EEVblog #711 - Mailbag - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: February 03, 2015, 12:48:57 pm
content: Mailbag time.SPOILERS:Making of the Atomic Bomb:http://amzn.to/1CUMscYThe Bruces Monty Python Sketch:Ideal diode (synchronous rectifier) datasheet:http://www.linear.com/product/LT4320Car ECU teardownPAL to RGBS converter teardownPump controller teardownMeet Edison Educational Robot:http://meetedison.com/Casio FX790P scientific calculator pocket computer:http://www.rskey.org/CMS/index.php/7?manufacturer=Casio&model=FX-790PPAL/NTSC decoder:http://pdf.datasheetcatalog.com/datasheet/philips/TDA3566A.pdfDigikey ChipKIT WF32https://www.digilentinc.com/Products/Detail.cfm?NavPath=2,892,1193&Prod=CHIPKIT-WF32Basys 3 Artix-7 FPGA Demo Boardhttps://www.digilentinc.com/Products/Detail.cfm?NavPath=2,400,1288&Prod=BASYS3

author: R_Gtx
author_rank: Regular Contributor
timestamp: February 03, 2015, 02:04:29 pm
content: I don't know what IGBTs or MOSFETs are restricted, but you could attempt purchasing a krytron through ebay.

author: SL4P
author_rank: Super Contributor
timestamp: February 03, 2015, 03:19:38 pm
content: When I saw the contents of this week's video - I had to do a double take - and looked back in my mind to find a very similar book written 45 YEARS ago - which I vividly remember as one of the most interesting accounts of the A-Bomb development...The History Of The Atomic Bomb, by Michael BlowFrom the reviews, it still seems to hold its place in many libraries!http://www.goodreads.com/book/show/11317555-the-history-of-the-atomic-bombhttp://www.amazon.ca/History-Atomic-Bomb-Michael-Blow/dp/0060201274

author: FHR
author_rank: Contributor
timestamp: February 03, 2015, 03:38:17 pm
content: Hi Dave,Regarding the motherboard you will need for those 2 new Xeons, I recommend you the Supermicro X9DAi boardhttp://www.supermicro.nl/products/motherboard/Xeon/C600/X9DAi.cfm.It has all the features you need - It supports DDR3 non-ECC RAMs, has a sound card, has SATA III/6Gbps, has 3 16x PCI-E slots.Your power supply is enough to power this thing, you do not need a new one. However, you need a reduction from Molex to 4/8pin CPU power connector. Those boards require 2 4/8pin CPU power connectors, your power supply only has one (like 99% of desktop power supplies). Also check that you can fit the board into your chassis.TO-BUY list if you choose this board:Motherboard (obviously)Molex to 4/8 pin CPU (something like thishttp://www.directron.com/ad202.html)Possibly a new chassis. Depends if you can fit the EATX board into your chassis.CPU Coolers

author: Porto
author_rank: Contributor
timestamp: February 03, 2015, 04:29:50 pm
content: Had this Casio FX790P programmable computer/calculator in school more than 20 years ago, bought from Tandy.Programmed a few little but quite neat programs with it in Basic.Also own the cute little thermal printer that came with the deal.Unfortunately it broke down on me some years after (flatcable between the two halves is VERY sensitive) and is now lying in multiple pieces waiting for a, long forgotten, repair.

author: gardner
author_rank: Regular Contributor
timestamp: February 03, 2015, 05:23:06 pm
content: One of my favourite reads on nuclear weapons history is this:http://blog.nuclearsecrecy.com/QuoteA really interesting perspective from a talented researcher.

author: Richard Crowley
author_rank: Super Contributor
timestamp: February 03, 2015, 05:26:16 pm
content: Re: Vibration resistance of SIP components in the Subaru ECU.I suspect that the module was made to mount vertically (like on the firewall, etc.) and with the two big tabs on either side, so the giant connector is at the bottom.In this orientation, note that all the SIP components/modules are vertical, so the majority of vibration will be vertical also (from bumpy roads, etc.)I suspect this wasn't by accident that they are all vertical. Maybe even those can radial electrolytics have their pins arranged in that orientation as well.

