• Re: highly stable AC->DC power supplies

    From john larkin@3:633/10 to All on Friday, March 27, 2026 12:35:54
    On Fri, 27 Mar 2026 08:33:24 -0800, Christopher Howard <christopher@librehacker.com> wrote:

    One of the old simulator systems I maintain is a non-qualified sim that
    we got out of a junkyard and we put back together to use for procedural >training and such like. So, for context, the general goal is to spend
    the least amount of money needed to keep it working as is.

    I've been having some trouble with a few of the components lately, and
    after a bunch of troubleshooting, I believe the problem is that the 5V
    60A and 12V 40A DC power supplies that feed them are not stable enough
    on the output. I.e., too much voltage variation under heavy load. The >components in question are specified to only accept up to 100 mVp-p
    ripple, but I'm seeing up to 200 mVp-p variation on the 5V supply, and
    up to 400 mVp-p on the 12V supply.

    The power supplies in place are some very cheap models obviously of
    Chinese extraction. And I think they are old as well, maybe around 20
    years. So I'm wondering if I can fix my problem by purchasing new,
    higher quality power supplies. But after looking around on the Internet
    for a little while, I'm not sure what are the best brands, companies, or >models to look toward. Any thoughts?

    We use a lot of MeanWell supplies in our products and they are very
    good. We use a 1KW 48V supply that costs about $170.

    But you should get one and test it for ripple. You might add a filter.

    Use remote sense.


    John Larkin
    Highland Tech Glen Canyon Design Center
    Lunatic Fringe Electronics

    --- PyGate Linux v1.5.13
    * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)
  • From TTman@3:633/10 to All on Friday, March 27, 2026 23:23:10
    On 27/03/2026 16:33, Christopher Howard wrote:
    One of the old simulator systems I maintain is a non-qualified sim that
    we got out of a junkyard and we put back together to use for procedural training and such like. So, for context, the general goal is to spend
    the least amount of money needed to keep it working as is.

    I've been having some trouble with a few of the components lately, and
    after a bunch of troubleshooting, I believe the problem is that the 5V
    60A and 12V 40A DC power supplies that feed them are not stable enough
    on the output. I.e., too much voltage variation under heavy load. The components in question are specified to only accept up to 100 mVp-p
    ripple, but I'm seeing up to 200 mVp-p variation on the 5V supply, and
    up to 400 mVp-p on the 12V supply.

    The power supplies in place are some very cheap models obviously of
    Chinese extraction. And I think they are old as well, maybe around 20
    years. So I'm wondering if I can fix my problem by purchasing new,
    higher quality power supplies. But after looking around on the Internet
    for a little while, I'm not sure what are the best brands, companies, or models to look toward. Any thoughts?


    Could it be as simple as replacig the bulk storage/smothing caps?
    -especially if it's that old.

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  • From Edward Rawde@3:633/10 to All on Friday, March 27, 2026 20:23:53
    "TTman" <kraken.sankey@gmail.com> wrote in message news:10q73gv$5ne7$1@dont-email.me...
    On 27/03/2026 16:33, Christopher Howard wrote:
    One of the old simulator systems I maintain is a non-qualified sim that
    we got out of a junkyard and we put back together to use for procedural
    training and such like. So, for context, the general goal is to spend
    the least amount of money needed to keep it working as is.

    I've been having some trouble with a few of the components lately, and
    after a bunch of troubleshooting, I believe the problem is that the 5V
    60A and 12V 40A DC power supplies that feed them are not stable enough
    on the output. I.e., too much voltage variation under heavy load. The
    components in question are specified to only accept up to 100 mVp-p
    ripple, but I'm seeing up to 200 mVp-p variation on the 5V supply, and
    up to 400 mVp-p on the 12V supply.

    The power supplies in place are some very cheap models obviously of
    Chinese extraction. And I think they are old as well, maybe around 20
    years. So I'm wondering if I can fix my problem by purchasing new,
    higher quality power supplies. But after looking around on the Internet
    for a little while, I'm not sure what are the best brands, companies, or
    models to look toward. Any thoughts?


    Could it be as simple as replacig the bulk storage/smothing caps? -especially if it's that old.

    Yeah that's what I thought.
    Old power equipment likely means old electrolytic capacitors which are drying up.
    A visual inspection might be revealing.


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    * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)
  • From legg@3:633/10 to All on Saturday, March 28, 2026 09:39:12
    On Fri, 27 Mar 2026 23:23:10 +0000, TTman <kraken.sankey@gmail.com>
    wrote:

    On 27/03/2026 16:33, Christopher Howard wrote:
    One of the old simulator systems I maintain is a non-qualified sim that
    we got out of a junkyard and we put back together to use for procedural
    training and such like. So, for context, the general goal is to spend
    the least amount of money needed to keep it working as is.

    I've been having some trouble with a few of the components lately, and
    after a bunch of troubleshooting, I believe the problem is that the 5V
    60A and 12V 40A DC power supplies that feed them are not stable enough
    on the output. I.e., too much voltage variation under heavy load. The
    components in question are specified to only accept up to 100 mVp-p
    ripple, but I'm seeing up to 200 mVp-p variation on the 5V supply, and
    up to 400 mVp-p on the 12V supply.

    The power supplies in place are some very cheap models obviously of
    Chinese extraction. And I think they are old as well, maybe around 20
    years. So I'm wondering if I can fix my problem by purchasing new,
    higher quality power supplies. But after looking around on the Internet
    for a little while, I'm not sure what are the best brands, companies, or
    models to look toward. Any thoughts?


    Could it be as simple as replacig the bulk storage/smothing caps? >-especially if it's that old.

    I refurbished 'high quality' supplies used in flight simulators for
    NAVCAN in the 90's. The computer grade electrolytics used on the
    outputs of lower-voltage single-output units were invariably
    cooked.

    As these used 2-stage filters, when the stressed section failed, the
    second stage masked the issue.

    I think they were located on-site in a sealed wooden box, or something
    similar, with little air circulation.

    RL

    --- PyGate Linux v1.5.13
    * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)
  • From someone@3:633/10 to All on Monday, March 30, 2026 23:30:02
    What is the frequency of the ripple? It could be a seemingly unrelated input grounding problem corrupting the regulator reference portion of the supply. It will be better to repair or improve the performance of what you have, unless you have a lot of money to spend.

    --
    For full context, visit https://www.electrondepot.com/electrodesign/highly-stable-ac-dc-power-supplies-4399872-.htm


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