Author Topic: RPS2050 pen style scope review & teardown  (Read 16996 times)

0 Members and 1 Guest are viewing this topic.


Offline gtsili

  • Contributor
  • Posts: 36
  • Country: gr
  • A software/systems engineer revisiting electronics
Re: RPS2050 pen style scope review & teardown
« Reply #1 on: June 05, 2012, 10:41:33 am »
160 quid down the drain  :'( We got a teardown video but, I am really sorry for you Mike  :(
 

Online EEVblog

  • Administrator
  • *****
  • Posts: 29959
  • Country: au
    • EEVblog
Re: RPS2050 pen style scope review & teardown
« Reply #2 on: June 05, 2012, 10:52:33 am »
The ADC is a rebadged or ripoff AD9288 perhaps?

Dave.
 

Offline mikeselectricstuff

  • Super Contributor
  • ***
  • Posts: 12028
  • Country: gb
    • Mike's Electric Stuff
Re: RPS2050 pen style scope review & teardown
« Reply #3 on: June 05, 2012, 10:59:26 am »
The ADC is a rebadged or ripoff AD9288 perhaps?

Dave.
Does look somewhat similar.... even the graphics in the datasheet are clearly lifted from AD... Funny how identical the datasheet performance graphs are..,!
http://www.csmsc.com/info/chinese/adda/HWD9288.pdf
http://www.analog.com/en/analog-to-digital-converters/ad-converters/ad9288/products/product.html
Youtube channel:Taking wierd stuff apart. Very apart.
Mike's Electric Stuff: High voltage, vintage electronics etc.
Day Job: Mostly LEDs
 

Online EEVblog

  • Administrator
  • *****
  • Posts: 29959
  • Country: au
    • EEVblog
Re: RPS2050 pen style scope review & teardown
« Reply #4 on: June 05, 2012, 11:05:04 am »
Does look somewhat similar.... even the graphics in the datasheet are clearly lifted from AD... Funny how identical the datasheet performance graphs are..,!
http://www.csmsc.com/info/chinese/adda/HWD9288.pdf
http://www.analog.com/en/analog-to-digital-converters/ad-converters/ad9288/products/product.html

*snort*

Dave.
 

Offline Bored@Work

  • Super Contributor
  • ***
  • Posts: 3932
  • Country: 00
Re: RPS2050 pen style scope review & teardown
« Reply #5 on: June 05, 2012, 11:21:44 am »
If you go to the manufacturer's website http://www.realt.cn you are pestered with an invitation for a live chat after looking at some products. Maybe an opportunity to provide the manufacturer with some feedback :)

And here is the original 14 pages manual http://realt.cn/images/load/RPS%E7%A4%BA%E6%B3%A2%E7%AC%94%E7%94%A8%E6%88%B7%E6%89%8B%E5%86%8C.pdf

Google translate doesn't work too great, but some mysteries can be decoded with a side-by side comparison of original and translation. E.g page eight says the blop on left of the display is the trigger status. And the strange heart shaped icon is supposed to be a USB plug and should show USB connection status.

http://translate.google.com/translate?sl=auto&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Frealt.cn%2Fimages%2Fload%2FRPS%25E7%25A4%25BA%25E6%25B3%25A2%25E7%25AC%2594%25E7%2594%25A8%25E6%2588%25B7%25E6%2589%258B%25E5%2586%258C.pdf

There is also some mentioning of test signals the thing is capable of generating.
I delete PMs unread. If you have something to say, say it in public.
For all else: Profile->[Modify Profile]Buddies/Ignore List->Edit Ignore List
 

Offline Lightages

  • Supporter
  • ****
  • Posts: 4295
  • Country: ca
  • Canadian po
Re: RPS2050 pen style scope review & teardown
« Reply #6 on: June 07, 2012, 03:48:23 am »
First off Mike, sorry for even seeing this thing in DX. I had no idea it could be sooooooo bad. By buying this hunk of shit you have saved me the trouble and money down the drain, I have the Wittig Oszifox Penscope, actually two of them. For the $30USD I paid for each, they look like 1000x better value for the money, even from 90s technology!

You took a bullet for me so to speak, I guess my wallet is on the line the net time I see something "interesting".
 

Offline A Hellene

  • Frequent Contributor
  • **
  • Posts: 591
  • Country: gr
Re: RPS2050 pen style scope review & teardown
« Reply #7 on: June 07, 2012, 11:10:44 am »
I can feel your pain, Mike...

Anyway, thank you for the teardown of that pen-scope, which strongly reminded me of the RadioShack ProbeScope I had purchased in the late nineties for USD ~80, if I remember correctly. The ProbeScope was a 20Msps device, with 50ns..1.0ms timebase and 1V/10V/100V AC/DC input range, pen-scope/voltmeter that run on a 12V/20..100mA external power supply (its PCB run on 5.0V). Its accuracy was laughable, but it was very useful for the reverse engineering of PCBs, I used it for.