author: German_EE
author_rank: Super Contributor
timestamp: February 03, 2015, 07:31:48 pm
content: Dave, as you like nuclear history the following YouTube channel may be of interest.https://www.youtube.com/user/atomcentral

author: hikariuk
author_rank: Unknown
timestamp: February 03, 2015, 08:03:30 pm
content: O Level sounds distinctly like a vestige of British colonial rule; we used to have O Levels (at 16) and A Levels (at 18).

author: rsjsouza
author_rank: Super Contributor
timestamp: February 03, 2015, 08:11:27 pm
content: Dave, as I commented in the past Amp Hour:Quote from: TheAmpHour comment section

author: max666
author_rank: Frequent Contributor
timestamp: February 03, 2015, 09:20:12 pm
content: I don't understand why you would call someone "not aproperpcb designer", because of old school square routing, Dave. :/

author: senso
author_rank: Frequent Contributor
timestamp: February 03, 2015, 09:22:30 pm
content: It might even be a software limitation, I have redrawn pcb's for Bosch made in the 80's that where all square routing and they demanded that I kept the square routing, low speed signals, what's the problem with not having 45º corners?All the electrons will crash in the turn?

author: max_torque
author_rank: Super Contributor
timestamp: February 03, 2015, 09:44:49 pm
content: Quote from: Richard Crowley on February 03, 2015, 05:26:16 pmIt's also worth noting that engine controllers from this era, were mounted in the vehicles main cabin, rather than underbonnet, and hence have a much lower requirement for environmental sealing and vibration resistance. (being bolted to a ton of body shell automatically limits the peak operating g the unit can undergo!) Modern units are now underbonnet or even engine mounted to reduce the wiring loom cost and improve the engine integration aspect where one engine family is used across multiple platforms.Modern devices are entirely SMC and use drivers in packages like SOIC-PowerSO with a large soldered tag underneath for heat sinking and mechanical security:For example here is an early 2000's EDC17 Bosch ecu:

author: EEVblog
author_rank: Unknown
timestamp: February 03, 2015, 09:51:54 pm
content: Quote from: FHR on February 03, 2015, 03:38:17 pmSomeone has kindly donated one of these boards ( I can pick):http://www.supermicro.com/products/motherboard/Xeon/C600/X9DRL-EF.cfmhttp://www.supermicro.com/products/motherboard/Xeon/C600/X9DAE.cfmhttp://www.supermicro.com.tw/index.cfmhttp://www.intel.com/content/www/us/en/motherboards/server-motherboards/server-board-s2600cp.html

author: EEVblog
author_rank: Unknown
timestamp: February 03, 2015, 09:53:47 pm
content: Quote from: max_torque on February 03, 2015, 09:44:49 pmYes, it wouldn't be about peak G's, it would be about hitting resonant frequencies of free standing packages from broadband vibration.I've seen free standing TO-220 packages vibrate clean off from just wheeling up and down a production floor for a few weeks on a metal trolley.

author: Richard Crowley
author_rank: Super Contributor
timestamp: February 03, 2015, 10:42:21 pm
content: Quote from: EEVblog on February 03, 2015, 09:53:47 pmAnd that TO-220 device is mounted "horizontally" which would make it MORE vulnerable to vertical vibration.The pin pattern was in a triangle, but the leads were formed to that everything above the surface of the PC board was parallel.It would probably be speculative to assume they designed it that way so that the springiness of the leads absorbed the vibration from the mass of the package.....I was also very surprised it wasn't conformally coated. But if it was designed to go inside the passenger compartment, that might explain it.

author: necessaryevil
author_rank: Regular Contributor
timestamp: February 03, 2015, 11:08:26 pm
content: Quote from: Porto on February 03, 2015, 04:29:50 pmGeI was the one who sent it in. It used to belong to my dad, he wanted to throw it away but I told him I knew somebody who collects calculators. I showed him the video; he was convinced that his one was a bit different than the one in the video - until I told him I send Dave the calculator.The calculator was bought in Singapore by my uncle who was on his way to Australia (or came back). The calculator has been all over the world! By the way, I know that the Australian import/export rules are strict, that is why I didn't include the batteries, just to be sure.And about the rectifier: yes, each pair of mosfet rectifiers face the same way because I intended use of a heat sink. If a heat sink is actually necessary depends on the current drawn and on the mosfets. The major source of heat will be originate from conduction losses, so the Rds(on) is the most important parameter. Just if someone wants to know!

