EEVblog #951 - Mailbag

[boffin]

• A watch made from a old IBM Microdrive Hard Drive Drive! http://hddwatches.com/
• Tearing down and debunking a Hyper Voltage Stabiliser car energy smoothing bullshit device.
• Panduino Uno compatible Arduino
• Dell Server destroyed by super Neodymium magnet! Brainiac75 Youtube
• My Playhouse Youtube:
• Hardware Hacker book by Bunnie Huang https://www.nostarch.com/hardwarehacker
• BMW 5 series keyfob receiver teardown
• ESD Wriststrap teardown
• CCCP Ohmeter
• Wun Hung Lo brand GoPro/SJCAM ripoff camera tested
• Dodgy battery charger
• 4 banger calculator

And, if you start pinning out the missing chip on that battery stabilizer, you'll find it's a 555 timer, to make the LED blink. Obviously that's the for the enhanced "Turbo Hyper Voltage Stabilizer"

[MK14]

[EEVblog]

Dave, if you start pinning out the missing chip on that battery stabilizer, you'll find it's a 555 timer, to make the LED blink. Obviously that's the for the enhanced "Turbo Hyper Voltage Stabilizer"

LOL!

[boffin]

Dave, if you start pinning out the missing chip on that battery stabilizer, you'll find it's a 555 timer, to make the LED blink. Obviously that's the for the enhanced "Turbo Hyper Voltage Stabilizer"

LOL!

about 50% @ 0.6Hz if my math is right for the 470k / 18k / 2u2

[TheAmmoniacal]

I couldn't tell if the HDDWatch works as a watch, or if it's just for show. Do the minute/hour hands move at all?

[bktemp]

At 44:12 while showing the 4 pin hall sensor on the fan pcb to the camera: "...there is no hall sensor..." 

If the schematic in the motor driver datasheet matches the circuit on the fan, I don't think an overvoltage generated by the coil windings could destroy the controller ic: There are external mosfets and the feedback is done using a hall sensor, so there is no direct connection between coils and ic. The only thing I can imagine happening is destroying the mosfets.

[EEVblog]

At 44:12 while showing the 4 pin hall sensor on the fan pcb to the camera: "...there is no hall sensor..." 

LOL, yeah, missed that.

[Someone]

At 44:12 while showing the 4 pin hall sensor on the fan pcb to the camera: "...there is no hall sensor..." 

If the schematic in the motor driver datasheet matches the circuit on the fan, I don't think an overvoltage generated by the coil windings could destroy the controller ic: There are external mosfets and the feedback is done using a hall sensor, so there is no direct connection between coils and ic. The only thing I can imagine happening is destroying the mosfets.

From a strong external magnetic field its likely saturation/magnetisation of the "permanent" magnets and/or the field laminations. Not electrical stress, with a small outlier chance of magnetisation of the hall sensor so it will no longer start.

[jonovid]

A watch made from a old IBM Microdrive Hard Drive Drive! http://hddwatches.com/

like the watch.      but the disc should move or something.  maybe add a second hand from the drive arm swinging on its post?

Dell Server destroyed by super Neodymium magnet! Brainiac75 Youtube

Neodymium magnets also do wonderful things to pub poker machines. just be sure to exit the room for before thay figure out who
tripped off a security network shutdown of all machines.

[Barny]

Clive had a go with an fan of this server:


The mail bag video had some strange cuts & some strange audio (not the crap-camera section)

[testian]

The mail bag video had some strange cuts & some strange audio (not the crap-camera section)

Just watched the new video and also noticed that.

But do you think, like Dave, the "The Hardware Hacker: Adventures in Making and Breaking Hardware" book is worth a read? Sounds very interesting but unfortunately I cant find a preview of the book.

[Carl_Smith]

Don Hoover, your entry for the worlds most dodgey battery charger contest is rejected.  Way too many parts. 

I have several Black and Decker screwdrivers that use the cylindrical "VersaPak" batteries.  The charger is nothing but a transformer, one resistor, and the "charging" LED.  That's it.  They use the charging indicator LED as the rectifier and just cook the battery with half wave rectified AC.  The batteries will be damaged the first time you forget them in the charger for more than 8 to 10 hours. 