This is the ProbeScope PCB:


ProbeScope v4.1 (PCB v6.2, 32nd week of 1996)

At the top left of the picture can be seen my botch-work of adding a switchable 9.0 Mohm (= 4.7M + 4.3M) input resistor with a couple of AC compensating capacitors that form a 10:1 resistive/capacitive divider with the 1.0 Mohm device input, in order to expand the 100Vpp max. input range and to become able of using ProbeScope to troubleshoot the CDI/TCI motorcycle ignition controllers I used to repair and upgrade by that time.

As expected, of course, I managed to kill the device by accidentally touching a 300VDC output line of a CDI DC/DC converter while I was probing the low voltage section of the PCB, with the 9.0 Mohm front-end bypassed...


-George
Hi! This is George; and I am three and a half years old!
(This was one of my latest realisations, now in my early fifties!...)
 

Offline Lightages

  • Supporter
  • ****
  • Posts: 4295
  • Country: ca
  • Canadian po
Re: RPS2050 pen style scope review & teardown
« Reply #8 on: June 07, 2012, 02:46:46 pm »
That is the same as the Wittig Penscope. Mine is actually the Radioshack branded one too. Yes the accuracy was far from good but it still is a better buy than the unfortunate pile of crap in this review.
 

Offline A Hellene

  • Frequent Contributor
  • **
  • Posts: 591
  • Country: gr
Re: RPS2050 pen style scope review & teardown
« Reply #9 on: June 07, 2012, 03:47:47 pm »
Yes, I saw that; after posting my message above, I searched for information about the Oszifox Penscope.
Of course, I bought mine not for $30 but for $80 in '97; and I am too lazy now to find out the '97 rates and adjust the price in today's currency value... If I remember correctly, it was designed by some German firm and was branded and sold by Tandy/RadioShack. Does the PCB of yours have the same chips and markings?


-George
Hi! This is George; and I am three and a half years old!
(This was one of my latest realisations, now in my early fifties!...)
 

Offline ju1ce

  • Regular Contributor
  • *
  • Posts: 94
  • Country: fi
Re: RPS2050 pen style scope review & teardown
« Reply #10 on: June 07, 2012, 06:11:52 pm »
Thanks for the video Mike.
 

Offline Lightages

  • Supporter
  • ****
  • Posts: 4295
  • Country: ca
  • Canadian po
Re: RPS2050 pen style scope review & teardown
« Reply #11 on: June 08, 2012, 02:43:44 am »
A Hellene:

I will be posting another thread to not hijack Mike's
 

Offline nukie

  • Frequent Contributor
  • **
  • Posts: 775
  • Country: au
Re: RPS2050 pen style scope review & teardown
« Reply #12 on: June 08, 2012, 04:46:41 am »
Motorola engineers.
 

Offline free_electron

  • Super Contributor
  • ***
  • Posts: 7240
  • Country: us
    • SiliconValleyGarage
Re: RPS2050 pen style scope review & teardown
« Reply #13 on: June 08, 2012, 06:34:23 am »
Wittig is still around... they seem to come and go... sell rebranded scopes.
Professional Electron Wrangler.
Any comments, or points of view expressed, are my own and not endorsed , induced or compensated by my employer(s).
 

Offline Bored@Work

  • Super Contributor
  • ***
  • Posts: 3932
  • Country: 00
Re: RPS2050 pen style scope review & teardown
« Reply #14 on: June 08, 2012, 07:23:16 am »
Wittig went bancrupt around 2006 or 2007. At that time the W2000 or W2000A oscilloscope firmware source code made it to the community and became the start of a community project to fix/rewrite it.

The Wittig family/brothers opened a new company, Welec, and kept selling W2000A oscilloscopes. Whether that was NOS they took over from Wittig, or a new production run is anyones guess. Welec hasn't come up with anything new since they started in 2007, just selling the old Wittig W2000As.
I delete PMs unread. If you have something to say, say it in public.
For all else: Profile->[Modify Profile]Buddies/Ignore List->Edit Ignore List
 

Offline Bonati

  • Newbie
  • Posts: 2
  • Country: us
    • Bonati Mastering
Re: RPS2050 pen style scope review & teardown
« Reply #15 on: June 08, 2012, 01:47:02 pm »
(first post, hi everyone)

Thanks Mike, love your videos. Stay angry! Would love a video tour of your shop sometime if you're ever up for it.

 

Offline free_electron

  • Super Contributor
  • ***
  • Posts: 7240
  • Country: us
    • SiliconValleyGarage
Re: RPS2050 pen style scope review & teardown
« Reply #16 on: June 08, 2012, 03:17:16 pm »
Like i said.. They come and go ... Go bankrupt, come back under different name, disappear again, come back again..

The ws2000 does have a real vga screen 640*480 as opposed to qvga 320 240
Professional Electron Wrangler.
Any comments, or points of view expressed, are my own and not endorsed , induced or compensated by my employer(s).
 

Offline billclay

  • Regular Contributor
  • *
  • Posts: 82
  • Country: us
Re: RPS2050 pen style scope review & teardown
« Reply #17 on: June 11, 2012, 05:11:02 am »
Mike, your review was great!  Not owning one of these, how do you easily view the display while probing?  You probe straight down (or at a slight offset) and you have to twist your head at a strange angle to read the display?  Doesn't sound fun if the space you are working in is tight, after all you said it is suited for field work.