author: synapsis
author_rank: Regular Contributor
timestamp: February 03, 2015, 11:44:40 pm
content: I had to pause the video and order the Atomic Bomb book.Another good book if you're also interested in photography is "How to Photograph an Atomic Bomb."http://www.unitednuclear.com/index.php?main_page=product_info&cPath=29_58&products_id=442I picked mine up at the Titan Missile Museum here in Tucson. Great place to visit if you're interested in that kinda stuff. You go down into the silo, the control room, the support areas, etc...

author: mattinx
author_rank: Newbie
timestamp: February 04, 2015, 12:27:41 am
content: Quote from: FHR on February 03, 2015, 03:38:17 pmI'll second that SuperMicro recommendation - we build quite a few systems round that platform, theX9DR3-LN4Fis our preferred board, but we're typically looking at it from an IO standpoint.Trap for young players - remember to check what warranty you have on the board - the 3 year warranty is an optional extra.

author: Dongulus
author_rank: Regular Contributor
timestamp: February 04, 2015, 02:55:14 am
content: I was hoping that the package from Digilent had a Zybo instead of the Basys 3. I've been wanting to play around with the Zynq 7000 SoC and I've been eyeing the Zybo because it seems to be the cheapest dev board for the Zynq. I've also been looking at the Altera Cyclone V SoC development board from Terasic which seems to be a bit more bang for the buck.

author: EEVblog
author_rank: Unknown
timestamp: February 04, 2015, 03:03:55 am
content: Quote from: wilfred on February 04, 2015, 12:05:02 amIf you just want to learn FPGA's, makes no difference at all.

author: urbis
author_rank: Unknown
timestamp: February 04, 2015, 08:44:12 am
content: I see my item in the background, at least I know it arrived safely! O0

author: jancumps
author_rank: Unknown
timestamp: February 04, 2015, 09:48:09 am
content: Quote from: EEVblog on February 04, 2015, 03:03:55 amThe only difference for the Digilent boards is that the new one is supported by their new IDE.The ones with Spartan 6 and older FPGAs are not supported.You need the Xilinx ISE development environment for them.It's a good and capable IDE, but active development has ended.it's still supported by Xilinx.

author: Fungus
author_rank: Super Contributor
timestamp: February 04, 2015, 03:09:32 pm
content: Quote from: EEVblog on February 03, 2015, 09:51:54 pmI was going to suggest a cheaper way of getting more cores for video rendering than using Xeons but if people are donating the CPUsandmotherboards then I guess there's not much point.

author: Monkeh
author_rank: Super Contributor
timestamp: February 04, 2015, 06:06:29 pm
content: Quote from: EEVblog on February 03, 2015, 09:51:54 pmThe Intel one supports significantly superior processors, but may not fit a normal case.

author: Richard Crowley
author_rank: Super Contributor
timestamp: February 04, 2015, 06:55:07 pm
content: Quote from: Monkeh on February 04, 2015, 06:06:29 pmYeah, that Intel board is clearly a SERVER board and is substantially bigger than any of the traditional client MB form-factors.What happened to those servers Dave got out of the dumpster? Are they already gone?

author: Monkeh
author_rank: Super Contributor
timestamp: February 04, 2015, 07:05:13 pm
content: Quote from: Richard Crowley on February 04, 2015, 06:55:07 pmSo are the two Supermicro boards. One of them is E-ATX, which has the same dimensions as the Intel board.

