9 comments on “Technical Night washup – 25th November 2016

  1. During the course of the meeting I mentioned that my 60 amp rated switching power supply is rated at 60 amps, but that users indicate that is an unlikely figure, to which Rob replied “have you tested it for maximum amperage”.

    Well, firstly why would I need to do that, since 25 amps is enough for most of our needs.

    Secondly, my understanding is that what you absolutely do not want to do is to put the supply under a high load and see if it “can handle it”. Even if it does handle it for that moment, it might be permanently damaged– and damaged in a way that will only show up later when you are away and your house burns down.

    So, If I received a power supply that wasn’t marked, I would never power it up. Instead I would throw it away. Electrical Engineering has some hazards that are not worth tempting. This is one of them.

    The fact is that you need real-lab testing equipment to determine the max. current of a power supply, so Rob’s question is really in the realms of fantasy & impractical for plebs.

  2. A great session……..mainly but not entirely, Nige.

    He knocked the internet, yet from his presentation it seems he spends a lot of time there getting information.

    So HE can sort the wheat from the chaff. He should be aware of the need to give the rest of us credit, those of us who are also intelligent enough to do the same.

  3. Stu,

    Could you supply the names of some currently available 12v server power supplies that you would recommend to work up too 25W, with transceivers.

    I notice online there that may be a need to convert them in some respect. Would you care to comment?

    Thanks

    • Stu’s brief comments about server power supplies grabbed my attention, so I researched it.

      These power supplies require conversion for use with amateur radio. Their conversion requires serious technical knowledge that most of us don’t have. This is no simple 555 oscillator guided project, such as Trev’s.

      For the most part they have no manufacturer documentation & the conversion needs vary from brand to brand & model to model. Perhaps, only someone in the industry would be acquainted with their specs, although apparently some hobbyists are prepared to test their less than optimum knowledge, with a skew of outcomes.

      For those interested, perhaps the committee would be prepared to consider technical night/s devoted to the practical conversion of a specific unit for each such member, with step by step guidance from Stu. Otherwise, we can consign theory on the subject to the growing archive of information.

      • Not sure what conversion is needed. Simply identifying the correct pins to ‘turn it on’ is all the conversions I have ever needed to do, hence why I suggested it as a simple way for members to to get themselves a good quality high power PSU. Been running a few PSU’s like this for a number of years with no issues. Certainly my experiences are echoed in other hobbies that use these PSU’s as high capacity 12v supplies.

        Aside from soldering (which has been the topic of a few tech night hands on sessions) and knowledge of which pins to connect where, there is no other information or skill set required.

        Specs are readily available on the Internet, or by mail if you wish to contact the manufacturer and negotiate the printing and mailing of one – I suspect.

    • HP ESP-115 (30 amps)
      Dell NPS-730AB A REV A01
      Hewlett Packard HP-194989 (400W, 32A max. on the 12v line)
      Hewlett Packard HP-280127 (325W, 26A max. on the 12v line)

      …are just a few. eBay will list many different models, just check the rating on the 12v supply to ensure it will delivery the current/power you need.

  4. Done several searches on google for pinouts of Delta PS
    AWF-2DC-760w…….with no joy at all…has anyone had luck.
    Bob
    vk5lbw

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