EEVblog #553 - Mailbag - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: December 02, 2013, 01:31:07 pm
content: DIN 41612 Roth Electronics Extender Card:http://docs-asia.electrocomponents.com/webdocs/068f/0900766b8068f80e.pdfLichtenberg Figure:http://en.wikipedia.org/wiki/Lichtenberg_figurehttp://focusdesigns.com/Self Balancing UnicycleTektronix 213 oscilloscope:http://www.teknetelectronics.com/DataSheet/TEKTRONIX/TEKTR_21325410.pdfhttp://www.testequipmentconnection.com/specs/Tektronix_213.PDF

author: c4757p
author_rank: Super Contributor
timestamp: December 02, 2013, 01:41:14 pm
content: I'm probably just too much of a Tek fanboy, but damn, I want that cute little scope!

author: dr.diesel
author_rank: Super Contributor
timestamp: December 02, 2013, 01:45:22 pm
content: Yeah, I have a raging erection, that Tek is awesome.

author: ludzinc
author_rank: Unknown
timestamp: December 02, 2013, 02:41:03 pm
content: A good read on Litchenberg figures can be found here:http://www.howtospotapsychopath.com/2007/12/03/lichtenbergia/And some videos of them being made - also explains why the figure is captured in a layer.

author: andtfoot
author_rank: Unknown
timestamp: December 02, 2013, 02:53:17 pm
content: Oooohh... do want one of those Lichtenberg thingies...Edit: Which Mike kindly pointed out inthis threadthat you can getfrom here.

author: Bored@Work
author_rank: Super Contributor
timestamp: December 02, 2013, 07:40:37 pm
content: Dave, a quick google on the Tek 213 revealed those can have some battery pack inside that used to leak. Maybe a quick check on yours is in order to limit any potential damage.

author: N2IXK
author_rank: Frequent Contributor
timestamp: December 02, 2013, 07:56:15 pm
content: According to the TekWiki, the 213 portable scope was first introduced in 1975.http://w140.com/tekwiki/wiki/213Not a lot of people had digital multimeters back then, so this scope must have been a real piece of geek porn in its day...

author: Nilres
author_rank: Contributor
timestamp: December 02, 2013, 08:28:43 pm
content: Isn't it still geek porn?I love it!

author: edpalmer42
author_rank: Super Contributor
timestamp: December 02, 2013, 09:01:23 pm
content: I used to work for a telco. We had one of the Tek miniscopes in our testroom. I think it was Model 214 - dual trace storage, 500 KHz bandwidth. Very cute!Here's some info on the family:http://w140.com/tekwiki/wiki/Main_Page#200_SeriesEd

author: Jon86
author_rank: Frequent Contributor
timestamp: December 02, 2013, 09:05:52 pm
content: That joke about the queen made me laugh more than I should have

author: joaoc
author_rank: Newbie
timestamp: December 02, 2013, 09:12:24 pm
content: This video shows how to do some pattern (in the end)

author: dewhite2485
author_rank: Newbie
timestamp: December 02, 2013, 10:59:41 pm
content: This is Derek the one who sent you the scope, Im glad you liked it so much! When I got it on ebay the seller had it advertised as untested/non working, lucky for me when I got it everything worked like a charm. Some one has modified it slightly, the BNC connector on the back is not original to the design but seems to work. It didnt have the internal battery when I got it, but should be easy enough to replace if you wanted to use it cordless. Ive had the covers off it before so I know what it looks like inside, but it will be interesting to get a more technical look into its construction and operation.

author: EEVblog
author_rank: Unknown
timestamp: December 02, 2013, 11:21:59 pm
content: Quote from: dewhite2485 on December 02, 2013, 10:59:41 pmThanks Derek, I think this teardown will be popular!

author: Chipguy
author_rank: Unknown
timestamp: December 02, 2013, 11:23:15 pm
content: Told ya, no text

author: dr.diesel
author_rank: Super Contributor
timestamp: December 02, 2013, 11:28:40 pm
content: Quote from: EEVblog on December 02, 2013, 11:21:59 pmTomorrow is Tuesday

author: synapsis
author_rank: Regular Contributor
timestamp: December 03, 2013, 12:10:29 am
content: That scope is awesome! It's the numerical readout that made me want one. Nixie tubes are *so* last year. (Decade?)

