Author Topic: EEVblog #651 - Mailbag  (Read 16087 times)

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Online EEVblog

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EEVblog #651 - Mailbag
« on: August 12, 2014, 05:33:43 am »
 

Offline ElektronikLabor

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Re: EEVblog #651 - Mailbag
« Reply #1 on: August 12, 2014, 06:44:21 am »
Thank You for the teardown of my stuff, Dave.
I'm that guy from Norderstedt ;)

You asked where  the funky "recorder" with the chopper amp comes from: It was used for many years at the Technical University of Hamburg.
« Last Edit: August 12, 2014, 07:45:06 am by medvedev »
 

Offline Kjetil

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Re: EEVblog #651 - Mailbag
« Reply #2 on: August 12, 2014, 06:46:35 am »
Cool stuff again. A video on powering VFD's would be nice, got a few of them that I haven't got working.
You need a new hat now too, a crocodile dundee one, just with IC's instead of crocodile teeth  ;D
Scout leader and HAM radio operator
 

Offline Greg323i

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Re: EEVblog #651 - Mailbag
« Reply #3 on: August 12, 2014, 09:57:44 am »
Gossen Metrawatt was formally BBC Goerz Metrawatt. I'm not certain of the story/buyout/what have you, but I own a BBC Goerz Metrawatt DMM from the mid '80's (I was working in a wholesale electronics supplier and it was old stock, so got a deal on it). I contacted Gossen Metrawatt to see if they had a manual for the meter and they supplied me with a PDF copy, in German. It was all they had. Nice old school meter.
 

Offline JonnyBoats

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Re: EEVblog #651 - Mailbag
« Reply #4 on: August 12, 2014, 10:23:21 am »
Dave,

When are you going to open a can of beer with that knife?

In fact how about a teardown Tuesday where you literally rip apart some things with that knife; I bet the Energizer bunny wouldn't stand a chance ;-)
 

Offline slr4875

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Re: EEVblog #651 - Mailbag
« Reply #5 on: August 12, 2014, 11:58:34 am »
The Eurotherm device looks like a kiln controller.

Noritake Itron make very nice VFDs. Some are HD44780 compatible. Their products are a bit pricey but they usually have some items on special.
« Last Edit: August 12, 2014, 12:07:38 pm by slr4875 »
 

Offline m100

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Re: EEVblog #651 - Mailbag
« Reply #6 on: August 12, 2014, 12:03:22 pm »
'BBC' in this case being Brown Boveri & Cie of Switzerland, who merged with Asea of Sweden in the late 80's to become ABB
 

Offline rs20

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Re: EEVblog #651 - Mailbag
« Reply #7 on: August 12, 2014, 12:05:51 pm »
Regarding those multimeter-style switches -- the one with the big shaft coming from the front panel and going through a couple of switch units on those verticals boards -- what search terms should I be using to find those switch units on digikey/farnell etc for use in my own projects?
 

Offline xDR1TeK

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Re: EEVblog #651 - Mailbag
« Reply #8 on: August 12, 2014, 12:19:29 pm »
Must have knife!!!! Want knife now!!! Me go tinker!!!
 

Offline dentaku

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Re: EEVblog #651 - Mailbag
« Reply #9 on: August 12, 2014, 12:26:01 pm »
After you did your video about enclosures and how you wanted to mount the display for your power supply project I thought you should do a video on driving LCD/LED/VFD. They're incredibly easy to salvage from old electronics but often rather intimidation for beginners because you don't want to kill them by hooking them up incorrectly.
A video on driving/controlling/multiplexing displays would be nice too.

By the way, did you ever hook up one of Fran's Nixie tubes?
 

Offline max_torque

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Re: EEVblog #651 - Mailbag
« Reply #10 on: August 12, 2014, 12:47:50 pm »
Can we have an EEV sweepstake for how many "mailbags" it takes before Dave cuts one of his fingers off with that massive knife?

I'm going with 5.....   ;-)
 

Offline nathanpc

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Re: EEVblog #651 - Mailbag
« Reply #11 on: August 12, 2014, 02:10:37 pm »
It would be very interesting to see a video on salvaging and powering VFD displays.
 

Offline synapsis

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Re: EEVblog #651 - Mailbag
« Reply #12 on: August 12, 2014, 02:17:04 pm »
Haven't seen the whole video yet (Dave posts too late for some of us working Yanks!), but I do regularly work with Eurotherm units in industrial automation.

That unit is ancient obviously, and the unit series I work with most of the time is the 2400s (2404, 2408, 2416), but there are similarities.

Eurotherm still builds their temperature controllers the same way. There's a display board in the front (LED these days) with various boards stacked out the back. There's usually a power board (24VDC or 120/220VAC), and an analog board (for thermocouples, the ones I use are usually two channel type K.) Eurotherm sells option boards that plug into the unit. The options can be things like 0-10V/4-20mA analog retransmit of the process variable (temperature), relays that trigger on setpoints, or communication modules like RS422/485. The 2400 series has a chassis that you mount into a square hole in the panel, with the same type of contacts Dave had on his model. Then the unit has two tabs on the front that let you slide the whole inside of the controller out without removing the panel. The back of the chassis has screw terminals for connection to the rest of the system.

The menu system has a *lot* of settings on my units, with different security levels. Level 1 is for setpoints and possibly alarms. Level 2 is for more complicated things like PID parameters, deadbands, and option configuration.

