more that 10 bucks. Looking at the inside of my 28-year old Tektronix, you know that dudes/chicks with white-cotton gloves put that baby together in a 'clean' environment.

Pardon me while I go and bust-out the vacuum cleaner....

-Trent "the kinda guy that would (probably) also jump out of a perfectly good airplane" O.

P.S.: Note to the Rigol dudes that are undoubtedly reading this-- pick quality-control back up-- we notice.





 
« Last Edit: October 30, 2009, 04:44:42 am by TrentO »
 

Offline flolic

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Re: The Rigol DS1052E
« Reply #26 on: October 29, 2009, 10:44:24 pm »
Thanks for the tips, TrentO!
Few hi res pics of the inside would be nice, especially "canned" analog section. I will take apart my 100MHz scope when it arrive, so that we can make a comparison  ;)

Btw you can get rid of the plastic dust with the help of compressed air, DO NOT use vacuum cleaner!
 

TrentO

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Re: The Rigol DS1052E
« Reply #27 on: October 29, 2009, 11:31:22 pm »
flolic-- no vacuum cleaner, roger that. I just left it for now and put it back together. It still works.  ;D

I just used it to troubleshoot my Tektronix 2445.

I'll take it apart again for close-ups of the analog front-end, probably tonight.

I wouldn't worry about the EMS tracking thing-- It's total B.S.-- according to the USPS shipping label on the box, they got it an hour-and-a-half after it reached customs. EMS claims that customs held on to it for three days. I think someone at EMS is behind on the manual data entry.

It all worked out, but they're definitely not a FedEx, UPS, DHL, or even USPS.

Now actually having done something with it-- the fan is definitely noisy-- more so than most PC's, except for those on hi-flow-gamer CPU's. I'm also a big fan (no pun intended) of the "Modern" color-scheme/skin. And it's FAST!

Speaking of hi-flow-gamer CPU's/PC's-- I was thinking about changing that clock crystal to a 200Mhz one, and liquid-cooling that sucker....

-Trent

 

Offline EEVblog

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Re: The Rigol DS1052E
« Reply #28 on: October 30, 2009, 01:55:40 am »
@ TrentO
It quite amazing the difference. My unit is assembled very well indeed. No dust, no bad solder joints, no crap quality assembly hardware, no mode wires etc.
Please post the pics!

Dave.
 

TrentO

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Re: The Rigol DS1052E
« Reply #29 on: October 30, 2009, 03:47:27 am »
Ok-- I took it down to the individual components (only requiring one de-soldering operation,) took a few photos with my crap 'point-and-shoot' Kodak, and reassembled. And it still works!  ;D ;D

Not as bad as trying to take apart an HP-48 calculator, but still, IT's NOT (necessarily) EASY!!!

Additional dis-assembly tips--

Tools you'll need-- 1. T10 Torx screwdriver  2. T15 Torx screwdriver  (both narrow shaft- not the bit-based screwdrivers) 3. Electrical tape  4. 1.5mm "L" Allen/Hex-key  5. Soldering Iron  6. Desoldering pump or braid.  7. Small pliers  8. 14mm wrench (not socket) small adjustable wrench might be okay.

Basic steps--

1. Remove front panel knobs (make a 3" loop of electrical tape, and roll into a doughnut shape, then wrap around the inner shaft of each knob, brace the top of each knob with your other hand (to ensure that the force is axial to the shaft) then pull-- it takes about 20lbs of force to pull each knob.) I would seriously recommend against simply prying the buttons off-- you'll either damage the label-face, or damage the bottom of the knob, or worse-- damage the rotary encoders themselves. Note here-- the rotary encoders appear to be consumer-grade Alps units.

2. Remove the power switch with the allen-key and pliers, via the vent adjacent to the switch. Stabilize the switch button with your other hand here, as well, to ensure that the forces are on the same axis as the motion of the switch.

3. Remove case screws (qty 4). The ones under the handle are removable with the handle held at ~45deg-- trying to remove the handle first would most likely break it.

4. While pushing in the brown-colored power receptacle bezel (LIGHT pressure,) pull the cover off. Don't pry the cover over the black power receptacle with a screwdriver-- no need to-- it will only damage the case or bezel.