author: N2IXK
author_rank: Frequent Contributor
timestamp: December 03, 2013, 01:52:24 am
content: Would really like Dave to tear into the character generator circuitry. I assume it is some kind of vector system, not raster scanned. I agree that the CRT readout has it all over Nixies for sheer coolness. You can get CRT clocks as a kit nowadays:http://oscilloclock.com/http://www.cathodecorner.com/sc200c.htmlFor anyone who is curious about the guts of the Tek 213 and can't wait for Dave's teardown, check this out:

author: Len
author_rank: Frequent Contributor
timestamp: December 03, 2013, 02:37:05 am
content: Quote from: N2IXK on December 03, 2013, 01:52:24 amThe char gen is a single chip with 4-bit binary input and x, y, z vector output.Schematics for the Tektronix 213 are here:http://w140.com/tekwiki/wiki/213

author: fpliuzzi
author_rank: Regular Contributor
timestamp: December 03, 2013, 03:10:24 am
content: Dave,If you're interested in some info about that unusual CRT contained in the Sinclair portable flat TV, the "AndyDaviesByTheSea" channel on youtube has a video where the gentleman describes the part he played in the development of that CRT.The video is "I little bit about my work and Sinclair's flat TV". The Sinclair part starts at the 6:18 point.Regards

author: Zad
author_rank: Super Contributor
timestamp: December 03, 2013, 04:37:29 am
content: Rick Dickinson, the fella who did the industrial design, has some photos of his work on the Sinclair TV on his Flickr page:http://www.flickr.com/photos/9574086@N02/sets/72157601627816164/I got a faulty one from a ham radio rally in the early 1990s and played around with it. The innards are pretty simple, with almost all the work done on one chip. The real interest is in the CRT design, as I'm sure people will see!

author: rr100
author_rank: Frequent Contributor
timestamp: December 03, 2013, 05:52:58 am
content: Quote from: dr.diesel on December 02, 2013, 01:45:22 pmIf it was any longer I would've pissed myself. Awesome stuff!1975 ... and true RMS to boot.BRB, nature calls :-)

author: amyk
author_rank: Super Contributor
timestamp: December 03, 2013, 12:05:08 pm
content: Quote from: N2IXK on December 03, 2013, 01:52:24 amThis reminded me of an article I read quite some time ago about using completely analog means to generate characters for a vector CRT, if I remember correctly it was a PDF scan of something from the 50s-60s era. Anyone know what I'm talking about?

author: tjw
author_rank: Contributor
timestamp: December 03, 2013, 12:17:38 pm
content: Hi,GK mentioned this in his home brew analog computer thread, specifically :https://www.eevblog.com/forum/projects/home-brew-analog-computer-system/165/GK links tohttp://www.nixiebunny.com/crtgen/crtgen.htmlabout half way down page 12 of the thread.Regards, TJW.

author: 84GKSIG
author_rank: Regular Contributor
timestamp: December 03, 2013, 12:53:47 pm
content: that little scope is just beautiful! i need one just like it! now!

author: Balaur
author_rank: Unknown
timestamp: December 03, 2013, 03:10:56 pm
content: Quote from: wilfred on December 03, 2013, 01:12:18 pmIIRC, the TV wasn't working, as the main IC was missing (as described in the message accompanying the TV).

author: Stonent
author_rank: Super Contributor
timestamp: December 03, 2013, 08:55:47 pm
content: Quote from: rr100 on December 03, 2013, 05:52:58 amIf symptoms appear for more than 4 hours call your doctor. I never understood those warnings. There's a lot less embarrassing ways to fix the problem than calling the doctor.

author: Scott
author_rank: Newbie
timestamp: December 03, 2013, 11:18:34 pm
content: I've got four of the 200 series Tek scopes (214, 221 storage, and two 213 DMMs). I'll give away my secret: buy the ones on eBay that are not working at all. Usually the only thing wrong is the NiCd battery pack. If the battery pack is shot, the units often wont even run on AC power. Also, don't power the unit from AC power unless an battery pack is installed.They are great little scopes. I was able to fit three scopes in my carry on luggage for Maker Faire last year!

author: synapsis
author_rank: Regular Contributor
timestamp: December 03, 2013, 11:31:31 pm
content: But now that Dave's had one on his channel, the price of the scopes will go through the roof!

author: Stonent
author_rank: Super Contributor
timestamp: December 04, 2013, 03:34:41 am
content: Quote from: synapsis on December 03, 2013, 11:31:31 pmBonus if someone can figure out how to build a small scope board that connects to the back of a Sinclair TV!

author: Zad
author_rank: Super Contributor
timestamp: December 04, 2013, 03:48:52 am
content: You could probably run a (functional) Sinclair TV quite easily off the Raspberry Pi composite video output. Someone has to try that!

author: amyk
author_rank: Super Contributor
timestamp: December 04, 2013, 06:31:48 am
content: Quote from: tjw on December 03, 2013, 12:17:38 pmThat's the one!I was able to easily find the PDF version after seeing that:http://www.thecorememory.com/GenCharforCRR.pdf

author: Stonent
author_rank: Super Contributor
timestamp: December 04, 2013, 07:21:36 am
content: Quote from: Zad on December 04, 2013, 03:48:52 amYou'd need an RF Modulator to convert the Comp to RF signals.