I might be able to send Dave a 2404 (we have a box of parts somewhere around here) if he's interested. If anything he could use it to control his lab air conditioning. ;)
 

Offline Rory

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Re: EEVblog #651 - Mailbag
« Reply #13 on: August 12, 2014, 03:19:14 pm »
Is solder smoke easy to get off the microscope lens without damaging the ARAG coating? Or does it have a neutral density filter in front?
 

Offline sergey

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Re: EEVblog #651 - Mailbag
« Reply #14 on: August 12, 2014, 03:35:35 pm »
Just in case Sergey (if i type it correct :) reading this thread, i had the similar question couple of months ago, and if you search for "NEC LD8121"here on the forum you'll find a discussion how to power VFD up and know it's pinout.

Hope it helps :)
 

Offline Wytnucls

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Re: EEVblog #651 - Mailbag
« Reply #15 on: August 12, 2014, 04:04:04 pm »
Can we have an EEV sweepstake for how many "mailbags" it takes before Dave cuts one of his fingers off with that massive knife?

I'm going with 5.....   ;-)

I put my money on the bare toes, when that scimitar slides of the bench.... :scared:
 

Offline SeanB

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Re: EEVblog #651 - Mailbag
« Reply #16 on: August 12, 2014, 05:01:28 pm »
Like I said, the scanner was dropped by Ungaas, and she no work now. Still boots up to MSDOS though, which was interesting to say that it still would boot when I applied 5v to it. Of course with the tiny keyboard with only a numerical pad i was rather limited, likely it would respond to a serial link as well, or likely there is a regular XT keyboard controller interface inside there.
 

Offline Tek_TDS220

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Re: EEVblog #651 - Mailbag
« Reply #17 on: August 12, 2014, 10:04:28 pm »
Upside-down oscilloscope on the shelf - the electrons will fall out!!!

I've purchased several of the 1/4 DIN PID controllers, but not from this particular manufacturer.  They have a lengthy list of options, which are encoded in the serial number.  They are built from parts when you purchase them. They are bullet-proof, running 24/7 for 20 years.  I've never seen a failure when they are properly hooked up.  And yes, very difficult to program even if you have the manual.
 

Offline Smokey

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Re: EEVblog #651 - Mailbag
« Reply #18 on: August 12, 2014, 11:44:59 pm »
What PCB autorouters existed in 1985?
 

Offline coppice

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Re: EEVblog #651 - Mailbag
« Reply #19 on: August 13, 2014, 03:24:30 am »
What PCB autorouters existed in 1985?
Ah, good old 1985, when we used to watch our PCBs autorouting on 4k resolution screens. Its only 29 years later, and we are finally getting our 4k screens back. :-)

None of the currently popular autorouters were around in 1985, but there were several good ones back then. I just can't remember their names. That was the period when hand layout of ICs was becoming totally impractical, and there was intense research into more effective algorithms for autorouting. What was developed for ICs spilled over into PCBs, so PCB autorouting was moving forward pretty well then. A huge number of PCBs were still being laid out with black tape on mylar film, though.

I first autorouted a PCB in 1977. The equipment I used was about $300k, and the software was some horrendous price too.
 

Offline motocoder

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Re: EEVblog #651 - Mailbag
« Reply #20 on: August 13, 2014, 03:18:40 pm »
Cool stuff again. A video on powering VFD's would be nice, got a few of them that I haven't got working.
You need a new hat now too, a crocodile dundee one, just with IC's instead of crocodile teeth  ;D

While a video on VFDs would be nice, there are a lot of good resources about them on the Internet. See the Wikipedia page on the topic, particularly the External links at the bottom of the page. There is even a link to a simple test circuit there (uses 9V batteries and a 1.5V AA battery in series to generate the necessary voltages and filament current.

Wikipedia Page: http://en.wikipedia.org/wiki/Vacuum_fluorescent_display
Simple VFD test circuit: http://www.tubeclockdb.com/vfd-tubes/100-simple-vfd-tester.html
Great guide to VFD operation from Noritake: http://www.noritake-elec.com/vfd_operation.html
« Last Edit: August 13, 2014, 04:37:18 pm by motocoder »
 

Offline edpalmer42

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Re: EEVblog #651 - Mailbag
« Reply #21 on: August 13, 2014, 07:06:43 pm »
Dave,

I don't know what you're using for an anti-static wrist strap, but the two wrist straps in that medical device look like they have snap fasteners for the cables.  If the snaps are the right size, you've got two of the best quality wrist straps around.

Ed
 

Online PA0PBZ

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Re: EEVblog #651 - Mailbag
« Reply #22 on: August 13, 2014, 08:15:16 pm »
What PCB autorouters existed in 1985?

PC-based:

Altium (Protel)
P-CAD
ORCAD (maybe not '85)

And probably a lot I forgot..
Keyboard error: Press F1 to continue.
 

Offline IO390

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Re: EEVblog #651 - Mailbag
« Reply #23 on: August 13, 2014, 08:45:17 pm »
Funny to see Eurotherm there. They distribute some of my dad's stuff.
 

Offline Don Hills

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Re: EEVblog #651 - Mailbag
« Reply #24 on: August 14, 2014, 01:14:36 am »
...  the two wrist straps in that medical device look like they have snap fasteners for the cables.  If the snaps are the right size, you've got two of the best quality wrist straps around. ...

Er... no, for at least two reasons.

First, they're metallic. Think short circuit.

Second, they are unlikely to have the required resistor in circuit between the bracelet and the strap.
 


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