5. Remove the DB-9 jack screws. Note to Rigol-dudes-- Lock-Tite (blue) might make sense here-- I hate it when the jack screw comes off with the cable!

6. Remove the back shield-panel.

7. Remove the top shield-panel.

8. Remove the Fan.

9. Remove the power supply-- for me, unplugging the power cable to the main board took the most amount of time-- it's on there pretty good. Careful with the backlight connection-- there's not much room to disconnect that cable-- a 'third hand' might be helpful here.

10. Remove the five screws holding the front panel/bezel. Careful with the rubber overlay, don't touch the contact points.

11. Desolder the chassis to USB connector ground 'strap.'

12. Unscrew the 14mm nuts holding the panel-BNC connectors.

12.5 'unplug' the flex-pcb connections to the LCD and front panel-- the back-portion of each pcb connection lifts-up.

13. Unscrew and remove the main board. There you go!  Note-- there are two empty screw holes adjacent to the vacant header-pin locations. If you 'run out' of screws, look here. I believe these are vacant to accept a daughter-card of some kind. Logic probe?

14 Reverse the above to reassemble.


Caution and warning points-- 1. ESD sensitive device!!!  2. "Swift, but gentle" motions pulling on the power button and front-panel knobs.  3. Careful not to put too much pressure on the front knobs/nubs when the unit is face-down on your workbench.  4. Careful not to scratch the LCD face with loose crap on your workbench.  5. Careful not to burn a hole in anything plastic, while playing "light-sabre" with your soldering iron.

Thumbs up to Rigol for following Tektronix's lead, and making this an essentially Torx-screw only product. That Philips-guy can bite-me... The JIS dudes can bite-me even harder.

I take no responsibility for any damage that you may incur trying to execute the above steps. I don't think Dave would either.

Personalized assistance will be available to the owners of 1102 C/D/E's in exchange for detailed photos (of the O-scope innards, NOT of yourself.)

-Trent
 

TrentO

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Re: The Rigol DS1052E
« Reply #30 on: October 30, 2009, 03:53:15 am »
I'm emailing Dave the pictures of the analog section from my 1052E-- they're 2MB in size, and Dave's server only accepts 128KB attachments. Perhaps he can post them here, or somewhere? Don't expect too much-- I don't have a pro-grade macro-lens setup.

 

Offline desolatordan

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Re: The Rigol DS1052E
« Reply #31 on: October 30, 2009, 04:13:15 am »
I'm emailing Dave the pictures of the analog section from my 1052E-- they're 2MB in size, and Dave's server only accepts 128KB attachments. Perhaps he can post them here, or somewhere? Don't expect too much-- I don't have a pro-grade macro-lens setup.



or http://imageshack.us/
 

TrentO

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Re: The Rigol DS1052E
« Reply #32 on: October 30, 2009, 04:31:13 am »
Thank you, DesolatorDan.

Wow this whole Internet thing is amazing. Or... I'm just super lazy. Hey I just spent the last three hours taking apart my Rigol and discussing the steps! Cut me some slack.

The Analog (Analogue) Section-- (note the grey plastic residue all-over the place.)


The 'backside' of the card-- (fingerprints and plastic reside are most visible here.)


Both the fingerprints and plastic residue are embedded in flux--wiping/blowing will not dislodge them. And it wasn't me-- I was wearing surgical gloves the whole time!

 

Offline desolatordan

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Re: The Rigol DS1052E
« Reply #33 on: October 30, 2009, 05:06:24 am »
Thanks for the tips, TrentO!
Few hi res pics of the inside would be nice, especially "canned" analog section. I will take apart my 100MHz scope when it arrive, so that we can make a comparison  ;)

Btw you can get rid of the plastic dust with the help of compressed air, DO NOT use vacuum cleaner!

Why wouldn't you want to use a vacuum cleaner? Can it cause static buildup or something? Or just ineffective?
 

Offline flolic

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Re: The Rigol DS1052E
« Reply #34 on: October 30, 2009, 07:15:34 am »
Vacuum cleaner is ineffective, can cause ESD damage and you can very easily tear off some small SMT component if you accidentally touch PCB.
OTOH compressed air is joy to use, especially if it is from bigger size unit (that portable "briefcase" size air compressors without tank is no-go...). Canned air can be used too, but is not that effective as the real stuff.
 