Oh, and BEEP, BEEP, BEEP, BEEP, BEEP, BEEP, BEEP, BEEP, BEEP!
 

Offline Hypernova

  • Supporter
  • ****
  • Posts: 654
  • Country: tw
Re: RPS2050 pen style scope review & teardown
« Reply #18 on: June 11, 2012, 06:37:46 am »
The OLED used appears to be the Crystalfontz CFAL12864N-A-B4 (http://www.crystalfontz.com/product/CFAL12864NAB4)

I wonder if they got the ATmega8 there just to handle the scroll wheel and stuff, it's in a pretty bad position though since having it there before the ADC would probably introduce some noise and may  be the reason the readings look a bit wobbly sometimes. Pretty silly design at the system level, there is no reason why they need to have more than one MCU in the whole thing, it may even be possible to embedded that into the FPGA as a softcore.
 

Offline steve_w

  • Regular Contributor
  • *
  • Posts: 190
  • Country: au
Re: RPS2050 pen style scope review & teardown
« Reply #19 on: June 11, 2012, 06:42:37 am »
Mike,

Good review, keep up the good work.

regards

SW
So long and thanks for all the fish
 

Offline T4P

  • Super Contributor
  • ***
  • Posts: 3706
  • Country: sg
    • T4P
Re: RPS2050 pen style scope review & teardown
« Reply #20 on: June 11, 2012, 07:10:05 am »
The OLED used appears to be the Crystalfontz CFAL12864N-A-B4 (http://www.crystalfontz.com/product/CFAL12864NAB4)

I wonder if they got the ATmega8 there just to handle the scroll wheel and stuff, it's in a pretty bad position though since having it there before the ADC would probably introduce some noise and may  be the reason the readings look a bit wobbly sometimes. Pretty silly design at the system level, there is no reason why they need to have more than one MCU in the whole thing, it may even be possible to embedded that into the FPGA as a softcore.

It's even more stupid to pack it into that tiny oled display, the oled display would be better used for other things
 

Offline mikeselectricstuff

  • Super Contributor
  • ***
  • Posts: 12028
  • Country: gb
    • Mike's Electric Stuff
Re: RPS2050 pen style scope review & teardown
« Reply #21 on: June 11, 2012, 07:59:15 am »
Mike, your review was great!  Not owning one of these, how do you easily view the display while probing?  You probe straight down (or at a slight offset) and you have to twist your head at a strange angle to read the display?  Doesn't sound fun if the space you are working in is tight, after all you said it is suited for field work.

Oh, and BEEP, BEEP, BEEP, BEEP, BEEP, BEEP, BEEP, BEEP, BEEP!
I don't think display readability is a problem - unless you're in a deep, tight space you can easily see the display. One thing that would improve it would be to have the display nearer the tip. 
Youtube channel:Taking wierd stuff apart. Very apart.
Mike's Electric Stuff: High voltage, vintage electronics etc.
Day Job: Mostly LEDs
 

Offline mikeselectricstuff

  • Super Contributor
  • ***
  • Posts: 12028
  • Country: gb
    • Mike's Electric Stuff
Re: RPS2050 pen style scope review & teardown
« Reply #22 on: June 11, 2012, 08:00:57 am »
Quote from: DaveXRQ link=topic=8762.msg119758#msg119758
It's even more stupid to pack it into that tiny oled display, the oled display would be better used for other things
[/quote
It is annoying that only half the probe height is display - a display that filled more of the case height would be a big improvement.
Youtube channel:Taking wierd stuff apart. Very apart.
Mike's Electric Stuff: High voltage, vintage electronics etc.
Day Job: Mostly LEDs
 

Offline amyk

  • Super Contributor
  • ***
  • Posts: 6537
Re: RPS2050 pen style scope review & teardown
« Reply #23 on: June 11, 2012, 08:18:46 am »
They probably chose the display size because it's a very common size in MP3 players and so available for really cheap.

As for the 2 controllers, my guess is they designed one part with the FPGA and ADC controlled by one, and another team designed the other part with the UI and used another to control that. Given the state of the firmware, they're probably not skilled enough to integrate everything into one FPGA; many Chinese companies are like this, they know how to connect parts together but are awful at writing the firmware for them.

Making a sound with every UI action is another one of those things I've seen a lot in other consumer electronics like phones and cameras. Maybe Chinese factories and electronics labs are loud places, but at least they could have an option to disable it...
 

Offline saturation

  • Super Contributor
  • ***
  • Posts: 4788
  • Country: us
  • Doveryai, no proveryai
    • NIST
Re: RPS2050 pen style scope review & teardown
« Reply #24 on: June 19, 2012, 07:16:41 pm »
Thanks, Mike, enjoyed it quite a bit.  As you say, it had great potential as a hand held quick check scope in the $200 range were there are still few in the market [ Uni-T UT81D and the Vellemans, AFAIK.]  But, it does look like it needs more work.
« Last Edit: July 22, 2014, 01:41:38 pm by saturation »
Best Wishes,

 Saturation
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf