EEVblog #745 - Mailbag - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: May 19, 2015, 01:18:18 am
content: Mailbag time again. Dave opens his mail. What random stuff awaits?Forum:SPOILERS:A vintage Japanese Sharp X68000 home computer from the 1980'sTeardowns of an industrial controller, a LED light controller, ABB industrial switchmode power supply, Casio FX3800P programmable calculator, old Gossen digital multimeter and a German analog meter.Belgian chocolate.Surprise visit by SaganTwo Kickstarter Projects:Femtocow USB912https://www.kickstarter.com/projects/femtocow/usb-912Bluetooth Audio Link (BAL)https://www.kickstarter.com/projects/doayee/bluetooth-audio-linkA solar powered propeller hat and electronics business card:http://shop.asmyldof.com/Multimeter chipset:http://datasheets.maximintegrated.com/en/ds/ICL7136.pdf

author: redshift
author_rank: Contributor
timestamp: May 19, 2015, 01:42:42 am
content: That X68000 could be pretty valuable if it works.Also, are Nestle chocolates popular in Australia? Because the last time I was in New Zealand they were nowhere to be found.Edit: I forgot to mention that you have to press down on that X68000 handle to release it

author: EEVblog
author_rank: Unknown
timestamp: May 19, 2015, 03:44:50 am
content: Quote from: redshift on May 19, 2015, 01:42:42 amYep, shelves are full of them.QuoteDoh!This one doesn't work that great.

author: PaulS
author_rank: Contributor
timestamp: May 19, 2015, 04:04:28 am
content: You missed the perfect opportunity to say "2-minute teardown!" before opening the chocolate.

author: djQUAN
author_rank: Frequent Contributor
timestamp: May 19, 2015, 05:40:56 am
content: Green tea Kitkat. Mmmm. They got various flavoured Kitkats there. Give it a try, it's good

author: Barny
author_rank: Frequent Contributor
timestamp: May 19, 2015, 06:01:30 am
content: A little hint:Video time 36:18 ->Elektrische DatenThats german forelectrical dataAnd below are the technical data for DC (Gleichstrommessung) and AC (Wechselstrommessung).

author: Rasz
author_rank: Super Contributor
timestamp: May 19, 2015, 07:06:54 am
content: mmm that X68000, its a legend. Only computer to receive perfect arcade ports from companies like Konami. Retro gaming nerds must of fainted when you opened that one up

author: forrestc
author_rank: Unknown
timestamp: May 19, 2015, 08:13:14 am
content: A couple of notes about the PLC:(Note: these are semi-informed speculation having used PLC's in this era).The part which daved pulled off which had the EAR and MIC jacks on it is likely just a programming interface. Because of the cost of the programming interface, many plc's had a separate programmer which you would take from device to device. The D25 connector on the programmer is likely for a printer to print the program out. And the EAR and MIC jacks - well that's most likely to save the program to a cassette tape.RY I'm about 99% sure is short for 'Relay'. Oh wait, I just got to that part of the video where Dave figured it out. So I guess that's not much of a revelation.One note about the architecture: The PLC itself has a processor with the eeprom with the actual 6800 code in it. Through some sort of proprietary interface between the programmer (which has a separate CPU which knows how to do the display and all the programming interface stuff) and the internal CPU, you would load the logic program into the RAM chips on the CPU board. That supercap most likely holds enough power to keep the program in the SRAM during power outage. Once the programmer loaded the code into the processor board inside the plc it could be removed and the PLC processor would run the entire show without the programmer needing to be attached.One additional note:On the programmer near the DB25, you'll see a couple of IC's with 75188 and 75189 on them. Those are IC's which do RS-232 to TTL and vice versa (one for each direction).I recognized those chips immediately as I swear those IC's were the bane of my existance in the late 80's.... There was the Motorola MC1488 and MC1489 which I think were first, then other manufacturers came up with their own pin compatible versions which were all numbered differently, except they all seemed to end with '88' or '89'. SN55189, SN75189, etc. The driver needed both +12V and -12V rails, and the receiver only needed +5V.They also were not very robust. On longer serial links (or sometimes even on a short one), those parts would die. Or for a short, or because they felt like it was time to retire. Who knows. (I think the phase of the moon had something to do with it too).As a result, it wasn't all that uncommon to see just those two parts socketed on a completely socketed board. Those were two chips you always kept on hand - and if one which wasn't socketed failed, you sure put a socket in place instead of just replacing the IC. This board obviously has been spared.