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Re: The Rigol DS1052E
« Reply #35 on: October 30, 2009, 07:43:44 am »
flolic-- no vacuum cleaner, roger that. I just left it for now and put it back together. It still works.  ;D

I just used it to troubleshoot my Tektronix 2445.

I'll take it apart again for close-ups of the analog front-end, probably tonight.

I wouldn't worry about the EMS tracking thing-- It's total B.S.-- according to the USPS shipping label on the box, they got it an hour-and-a-half after it reached customs. EMS claims that customs held on to it for three days. I think someone at EMS is behind on the manual data entry.

It all worked out, but they're definitely not a FedEx, UPS, DHL, or even USPS.

Now actually having done something with it-- the fan is definitely noisy-- more so than most PC's, except for those on hi-flow-gamer CPU's. I'm also a big fan (no pun intended) of the "Modern" color-scheme/skin. And it's FAST!

Speaking of hi-flow-gamer CPU's/PC's-- I was thinking about changing that clock crystal to a 200Mhz one, and liquid-cooling that sucker....

-Trent



Likewise mine suposedly spent 3 days in customs in the UK yea right but this end was "out for delivery" on thursday night ! but did not get it till the monday... we were having postal striles here in the uk. I still say that a metal sheild around the supply would not go amiss, like others said its a great scope but clearly a CHEAP build
 

TrentO

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Re: The Rigol DS1052E
« Reply #36 on: October 31, 2009, 08:07:20 am »
Vacuum cleaner is ineffective, can cause ESD damage and you can very easily tear off some small SMT component if you accidentally touch PCB.
OTOH compressed air is joy to use, especially if it is from bigger size unit (that portable "briefcase" size air compressors without tank is no-go...). Canned air can be used too, but is not that effective as the real stuff.

I recall, "back in the day," when I used to install/maintain telco equipment, that we had an 3M ESD-safe vacuum cleaner that was kinda pricey for something that simply sucked air... A single replacement filter was more than a single day's pay-- that unit was supposedly useful for cleaning board-level stuff without fear of zapping anything.

I'm leaving my Rigol 'as-is' to remind me to buy the LeCroy or Tektronix O-scope next time.
 

GeekGirl

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Re: The Rigol DS1052E
« Reply #37 on: October 31, 2009, 10:10:19 am »

I'm leaving my Rigol 'as-is' to remind me to buy the LeCroy or Tektronix O-scope next time.


Shhhhhsssss, you will start us all drooling mentioning the L word ;)
 

TrentO

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Comparisons to a Tektronix TDS-220
« Reply #38 on: November 03, 2009, 12:49:28 am »
I just took delivery of a used Tektronix TDS-220, from a shady-looking character on eBay.

After having spent the last hour-or-so playing with it... I then decided to TAKE IT APAHT!

Initial observations, versus the Rigol DS-1052E--

1. The TDS-220 is a noticeably lighter-- maybe 2/3's the weight of the Rigol. Light is good. But my anxiety over losing either unit to a fall off-of my bench is high. (I have a hole pre-dug in my backyard just in case the cat knocks it over.)
2. The Rigol actually feels sturdier and more solid than the Tektronix.
3. The spinning action of the dials actually feel better on the Rigol, especially with the tactile 'bumps' on the v/div knobs.
4. The knobs themselves are better on the Tektronix-- the Rigol knobs are all a little off-axis, which causes the spin to be off-axis. (Shitty molding-job on the knobs-- the rotary encoders are good units.)
5. Color display on the Rigol, versus monochrome on the Tektronix-- I would choose color, of course! Much easier on the eyes.
6. Teeny-tiny sample depth on the Tektronix. Massive sample depth on the Rigol, but you need to navigate a menu to activate it.
7. Back-lit buttons on the Rigol, not lit on the Tektronix. Excellent for low-light environments. However, I find the bright-red run/stop button, when stopped, to be very annoying. It's simply too bright.
8.  No relays clicking (ever) on the Tektronix. Better for those days when you decide to work on your electronics projects in bed, without fear of waking your spouse.
9. More dedicated buttons on the Tektronix, in more 'traditional' locations. I did not have to read the manual to understand the basic operation of the Tektronix-- function is very much like the CRT analog oscilloscopes of yore. It took a fair amount of time to understand the Rigol-- a lot of nested menus.
10. USB-stick and USB-pc interface on the Rigol-- No challenge here-- advantage definitely Rigol.
11. NO output on my 'new' Tektronix-- I don't have the interface module.
12. The Rigol is faster on the display and menu navigation. However, there is less need to use the menus on the Tektronix... So in use, the Tektronix is faster and more convenient (for me.)
14. There appears to be MORE noise on the low v/div on the Tektronix than the Rigol. (Take that, Simon!)
15. Better rubber feet on the Tektronix-- My Rigol has harder rubber feet that don't grip very well. It slides-around more readily.

