EEVblog #745 - Mailbag

[EEVblog]

Mailbag time again. Dave opens his mail. What random stuff awaits?
Forum:


SPOILERS:
A vintage Japanese Sharp X68000 home computer from the 1980's
Teardowns 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 Sagan
Two Kickstarter Projects:
Femtocow USB912
https://www.kickstarter.com/projects/femtocow/usb-912
Bluetooth Audio Link (BAL)
https://www.kickstarter.com/projects/doayee/bluetooth-audio-link

A solar powered propeller hat and electronics business card:
http://shop.asmyldof.com/

Multimeter chipset:
http://datasheets.maximintegrated.com/en/ds/ICL7136.pdf

[redshift]

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 

[EEVblog]

Also, are Nestle chocolates popular in Australia? Because the last time I was in New Zealand they were nowhere to be found.

Yep, shelves are full of them.

Edit: I forgot to mention that you have to press down on that X68000 handle to release it 

Doh!
This one doesn't work that great.

[PaulS]

You missed the perfect opportunity to say "2-minute teardown!" before opening the chocolate.

[djQUAN]

Green tea Kitkat. Mmmm. They got various flavoured Kitkats there. Give it a try, it's good

[Barny]

A little hint:
Video time 36:18 -> Elektrische Daten
Thats german for electrical data

And below are the technical data for DC (Gleichstrommessung) and AC (Wechselstrommessung).

[Rasz]

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

[forrestc]

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.

[RobHeffo]

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.

[vlad777]

 I will never part from this. Dave. Never!
 Don't expect it in the mailbox.

[Fungus]

"Duck" is a brand of duct tape:

http://www.duckbrand.com/products/repair-project-duck-tape/original-duck-tape-reg

That's where the confusion comes from.

("Professional Strength" ... oooh!)

[bktemp]

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.

I 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.

[c4757p]

Duct/duck tape: have a look over the first few paragraphs here: http://en.wikipedia.org/wiki/Duct_tape

[djQUAN]

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.

I 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.

I 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.

[nathanpc]

Did anyone else notice those plastic standoffs on the TO-220 legs?

[djQUAN]

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.

[nitro2k01]

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...

[SL4P]

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...

But does it quack?
(If it looks like a duck, and sounds like a duck... then it might not be a chicken.)

[VK3DRB]

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/

[Fungus]

Wow. I thought I was the only nerd/dag/dork/geek who had fun computing 69 factorial on a calculator to tests its speed.

Been there. Done that.

I'm surprised they never cheated and stored that result in ROM to fool the 'benchmarkers'.

[Muttley Snickers]

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...

The sender might be slightly annoyed that Dave used the wrong knife...


Muttley

[vlad777]

" US net debt... http://www.usdebtclock.org/ "

WOW. It's good that it takes exponential to get to those high decimal digits...

[nitro2k01]

But does it quack?
(If it looks like a duck, and sounds like a duck... then it might not be a chicken.)

Also, if it smells like chicken and screams like a pig, it's probably holding the soldering iron wrong way around.

[m100]

At around 21 mins in did I really hear Dave call the Netherlands a Nordic country?       

[SeanB]

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.