author: RobHeffo
author_rank: Newbie
timestamp: May 19, 2015, 09:36:04 am
content: Hey Dave!I think that very thick white block on the very chunky heatsink in the ABB power supply might actually be a Peltier TEC Module for actively cooling the component.

author: vlad777
author_rank: Frequent Contributor
timestamp: May 19, 2015, 09:53:09 am
content: I will never part from this. Dave. Never!Don't expect it in the mailbox.

author: Fungus
author_rank: Super Contributor
timestamp: May 19, 2015, 10:31:19 am
content: "Duck" is a brand of duct tape:http://www.duckbrand.com/products/repair-project-duck-tape/original-duck-tape-regThat's where the confusion comes from.("Professional Strength" ... oooh!)

author: bktemp
author_rank: Super Contributor
timestamp: May 19, 2015, 11:52:32 am
content: Quote from: RobHeffo on May 19, 2015, 09:36:04 amI have never seen a TEC in a power supply.It is more likely aluminium oxide. Aluminium oxide is a good thermal and electrical insulator used here instead of the more common silica or mica pads because of the better electrical insulation.

author: c4757p
author_rank: Super Contributor
timestamp: May 19, 2015, 12:04:54 pm
content: Duct/duck tape: have a look over the first few paragraphs here:http://en.wikipedia.org/wiki/Duct_tape

author: djQUAN
author_rank: Frequent Contributor
timestamp: May 19, 2015, 12:28:41 pm
content: Quote from: bktemp on May 19, 2015, 11:52:32 amI agree. It is probably the main switching device and the spacer helps reduce capacitive coupling between the device and the thick heat spreader for lower EMI.

author: nathanpc
author_rank: Unknown
timestamp: May 19, 2015, 12:32:43 pm
content: Did anyone else notice those plastic standoffs on the TO-220 legs?

author: djQUAN
author_rank: Frequent Contributor
timestamp: May 19, 2015, 12:37:40 pm
content: Those look like ferrite beads. I see them most of the time on SMPS output rectifiers to smooth out the current spikes when the diodes turn on or off.

author: nitro2k01
author_rank: Frequent Contributor
timestamp: May 19, 2015, 12:54:18 pm
content: So, a Swedish package, wrapped in duct tape, containing a duck with a capacitor in it, put in a Swiss chocolate box. But that's not all, the package also contained a power supply by Swiss-Swedish company...

author: SL4P
author_rank: Super Contributor
timestamp: May 19, 2015, 01:10:56 pm
content: Quote from: nitro2k01 on May 19, 2015, 12:54:18 pmBut does it quack?(If it looks like a duck, and sounds like a duck... then it might not be a chicken.)

author: VK3DRB
author_rank: Super Contributor
timestamp: May 19, 2015, 01:40:13 pm
content: Wow. I thought I was the only nerd/dag/dork/geek who had fun computing 69 factorial on a calculator to test its speed.I had a 1983 Casio LCD calculator (advanced for its time) that would take about 5 seconds to compute it.I tried it with my trusty RealCalc app on my Samgung S3 mobile telephone. It was of course instant. In fact RealCalc computed up to 449 factorial, and the instant result was 3.85193051803 x 10997, which is almost of big as the US net debt...http://www.usdebtclock.org/

author: Fungus
author_rank: Super Contributor
timestamp: May 19, 2015, 01:47:19 pm
content: Quote from: VK3DRB on May 19, 2015, 01:40:13 pmBeen there. Done that.I'm surprised they never cheated and stored that result in ROM to fool the 'benchmarkers'.

author: Muttley Snickers
author_rank: Unknown
timestamp: May 19, 2015, 01:57:47 pm
content: Quote from: nitro2k01 on May 19, 2015, 12:54:18 pmThe sender might be slightly annoyed that Dave used the wrong knife...Muttley

author: vlad777
author_rank: Frequent Contributor
timestamp: May 19, 2015, 03:27:33 pm
content: " US net debt...http://www.usdebtclock.org/"WOW. It's good that it takes exponential to get to those high decimal digits...