Observations after taking it apart--

1. The design is more efficient on the Tektronix--very little shielding in use, far less cluttered mainboard.
2. Although the interior plastic on the Tektronix is metalized, there is no over-all metal shielding-can like the rigol.
3. As expected, the build quality is higher on the Tektronix-- built by techs with cotton gloves, no after-the-fact soldering, no fingerprints, etc. In fact, my used Tektronix looks cleaner and newer on the inside that my new Rigol!
4. Much easier to take apart the Tektronix, than the Rigol-- less than a minute for the Tektronix, more than 1/2-hour (the first time) for the Rigol.
5. Better hardware, better materials on the Tektronix, but the Tektronix but it feels like an older design-- like the difference between a high-end VHS-VCR versus a cheap Blue-Ray player.
6. No rust after 7+ years on the Tektronix, but the shielding (edges) are already rusting on the new Rigol.
7. MOST IMPORTANTLY-- no loud-ass fan on the Tektronix.




So Trent's final analysis--
1. Advantage Rigol 1052E!  For all of its faults, $400 US ain't bad, especially for all those great features!
2. HOWEVER-- what I'll probably end-up using more-- the Tektronix TDS-220, because-- 1.) it's SILENT, and I wouldn't have to clean it like I do with my PC's every year; 2.) it's more convenient to use, especially for quick measurements, where I don't need to document the results of my tests.
3. What I'd actually tell other EE-types (and EE-groupie chicks) I use-- the Tektronix TDS-220. The intrinsic confidence is higher with the Tektronix. I would never tell the guys at the EE-Peninsula Club (downtown) that I actually own a Rigol.
4. IF I could only have ONE, I would probably choose the Rigol 1052E.... Or ditch both and get a new LeCroy WaveAce 212.  ;)

-Trent

« Last Edit: November 03, 2009, 01:10:19 am by TrentO »
 

Online Simon

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Re: The Rigol DS1052E
« Reply #39 on: November 03, 2009, 07:47:32 am »
you confirm my impression of the rigol, very good for the money but built cheaply, I suppose as always the move from analogue to digital is a bumpy one and not as straight foward as I would have hoped. but remember if for the sake of a bit more shielding it could have been better its a pity they didn't for another tenner,
 

TrentO

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Re: The Rigol DS1052E
« Reply #40 on: November 03, 2009, 11:40:57 am »
Simon,

After spending five hours troubleshooting an RS-232/UART issue (it turns out it was a software error in Lucio Di Jasio's Programming 32-bit Microcontrollers in C" book,) I must say that the Tektronix is much more friendly to those used to analog scopes. I validated my hardware concerns using the Tektronix immediately; trying to figure out the triggering modes on the Rigol took a bit more time. However, having done so, I have a greater appreciation for the capabilities of the Rigol. Still, it just isn't as intuitive to use as the TDS-220. As the even the newer Tektronix scopes seem maintain the same function keys, I think I'm beginning to really SEE what is meant by the expression-- "Tektronix really knows how to make a good scope." The business-oriented side of me says that Rigol had to make their scopes act and feel sufficiently different from Tektronix, so that they wouldn't get sued. The frosted side of me says that the Rigol dev team went features-crazy and stuffed this baby beyond the limit of what's practical in a 12" x 6" x 5" device. I hate to think what I (might) miss in future troubleshooting episodes, simply by fact of not being familiar with my gear. My new tagline for Tektronix: "Tektronix-- for EE's that don't wanna F*ck around!"

Either way-- I'm soooo happy with my decision to forsake the analog-scope world! If you're getting into the logic-based stuff, there's just no other way.
 