author: max_torque
author_rank: Super Contributor
timestamp: February 04, 2015, 11:28:57 pm
content: Quote from: EEVblog on February 03, 2015, 09:53:47 pmBut that is exactly the point, there isn't any! (well very little) because the mass of the body shell damps it so effectively. Chances are, those SIL leaded components have resonant frequencies in the hundreds of Hz range. Now calculate the power required to say vibrate even 20kg of steel body shell at just 100Hz. It's massive!Ok, mistakes have been made, people have bolted control units to flat panels that pant or suffer a critical oscillation from drivetrain driven resonance, but generally speaking it doesn't happen as modern car are so well designed/tested (not to mention the NVH aspect of having parts of your bodyinwhite vibrate at 100hz). The primary ride frequency of a typical passenger car is in the order of 1 or 2Hz, and most of the accoustic noise is extremely low amplitude at say >1000Hz, that noise won't even make it through the pcb, let alone snap components off it!(In fact, the only time i can actually remember an issue with a control unit failing was on a rally car, where the control unit had been mounted on rubber, vibration absorbing "bobins" in a misguided attempt to reduce transmitted vibrations. What actually happened is that those rubber mounts, in conjunction with the mass of the control unit forms a critically tuned spring/mass oscillator at around 10Hz, which for a competition car IS in the normal ride frequency region. As a result, there were some failures of some large through hole capacitors on a few units. When we removed the rubber compliance, bolted the control unit directly to the bodyinwhite, all was well! ;-)

author: FHR
author_rank: Contributor
timestamp: February 05, 2015, 03:24:02 pm
content: Quote from: EEVblog on February 03, 2015, 09:51:54 pmThe X9DAE is the one to pick. You need a workstation board, not a server one. These other boards you mentioned don't even have a sound card.

author: Monkeh
author_rank: Super Contributor
timestamp: February 05, 2015, 04:36:30 pm
content: Quote from: FHR on February 05, 2015, 03:24:02 pmYou can get proper soundcards instead of onboard crap, you know. Lack of onboard audio is not exactly a dealbreaker on a board with six PCI-E slots.

author: FHR
author_rank: Contributor
timestamp: February 05, 2015, 04:46:02 pm
content: Quote from: Monkeh on February 05, 2015, 04:36:30 pmBut does he really need to? He said he will use it as a rendering and editing machine. Not his home machine. Also, for most (normal) people are onboard sound cards ok. If he would play games on it - yes, buy a sound card. Use it for listening to music with headphone priced 300$? Yes, buy a sound card. For video editing it's perfectly fine.Besides as I said, those other boards are for SERVER use, not for WORKSTATION use. There are more things, that server boards lack besides sound card. Support for SLI, sometimes Fan regulation. Server boards also have a lot less desktop-use connectivity options. I'm talking about USB 3.0, Firewire, etc.

author: Monkeh
author_rank: Super Contributor
timestamp: February 05, 2015, 04:55:26 pm
content: Quote from: FHR on February 05, 2015, 04:46:02 pmYou don't need a soundcard for playing games!QuoteSLI is irrelevant. Fan regulation is a potential but unlikely concern. USB 3 is easily added, Firewire is rarely provided anymore anyway. All acceptable losses to get Haswell instead of Ivy Bridge!E: Hang on, that Intel board said v3 compatibility yesterday, and v2 today. Okay, in that case you're right, the X9DAE is the one to pick.

author: FHR
author_rank: Contributor
timestamp: February 05, 2015, 05:01:48 pm
content: Quote from: Monkeh on February 05, 2015, 04:55:26 pmThe CPUs (SR1AM; E5-2630v2) are Ivy Bridge-EP's anyway. v3 also means DDR4 RAM => he would have to buy a new RAM. I'm not sure the CPU's would be compatible anyway, even if they are the same socket. Intel likes to mess with those things that they are not always backwards/forwards compatible.

author: Monkeh
author_rank: Super Contributor
timestamp: February 05, 2015, 05:03:06 pm
content: Quote from: FHR on February 05, 2015, 05:01:48 pmI was not aware CPUs were already acquired.

author: Fungus
author_rank: Super Contributor
timestamp: February 05, 2015, 05:28:39 pm
content: Quote from: Monkeh on February 05, 2015, 05:03:06 pmHint: They're in the video...

author: Monkeh
author_rank: Super Contributor
timestamp: February 05, 2015, 05:30:31 pm
content: Quote from: Fungus on February 05, 2015, 05:28:39 pmAnd not mentioned in any description. Nothing in the description of the video interested me, so I haven't used any of my free time to watch it as of yet. It's a shocking thing, I know, not spending every minute of my life keeping up to date with other people's lives..