author: nitro2k01
author_rank: Frequent Contributor
timestamp: May 19, 2015, 04:50:45 pm
content: Quote from: SL4P on May 19, 2015, 01:10:56 pmAlso, if it smells like chicken and screams like a pig, it's probably holding the soldering iron wrong way around.

author: m100
author_rank: Regular Contributor
timestamp: May 19, 2015, 05:28:57 pm
content: At around 21 mins in did I really hear Dave call the Netherlands a Nordic country?

author: SeanB
author_rank: Super Contributor
timestamp: May 19, 2015, 06:20:31 pm
content: I use a Casio FX602P, had it since high school. Only had to change the batteries around 3 times, as it is so frugal on power. I used to have the add on printer/cassette interface, but that died a long time ago. It could also be used to play music using the serial data output.

author: Asmyldof
author_rank: Regular Contributor
timestamp: May 19, 2015, 06:30:42 pm
content: Quote from: m100 on May 19, 2015, 05:28:57 pmWell, we're only removed from them by some water and/or another country. So. Apples and somewhat un-apple-y oranges I'd say.Hi there! Any questions about the candy welcome ;-)Robert!Forgot to add this to the note, Dave, the closest approximation to the pronunciation- that I can think of - is: "vaan Lay-when", Written as "van Leeuwen", which means as much as "of Lions")EDIT: Also super stoked it all made it in there.AND: The Solar cap did work before shipment using my cheap off-brand Chinese 7W white LED torch focussed entirely on it. Solars do prefer a "hotter flavour of light" (e.g. 20W halogen desk lamp). In the daytime over here from spring to fall it still works with light clouds, so over there it should generate some serious downflow ;-).AND: Sorry for the shop-page still being down. Stuff keeps getting in between doing something about that.

author: max666
author_rank: Frequent Contributor
timestamp: May 19, 2015, 08:22:48 pm
content: So what was it that got toasted on the ABB power supply?!I think you're trying to cover something up here, Dave. We wouldn't wanna ruin ABB's reputation, you know with all that quality written all over it.

author: dentaku
author_rank: Frequent Contributor
timestamp: May 19, 2015, 09:48:47 pm
content: By the way, I think if you check the brand of that big capacitor you'll see that it's "The Duck's Guts".

author: Stephan_T
author_rank: Contributor
timestamp: May 19, 2015, 11:04:24 pm
content: Quote from: nitro2k01 on May 19, 2015, 04:50:45 pmIf it tastes like armadilloit ischickenBTW. I have my fx-3800P since 33 years now and you are right Dave, as far as I remember, I had to change the battery not more than twice in all that time. I bought it when I started studying mathematics at university.One of my most favourite keys is ENG and Shift-ENG

author: bitwelder
author_rank: Super Contributor
timestamp: May 20, 2015, 05:40:03 am
content: Quote from: m100 on May 19, 2015, 05:28:57 pmFrom the Australian point of view almost *any* country is a Nordic country

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: May 20, 2015, 06:14:56 am
content: Dave - there was a Bug detection system that someone sent earlier and you opened it in another mailbag segment.Are you still planning to make a teardown of it?

author: reinhardz
author_rank: Contributor
timestamp: May 25, 2015, 12:22:16 pm
content: Quote from: Barny on May 19, 2015, 06:01:30 amThis meter has been manufactured by EAW = Elektro-Apparate-Werke Berlin-Treptow „Friedrich Ebert“ located in Eastern Germany = German Democratic Republic. I'm not sure but it could be that the range knob only seems to be flimsy because it has to be pressed in after selection of the appropriate measuring range.As to Metrawatt 2012 DMM: it's very easy to open it! Just press in the little leverhttp://www.bilder-hochladen.net/files/big/12b4-gm-3b72.jpg(red arrow)and the back ot the case can be pulled up. This DMM was - regarding its performance - rather cheap for DMMs of its time; it was very convenient to use for there was no need to unplug and re-plug probe leads when alternately measuring voltages and currents.Thanks for your great work!Best regardsreinhardz

author: f4eru
author_rank: Super Contributor
timestamp: May 25, 2015, 05:17:50 pm
content: "This capacitor is really the duck? guts"Lovely ....