Offline EEVblog

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Re: The Rigol DS1052E
« Reply #41 on: November 04, 2009, 11:22:47 pm »
With regards to the Rigol fan, I recon it can probably be disconnected or dropped in speed, my unit doesn't even get warm.

With regards to the "cheap" construction of the Rigol, I have to disagree. My unit has a top class soldering job, and the component quality is top class also, no cheap asian substitutes. And the design and layout is excellent. Although it appears the soldering quality does vary between units as people are saying.
Even factoring in questionable soldering the quality on some units, the Rigol is far from being a "cheap" design.

There is no doubting the excellent usability of the TDS-210 series, that is why it's been the industries most popular digital scope from day one. It just shits me that more than decade later, and after several model improvements, the base model unit (TDS-1000B/2000B) STILL has a shitty 2.5KB memory!
They are clearly protecting the market for their mid range units.

Rigol on the other have no such hang-up's so you get 15K/1MB even on the bottom of the range unit.

Dave.
« Last Edit: November 04, 2009, 11:30:15 pm by EEVblog »
 

TrentO

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Re: The Rigol DS1052E
« Reply #42 on: November 05, 2009, 08:53:26 am »
I only wish that they used chrome-plated steel, or steel that was galvanized after the stamping process, NOT shaved the IC's (or at least cleaned up after themselves) and limited the fingerprints during manufacturing. To me, its a shame that they degraded their product so late in the process by cutting-corners like this-- I think they're only saving about $5.00 per unit by doing so. It works well for me so far, although the fan may take a little getting used to.


-Trent
 

Offline EEVblog

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Re: The Rigol DS1052E
« Reply #43 on: November 05, 2009, 11:25:29 pm »
For those interested:
http://www.dealextreme.com/details.dx/sku.30573
$412 with Free shipping worldwide.
That's the cheapest you can get it in Oz at least I believe.

Dave.
 

TrentO

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Maybe I just don't F'n get it?!
« Reply #44 on: November 06, 2009, 01:26:10 am »
I have been called "bank of dumb-shit" before, so someone PLEASE help me with this!!!

But first, a short preface-- I figured that by essentially 'screwing around,' and trying to measure everything in sight, would help me to learn the intricacies of using my new Rigol and, to a lesser extent my (new to me) Tektronix TDS-220. I had a piece of really high-end networking equipment-- a layer 3-7 intrusion prevention appliance with GigE capability that I took the cover off today, to see what was inside-- a large number of FPGA's, network processors and what not-- and about half-a-dozen SMT oscillator devices. Cool. Something I can measure, and if I only measured the OSC outputs, with little fear of screwing up my $20,000 network device!

Now, what I DON'T understand is how my 50-Mhz-rated Rigol 1052E could easily measure the clock on 25Mhz and 50Mhz as expected, but could also measure the clock on 66.6Mhz, 100Mhz, and 125Mhz! See pic of the 125Mhz displayed, auto-triggered and measured by my 1052E--



It had a little trouble measuring the 100Mhz oscillator output-- the level was lower and there was some jitter apparent-- but the the Rigol 1052 did display, auto-trigger and measure (steadily) see pic--



Now what is MOST interesting to me is that my Tektronix TDS 220, kept pace with the Rigol 1052E, EXCEPT for trying to measure the 100Mhz-- It simply could not do it!!!  It did fine with the 125Mhz, but it could not find an adequate input on the 100Mhz to trigger! Note-- I didn't photograph the screens from the Tektronix during these tests-- the monochrome is much harder to capture, but the output levels were pretty much the same-- I didn't see any attenuation or v-div differences (between the Rigol versus the Tektronix) across the 25-125Mhz range.

What the hell? This is the kind of shit that makes me want to give all this up and take up duck hunting instead. It just doesn't make any sense (TO ME.)

For those of you who have been reading this thread-- I did say earlier that the mainboard in my 1052E looked more like the mainboard in a 1102E-- could it be possible that my 1052E has a 1102E board in it, repaired and downgraded with lower software?

Or, more plausible-- I don't know what I'm doing, and getting am getting excited for no reason?

Someone please answer-- otherwise I wouldn't be able to sleep tonight.