author: Fungus
author_rank: Super Contributor
timestamp: February 05, 2015, 05:52:40 pm
content: Quote from: Monkeh on February 05, 2015, 05:30:31 pmIs there a description? The things above the video are only links to items in the video so you can follow up on them.Would you have watched it if he'd put a link to Intel's Xeon CPU page?Intel Xeon CPUs:http://www.intel.com/Xeons...Quote from: Monkeh on February 05, 2015, 05:30:31 pmBut youdohave time to comment on videos that you haven't even watched...?

author: Monkeh
author_rank: Super Contributor
timestamp: February 05, 2015, 05:54:27 pm
content: Quote from: Fungus on February 05, 2015, 05:52:40 pmI'd have known there was something about CPUs in it..QuoteI haven't made any comments about the video, now have I?This takes seconds to type, the video requires 40 minutes of my attention..

author: hikariuk
author_rank: Unknown
timestamp: February 05, 2015, 07:04:03 pm
content: Quote from: Monkeh on February 05, 2015, 04:36:30 pmTangenting wildly, however: onboard sound cards are fine for pretty much everyone. Anyone who actually needs to give a shit about audio probably just uses an external DAC anyway.

author: Fungus
author_rank: Super Contributor
timestamp: February 05, 2015, 07:41:20 pm
content: Quote from: hikariuk on February 05, 2015, 07:04:03 pmYep.And you can get a good one for about $12 on eBay so it's not even worth quibbling over, just get one...(eBay search term: "pcm2704")

author: RupertGo
author_rank: Regular Contributor
timestamp: February 06, 2015, 11:26:13 am
content: And you can get a no-name audio dongle for a couple of quid. I have one here that I bought for random amateur radio faffery, now using it as my main audio ouput device on the microsever that happens to be my current work PC. I've done some quite intensive listening/input tests on it through Sennheisers that cost more than the server, comparing it to a variety of other sources/inputs, and damned if I can tell the difference even on 'audiophiie' material and a decent mic I use for broadcast work.I take a particularly perverse delight in playing Neil Young through it.(as part of this completely unscientific testing, I bunged the scope across the output of a £20 TA2020-based amp. My lord, but that was shocking - enough RF to light up the ionosphere. Still sounded excellent...)

author: Fungus
author_rank: Super Contributor
timestamp: February 06, 2015, 11:57:45 am
content: Going the other way around... anybody know of a decent, cheapo USB device for microphone input?(One with manual adjustment of the input level, obviously...)

author: Richard Crowley
author_rank: Super Contributor
timestamp: February 06, 2015, 12:27:38 pm
content: Quote from: Fungus on February 06, 2015, 11:57:45 amWhat does "cheapo" mean? Can you put some numbers to that?Do you mean a "pro" XLR microphone? Or a 3.5mm consumer job?If XLR, do you need phantom power for the microphone (e.g. a condenser mic)?Or are you talking about a dynamic mic or a condenser mic with its own battery?If you are talking about 3.5mm input, does the mic require "plug-in power"?Or is it self-powered?When you say "manual adjustment" do you mean a physical knob?Or do you mean a software adjustment?Do you need low-latency monitoring (as for multi-tracking musical performance)?Or is this just for basic and simple one-off recording?Is this for portable use out in the field? Or a fixed installation at home/office?

author: FHR
author_rank: Contributor
timestamp: February 06, 2015, 01:37:42 pm
content: Quote from: Fungus on February 06, 2015, 11:57:45 amI use a bigger brother of this, the Q1202USB one and it is absolutely great.

author: Fungus
author_rank: Super Contributor
timestamp: February 06, 2015, 05:04:16 pm
content: Quote from: Richard Crowley on February 06, 2015, 12:27:38 pmIf I can get a decent $12 DAC then I don't see why a mic input device good enough for voice recording should cost much more than that.Quote from: Richard Crowley on February 06, 2015, 12:27:38 pm:-)This:http://www.audio-technica.com/cms/wired_mics/9c6eca17168eef6f/Battery powered condenser mike with 3.5mm jack plug.Quote from: Richard Crowley on February 06, 2015, 12:27:38 pmThis is for PC screen-recording with voice-over.(I can connect it to the camera if I'm out somewhere recording video....)