author: Zad
author_rank: Super Contributor
timestamp: December 05, 2013, 03:29:39 am
content: It depends on what goes on inside the chip. It has a composite video output pin that you should be able to tap onto to inject the Rasp Pi's analogue output. It may be that the chip samples the signal before this point to derive synch etc.

author: N2IXK
author_rank: Frequent Contributor
timestamp: December 05, 2013, 03:50:21 am
content: There is a block diagram of the ZN401E-2 chip here:http://www.thevalvepage.com/tv/sinclair/ftv1/announc.htmLooks like the composite video could be injected right at the detector output, feeding both the CRT drive and the sync separator.Does anyone have a copy of the actual Ferranti datasheet for the chip, or was this a proprietary design just for Sinclair? A really interesting design, using what appears to be a synchronous detector for the audio, and a PLL with dual DACs to produce the deflection waveforms.

author: EEVblog
author_rank: Unknown
timestamp: December 05, 2013, 04:09:24 am
content: Quote from: N2IXK on December 05, 2013, 03:50:21 amThe chip is needed to generate all the timing though. Could be done manually, but messy.

author: N2IXK
author_rank: Frequent Contributor
timestamp: December 05, 2013, 04:20:15 am
content: Yes, without the magic chip, getting anything on the screen would be a LOT of work. Almost the entire signal processing system (video, audio, sync, and sweep generation) is contained in that little guy...

author: JoannaK
author_rank: Frequent Contributor
timestamp: December 05, 2013, 04:36:55 am
content: Sounds a lot like Fpga.project.. or Propeller.

author: amyk
author_rank: Super Contributor
timestamp: December 05, 2013, 06:40:08 am
content: I remember seeing online a schematic + datasheet for a Chinese-made portable CRT TV (recently) that had everything on one chip... but can't find it now.Edit: found it!http://shiximm.com/baogaofanwen/261729.htmlhttp://datasheet.seekic.com/PdfFile/D29/D2915.pdf

author: SeanB
author_rank: Super Contributor
timestamp: December 05, 2013, 07:25:30 pm
content: n the late 1980's Maplin was selling off the boards as spare parts, possibly working but without the CRT, main chip and tuner. Probably ones that were DOA from the assembly line, where they would pull the most expensive items ( Tuner, CRT and the ASIC) from them to reuse. Probably the main reason the ASIC was in a socket is that they were heat sensitive, and were the single highest cost item in the set, probably costing more than the CRT.I watched the Andie Davies memories about Sinclair, was very entertaining on how difficult those were to make.As to the battery packs, they were a part of instant film packs, used to drive the camera motors, focussing system and the flash circuitry. Pretty impressive for the first mass produced pouch cells, they were nice to use in projects as discards from camera packs, still having a lot of power left in them after the 120 shots from the film unit. Only issue was connecting to the aluminium foil tabs as they were not solderable. I generally used a crocodile clip or paper clip as a contact with a piece of magic tape as a cover for the clip.

author: peter.mitchell
author_rank: Super Contributor
timestamp: December 10, 2013, 03:52:47 pm
content: Quote from: TheSolderShack on December 10, 2013, 01:23:17 pmMy experience with UK-> Aus any time of year is very quick. I'd say it would take a week, maybe 2, tops.

author: beounet
author_rank: Newbie
timestamp: December 13, 2013, 09:07:15 pm
content: Hey Dave!! About the camera zoom issue, why don't you make a foot-pedal zoom switch?

author: delmadord
author_rank: Regular Contributor
timestamp: December 27, 2013, 08:36:19 pm
content: Just a quick GIF

author: delmadord
author_rank: Regular Contributor
timestamp: January 08, 2014, 10:36:44 am
content: and just one more pic

author: wilheldp
author_rank: Regular Contributor
timestamp: January 08, 2014, 06:33:23 pm
content: As crazy/stupid as some people are with body modification, it would surprise me if a craze started where people were trying to get struck by lightning to get a "cool" Lichtenberg figure "tattoo."

author: SeanB
author_rank: Super Contributor
timestamp: January 08, 2014, 06:56:07 pm
content: At least that would be self limiting, most do not survive the experience.

author: IanJ
author_rank: Unknown
timestamp: January 08, 2014, 07:17:14 pm
content: Quote from: wilheldp on January 08, 2014, 06:33:23 pmIf Doc Brown can do it (albeit unintentionally) then surely Dave will give it a go........Ian.