Thanks,

-Trent

 
 

Offline EEVblog

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Re: The Rigol DS1052E
« Reply #45 on: November 06, 2009, 01:48:14 am »
That is normal, a 50MHz scope does not stop measuring signals at 50MHz, it's just 3dB down at 50MHz.
Check out the response graph someone posted in another thread, the 50MHz Rigol is only 6dB down at 100MHz, so will still easily display a signal.

The triggering issue?, well, that's just the nature of triggering. Sometime the scope gets it easy, sometimes you need to tweak it.

Dave.
 

TrentO

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Re: The Rigol DS1052E
« Reply #46 on: November 06, 2009, 03:05:56 am »
Dave, thanks for the incredibly fast response!

I'm still a little confused about the attenuation levels-- my expectations don't seem to jive with what I'm seeing--

The Rigol and the Tektronix show virtually the same waveform at 66MHz--




And at 100Mhz--




It's not until 125Mhz that any sort of difference becomes apparent--




I didn't take any pictures of the measurements at 25Mhz and 50Mhz, but the small error of margin between the Rigol and the Tektronix remains consistent-- the Rigol reads a little lower on the v/div for any given reading...

I seem to have missed that class on what -dB x means... could you explain?


Someone posted this on the equipment demo-center door, shortly after the executive management team gave me access--

ACHTUNG! Das machine is nicht fur gefingerpoken und mittengrabben.
Ist easy schnappen der springenwerk, blowenfusen und corkenpoppen mit spitzensparken.
Ist nicht fur gewerken by das dummkopfen.
Das rubbernecken sightseeren keepen hands in das pockets.
Relaxen und vatch das blinkenlights!


Also-- you were right about tweaking the triggering-- it took one full turn of the v-position dial to find the waveform, and like turning of the trigger dial for the Tek to finally get it. The Rigol got it automatically, each and every time!

« Last Edit: November 06, 2009, 03:12:55 am by TrentO »
 

Offline EEVblog

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Re: The Rigol DS1052E
« Reply #47 on: November 06, 2009, 04:10:57 am »
It's unlikely both scopes will have the same roll-off filter characteristics, so any differences would be normal. There are different types of analog filters and they can have different "orders" (rate or slope of attenuation with frequency).

dB is just a ratio, so instead of saying something is 0.5 times the value of something else, you can say it's "-6dB".
So if one scope reads 1V and the other scope reads 0.5V for the same signal then the say the second scope is "6dB down"

Some good rule of thumb numbers to remember:
3dB up or down is 0.707 (1/sqrt(2)) or 1.414 (sqrt(2))
6dB up or down is a half or two times (6dB=20 * log(0.5))
20dB up or down is 1/10th or 10 times (20dB=20* log(0.1))

And also, adding in dB's is like multiplying. So if something is 40dB down then it's 1/100th. etc
So if someone says something is 1 millionth, or 1ppm, or whatever, you can quickly use the rule of thumb to calculate it's -120dB (i.e. 6 (zeros) x -20dB) instead of using the formula dB=20*log(x)

Engineers like to talk in dB for many things!

Dave.
 

TrentO

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Re: The Rigol DS1052E
« Reply #48 on: November 06, 2009, 08:14:38 am »
Hallelujah! Yes! Yes! I SEE THE LIGHT!  (The band!)

at  25 Mhz, I see a ratio of 1.00, rigol/tektronix v-p-p
at  50 Mhz, I see a ratio of .97, rigol/tektronix v-p-p
at  66 Mhz, I see a ratio of .90, rigol/tektronix v-p-p
at 100 Mhz, I see a ratio of .66, rigol/tektronix v-p-p
at 125 Mhz, I see a ratio of .49, rigol/tektronix v-p-p

So my VERY rough, woefully unscientific results using peak-to-peak measurements comparing the two scopes shows a differential of -3dB approaching 100 MHz, and -6dB at 125 MHz. The world makes sense to me again!

Thanks for your help on this one Dave.

-Trent

 
 
 

Offline Dago

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Re: The Rigol DS1052E
« Reply #49 on: November 06, 2009, 09:00:33 am »
Btw. tip for TrentO (and others as well): Enable the frequency counter from Utility -> Counter ON, it is much more accurate than the measure -> Freq thing (I believe this measures the frequency from the waveform showing on the screen, but the counter counts it from a longer period).
Come and check my projects at http://www.dgkelectronics.com ! I also tweet as https://twitter.com/DGKelectronics
 


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