author: ornea
author_rank: Unknown
timestamp: February 06, 2015, 05:55:37 pm
content: Curious if your studio lights were messing with Edison's collision avoidance sensors.

author: Richard Crowley
author_rank: Super Contributor
timestamp: February 06, 2015, 06:00:36 pm
content: You can probably plug that microphone directly into your computer. Why do you need an external interface>

author: Fungus
author_rank: Super Contributor
timestamp: February 06, 2015, 06:13:17 pm
content: I've been digging around eBay and there doesn't seem to be much choice. I guess there isn't as much demand as there is for audio DACs.This looks reasonably close to what I'm after:http://www.ebay.com/itm/360959008656It's based on this chip:http://www.cmedia.com.tw/productsdetail/page-p/c1serno-25/c2serno-26/pserno-7.htmlIt actually has a datasheet!$7 seems a bit cheap but really it's just an IC embedded in a cable so how much should it be?

author: Fungus
author_rank: Super Contributor
timestamp: February 06, 2015, 06:14:17 pm
content: Quote from: Richard Crowley on February 06, 2015, 06:00:36 pmFor the same reason I don't plug my headphones directly into the computer - the sound is as noisy as hell compared to my external DAC.

author: Richard Crowley
author_rank: Super Contributor
timestamp: February 06, 2015, 06:26:43 pm
content: http://www.audio-technica.com/cms/accessories/de806038b48c13d7/

author: Fungus
author_rank: Super Contributor
timestamp: February 06, 2015, 06:52:59 pm
content: I've got one of these external boxes:http://www.ebay.com/itm/221681003044It's USB and has headphone, mic, line in/out, SPDIF, etc. but it's absolute garbage. I can't believe they cost about $90 new. I can actually plug a pair of headphones into it and go around the room finding RF interference hotspots with the buzz it produces. It's really sensitive/directional for that usage scenario but not really what you want in a sound card.It also has an incredibly bright blue LED on it thatflasheswhen it's receiving audio - absolutely useless in a dark roomMaybe I should send it to Dave for a teardown and laugh.(or maybe I could try and get $25 for it on eBay)I swear I'll never buy another Creative Labs product as long as I live. I once bought some of their "THX certified" desktop speakers because all the PC magazines were going crazy giving them gold stars that month. The sound was so bad I actually felt guilty about selling them on eBay the next day in case a musician bought them or something. It doesn't give much confidence in PC magazine audio reviews either.PS: I can put my cheapo PCM2704 DAC right next to the WiFi router and it's completely OK (presumably because it's in a metal case).The PCM2704 also has about 8db more dynamic range than the AD1825 used in that SoundBlaster - winner, winner, chicken dinner!

author: Fungus
author_rank: Super Contributor
timestamp: February 06, 2015, 06:58:32 pm
content: Quote from: Richard Crowley on February 06, 2015, 06:26:43 pmHey, cool!I'm a bit of a fan of Audio Technica (I use their Headphones, etc.)I wonder where I could buy one of those...

author: f4eru
author_rank: Super Contributor
timestamp: February 10, 2015, 12:09:12 am
content: Dave, the glass-piezo delay line is for PAL, coz PAL combines two lines to average out color info ( phase changes, so the error cancels)http://en.wikipedia.org/wiki/PAL#Colour_encodingFor the car ECU, it's really old school and robust.These DIP packages are OK, and the whole thing is properly tested on big shakers, so no worries.I'm much more worried with modern ECUs, which more and more have BGA packages. These ones can fail badly.I've seen relays and caps hot snotted in a body controller (approx 5 million /year produced) the material was carefully chosen for the temp range, the dispensing automatic and the design validated, so it was OK

author: rgammans
author_rank: Newbie
timestamp: February 10, 2015, 09:53:21 pm
content: I wonder if the two mods Dave showed on the PAL decoder where 'end user' mods - rather than manufacturer mods.The R+C between Sync + Green looks like the classic trick to add Sync on Green output to a device which doesn't already have it.I wonder if the CMOS logic was some sort of Sync combiner/separator too. Many monitors of the period could be quite set in their ways about the type of sync they got.