EEVblog #618 - Mailbag

[EEVblog]

! Private video

[TVman]

Oh Goody, Another man opening bags.

[Neverther]

Gen 1 tube is restricted? 
Dual gen 0 costs around 90$ here with helmet, HV supply and carry case with spare parts (PNV-57a, I bought one with broken supply from local store and fixed it).

There is a load of gen 2+ and 3s on US ebay for hunting and other sports.
Europe has old russian cyclops scopes (gen 1) and german Fero 51 surplus for sale.
Also, an UK seller has gen 2 philips tubes and australia is not excluded from the list....

[Zad]

Those oldschool UV-erasable PIC micros are great for educational tools, showing people what is inside a chip. Top tip: I don't have a fancy microscope, so I popped one on my flatbed scanner. 

[SeanB]

I was fixing those today. The transformer is 56VAC open circuit, but drops to 2V with the element. the timer is really simple, a half wave rectifier, a 4u7 capacitor and then a power resistor to drop 300V to drive the relay with 24V. The timing is set with a RC delay, with the 220k pot on the front providing the dalay along with a 47k resistor ( minimum time setting value) and a capacitor ( 10uF or 22uF depending on what they found), with a 6V8 zener diode driving the base of a NPN transistor that then drives the gate of a SCR ( CR02M on the originals, but I replace them with C106D when needed) that fires to short out the relay coil. LED is in series with the relay coil.

Most common failures are the relay burning a contact, and shorting to the coil cooking pretty much everything. I also add a VDR to tame the spike across the contacts as they open. Mechanically the elements burn the ends, and then you need new end pieces. The switches also burn out, but are easy to replace. I have enough of these at work, and keep a lot of spare parts for them.

[rsjsouza]

Great video. The TMS320 simply refers to all of TI's DSPs and the TMS320C5x development kit you have was very popular in its day. TI had published an entire set of assembly source files for a v.34 modem (here.

The messaging gadget seems quite clunky nowadays but, in technological terms, 2005 is "a century ago". The wireless world back then was very fragmented in solutions and the path to the smartphones was not yet clear for the consumer market (mostly Treos and Blackberrys for the corporate crowd...) - not to mention the charges for GSM/GPRS wireless data were astronomical at theoretically 114kbps, but far from it in practice.

That perhaps explains why a portable device with Wi-Fi at astounding 11Mbps (and free of charges) was an interesting idea... In the same year Palm released their Lifedrive with Wi-fi only (I still have mine), and all smartphones supported only SMS and e-mail...

[mozzwald]

The Zipit Z2 is an older device, but it's quite versatile since it's been hacked and can run a full Linux distro. There's still a good community around the Zipit which I am a part of. Here's a little info about it:

Made by Aeronix / Zipit Wireless
PXA270 CPU 312mHz, can be overclocked to 520mHz
Marvell 802.11b/g Wifi
1230mAh LI battery
WM8750BG Wolfson Audio chip
8MB NOR Flash
Rear port is a Hirose connector with USB, Audio, GPIO, Pwr, i2c, Pinout: http://bealecorner.org/best/measure/z2/z2-connector-pinout-2011.txt
Mini SD Slot on front (can be used with micro sd and adapter)
Test points for jtag and uart
Linux distros available: OpenWRT, IZ2JFFS (based on the stock/builtin linux), Arch, Debian

There's a bunch of info on my site http://mozzwald.com and I have a page of links to other info at https://mozzwald.com/node/171. Hop on irc.freenode.net channel #zipit if you have questions.