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    EEVblog #821 – Mailbag

    EEVblog #821 – Mailbag

    More Mailbag! Extended Teardown Video HERE Forum HERE SPOILERS: Military Mystery Item Teardown – UPDATE: ...

    • Lefuneste

      What a laugh with the commercial junk!! I think I woke the neighbours up… And BTW I agree with you 200% about the medivial treatment for makers of these bloody blisters. I have dedicated myself to the improvement of slow death techniques for these folks…

    • http://JeanFrancoisAvon.com/ JFA in Montreal

      In many mailbags, you open only a small portion of the packages. I wonder why you didn’t open them leftovers instead of all the junk in the present one. Or maybe you get deluged by commercial junk? What a waste of precious time, looking at commercial promotional junk like pens! I cursed these spammers, and I think they deserve the same slow death as those who package their stuff in sealed plastic ! :-)

      One of these days, I’m gonna send you stuff from my WW-II batcave stash, still very useable (and still used) today. :-) In the meantime, keep up the good work !
      JFA in Montreal.

    • Orpheus

      We used to get syringe pens and incandescent penlights (actually useful for exams–you don’t want to blind your patients) 20+ years ago from drug reps. We can’t actually use those pens around patients, though. They can’t focus on anything else, fearing that we’re going to sneak-inject them

    • ac

      Hi Dave.

      Could you do a short video on what are the facts around this popular trick. I’ve haven’t had the guts to try it as it sounds risky to me but I don’t know if it really is. I only think if the fan or other thing would short, then you’d have a problem right?

      “Is the 7 volt fan silencing mod dangerous to power supplies or other components? ”


      “I remember for sure is that if you had something else that was creating a load on that rail from the PSU then you were safe to use the 7 volt trick. ”

      “I know this is a common mod and all but can someone with a better understading of the electronics explain why it’s not harmful to the PSU. I mean we are basically touching the 12 and 5 volt lines together right? Load on 12, ground on 5 volt….How does that not throw off the stability of the voltage rails? “

    • ac

      The belief I have is that if the Fan+ is 12v and FanGnd is +5v, wouldn’t the fan motor cause ripple on the +5v rail. Could a 12v fan running at 7v on such setup have any measurable effect on the 5v input to other equipment (lets say sensitive audio stuff) on the rail? Can you test this.

    • Warren

      What funny irony is it that the clamshell opening knife is sealed in its own disgusting clamshell!

    • huh

      Nice little multimeter with typical late 70’s to early 80’s style case, looks like it was designed by Sir Clive Sinclair himself:)

    • Nils

      Here in the US we call them blinkers, too, or just “turn signal”. The red stuff on the back of the blinker module is most likely a lacquer. In auto parts stores you can buy a spray can called “battery terminal protector” or something to that effect. It’s red (pink if you spray it thin enough, but I’ve never met any mechanic that believes in putting on only a little of anything) and you spray it on the bare metal of battery terminal connectors to prevent corrosion. Love the blog, great video as usual.

    • mamut

      The relay contacts of the blinker are also connected to the circuit, because like in modern cars the resistance of the light bulbs is also related to the blinking frequency. There is a RC like circuit in which the light bulbs are part of the R part!

    • achim1989

      Hi Dave,

      the coloured strips you took out of the box at minute 27 and want to give to Sagan are very useful for marking pages in books. I used a lot of them in my studies because they are very useful if you work with library books.

      Keep up the good work!

    • Mike

      The thing from Digi-Key is a letter holder. Probably not used much anymore. My father kept one on his desk and that’s where the important mail went, such as bills to be paid.

    • http://www.aykira.com.au/ Keith

      Funny mailbag – those promo products and the commentary had me and my wife in stitches (she used to work in marketing and agrees totally with your assessment).

      Keep up the good work!

    • Chris

      Blinkers in UK are generally called Flashers or Indicators.

      21W is standard rating for the front and rear bulbs, 4W for the side repeaters or a warning light.

      Bulb resistance is used in the circuit to vary the flash rate which indicates a bulb failure by flashing about twice as fast. Legally required audible warning is provided by the mechanical clicking of the relay armature against the pole piece, otherwise a fully solid state solution would probably be cheaper, but not isf an additional sounder is required. It also sounds the same as the old thermal units so no surprises for the uninitiated.

    • http://example.com Lucian Canacheu

      hi dave,
      CCCP means SSSR – it’s spelled in cyrillic.

      the integrated circuit next to the relay in the russian blinker is here


      the other one is here


      speaking of the iskra multimeter, check out these guys:
      they do exist nowadays.

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