I've bought new batteries and remembered to only put them in the charger for 8 to 10 hours and then remove them, and they lasted fine for a year or two, then I forget them in the charger for a few days and after that their capacity is greatly reduced and they don't hold a charge for more than a few days because of the damage by overcharging.

Also, I have a cheap battery powered toothbrush with an inductive charging base. I took the brush apart once just out of curiosity and the charging circuit in the brush is just a coil, diode, and battery. If you leave it in the base all the time it is always warm. I realized right when I got it, long before taking it apart, that it wasn't doing proper charge control. The warmth is due to the battery being overcharged. So I only plug the charger base in when the brush actually starts noticeably slowing down, and then I only leave the charger plugged in over one night. The thing is, I can use it twice a day for probably two weeks before it needs to be charged again. So that means when most people just leave the charger base plugged in, it's cooking the battery most of the time. It only really needs about 8 hours on charge once every two weeks.

As much as I usually hate the government meddling with things, I've seen so many of these dumb charger circuits that I think they should make a law that requires proper charger circuits that don't kill batteries.

[bktemp]

Don Hoover, your entry for the worlds most dodgey battery charger contest is rejected.  Way too many parts. 

Yes, if you want to see really dodgy ones, look at Big Clive's Youtube channel. How about charging a 3.6V lithium battery using 12V + a resistor?

[Carl_Smith]

Don Hoover, your entry for the worlds most dodgey battery charger contest is rejected.  Way too many parts. 

Yes, if you want to see really dodgy ones, look at Big Clive's Youtube channel. How about charging a 3.6V lithium battery using 12V + a resistor?

Ouch.  At least the bad NiCd/NiMH chargers probably won't set your batteries on fire.

I watch Big Clive but he posts so much stuff I can't keep up with all of it.

[Luminax]

My brother used to work in an auto parts shop that does peddle those stabilizer thingie... I think one of them was labelled "Ultimate bateri turbo stabilizer" or some other dumb BS... got my bro to nick a few of them for the aluminium casing.
They make for a rocking small amplifier case!

[Brumby]

I was thinking the case had some appeal as well.

You have to wonder, though, why the PCB?  Perhaps it was just for show if someone did open it up.

I was on board with Dave's capacitor prediction from the word go, but I really cracked up when he started reading out the 'features'... From the "Yeah, okay" to the "Huh?" to the ROFLMAO.


Oh man ...... If I had no scruples, I could be a millionaire.

[Luminax]

Those features were.... 
Followed with 
And some 

Sorry for the flood

[EEVblog]

The mail bag video had some strange cuts & some strange audio (not the crap-camera section)

Just watched the new video and also noticed that.

I just switched to Sony Vegas 14 and have had some rendering issues so maybe that's it?

[EEVblog]

Don Hoover, your entry for the worlds most dodgey battery charger contest is rejected.  Way too many parts. 
I have several Black and Decker screwdrivers that use the cylindrical "VersaPak" batteries.  The charger is nothing but a transformer, one resistor, and the "charging" LED.  That's it.  They use the charging indicator LED as the rectifier and just cook the battery with half wave rectified AC. 

I've seen that too. I thought it would just be a dropper, was surprised by the complexity in this one 

[bitwelder]

It seems Dave has completely missed/skipped to show the iSesame spudger (around 7:35).
As I've seen briefly that tool already in Big Clive's hands, it would been nice to hear what's Dave opinion on it.

[Kleinstein]

The more detailed tear-down from clive's video gives a few more clues to why the fan might have failed.  Looks like damage done from to much current / voltage. It could be an indirect damage:
The magnet could influence the power supply to give more than 12 V to the fans (and hard drives) and this could very well blow zeners in that position. Some power supplies use transductors to regulate some of the output voltages and these are known to be sensitive to a strong magnetic field. Still a little surprising it is enought to blow the zeners. 

[guido]

The EA logo is Electronic Arrays.

I have an IC lying around (EA2022 1979), but i could never find any info on it.
It's in a box with other unknown silicon objects.