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Thread: Jonny reviews lack the Hold Up Time test.

  1. #21
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    I've accepted new in the box units from people before. The key issue there is, they have to be new and once I'm done with them I can't send them back. Shipping is too expensive.

    So, most people choose not to do it.

    I've been meaning to discuss the idea of accepting Bitcoin donations with Tazz, but he's been rather sick lately and doing the taxes for this site will only make him feel sicker so I don't want to bother him with that idea right now.

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    Quote Originally Posted by sblantipodi View Post
    I don't know who is tony, is it your friend or someone who can share this instruments for your reviews?
    Tony is around, I just haven't been posting much on my end. I try to keep Jeremy setup with review samples and take care of the other stuff behind the scenes. I hope to upgrade Jeremy's equipment as soon as possible. I've got a lot of personal things going on in my life as well as a few health issues Im trying to resolve. So, I'm simply jumping 1 hurdle at a time.

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    Quote Originally Posted by Oklahoma Wolf View Post
    The problem is the Canadian dollar isn't worth what it used to be... not sure I could order one for that. Otherwise, I was thinking I haven't reviewed a Coolmax in a while.
    How about this one right here ----- COOLMAX ZX Series ZX-500? It says it's Crossfire rated and 80 Plus Certified (or should it be certifried ). I could spring for that one for you I think. Just doing a quick Google check, it looks like it would be around $50 US for me after converting to Canadian Dollars. If this one is acceptable for a reivew, PM me the correct amount to send you by PP and we can get a gutless wonder review on the way, Jeremy!

    EDIT: BTW, the link should be to the Newegg.ca site, so these should be your prices.

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    That's actually the exact one I had my eye on.

    Will have to get back to you - need to order a new card for my mining operations soon, and Newegg's where I was going to order it from.

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    Quote Originally Posted by Oklahoma Wolf View Post
    That's actually the exact one I had my eye on.

    Will have to get back to you - need to order a new card for my mining operations soon, and Newegg's where I was going to order it from.
    Let me know when you are ready to order and I'll get you the money. I'm presently on the rig right now, but I generally check the forums every day or 2. And I'll be off next week, but plan to go to the rifle range if the weather is good. Wanna burn some powder.

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    You don't have to buy a Chroma AC source to make a consistent hold-up time test.
    All you have to do is to make an MCU-based small device which cuts off the AC input (with a relay or solid switch) at a specific phase angle, for example, at the positive or negative peak of Vin. It may also generate a pulse as the trigger of osilloscope.
    It will only need a few hundred bucks, and a few weeks of work.
    It's been a hard day's night and I've been working like a dog.

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    Quote Originally Posted by Travis View Post
    It will only need a few hundred bucks, and a few weeks of work.
    I have neither a few hundred bucks nor the time required.

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    It might be easier/cheaper to do it using analog control. Maybe... Use a resistive divider to bring the voltage down, then use an LM393 comparator to find the peak voltage and kill the power with a relay? I could sketch a circuit if you want.

    EDIT: The BOM on something like that is lower than I was expecting. Triac or relay, optoisolator, LM393, LM431, 9V battery (or other voltage source), some <1% resistors, a couple transistors and passives. Most expensive part would be the PCB, but hell, you could probably build it on strip board.

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    Quote Originally Posted by CM Phaedrus View Post
    It might be easier/cheaper to do it using analog control. Maybe... Use a resistive divider to bring the voltage down, then use an LM393 comparator to find the peak voltage and kill the power with a relay? I could sketch a circuit if you want.

    EDIT: The BOM on something like that is lower than I was expecting. Triac or relay, optoisolator, LM393, LM431, 9V battery (or other voltage source), some <1% resistors, a couple transistors and passives. Most expensive part would be the PCB, but hell, you could probably build it on strip board.
    Yeah, with a stripboard you can reduce the total BOM to some dozens of dollars.

    The output of comparator should be latched so once the relay is triggered it will only be released after a power cycling.

    Vin -> isolation transformer -> resistor divider -> comparator gives a high output once the Vin crosses the threshold voltage -> the high level is latched and applied to the relay -> AC cut off.

    The idea is almost complete now. Let's do it.
    It's been a hard day's night and I've been working like a dog.

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    We can use a 555 configured as a one shot to generate the Trig pulse.

    We should put a fuse before the isolation transformer for safety, in case of a short.


    EDIT: We could also use the 393's extra channel to monitor a differentiator (type of high pass filter). This would give us a voltage related to dv/dt. This would give us two stage measurement, so we don't accidentally trigger on a transient. Not too much more complicated either, it's all passive components.


    I'll work on it after work and over the weekend.
    Last edited by CM Phaedrus; 03-20-2014 at 12:20 PM.

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