Switching Power Supply Repair - worth it? Thoughts on replacement.

Discussion in 'Ham Radio Discussions' started by KJ5T, Jul 29, 2020.

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  1. N7EKU

    N7EKU Ham Member QRZ Page

    Hi,

    A switching supplly is MORE efficient than a linear so it, in general will run cooler and use less power. As such, it can get by with very small heatsinks for most of the time and it can be made quite light and small. However at higher loads, the small heatsinks inside will need some active cooling (fan).

    Linear supplies use a large iron transformer, and they traditionally go ahead and use a large spacious case and large aluminum heatsinks for the pass transistors which are constantly generating heat (at idle a typical ham linear supply will generate 25W just sitting idle - that's about $2/month). But they can be made more compactly like the listed one and in that case they will need a fan to keep them cool.

    As far as the current broken one goes, I would try to fix it. Most of the parts on the input circuit would be very easy to check for even a beginning repair person so an experienced one should have no trouble.

    73,


    Mark
     
  2. WA9SVD

    WA9SVD Ham Member QRZ Page


    Yes, I well understand all that. But one of the ADVANTAGES of a linear supply (at least at the 25-35 Ampere level) is silent operation. Needing a fan can (and often does) negate that feature, and IS just "one more part" that can, and usually will, go wrong throughout the life of a supply. I don't know of any fan, running continuously, that can last 30 + years...

    Fixing a switching supply is often a 'toss-up." If the co$t of new parts (IF still available, or can be identified) along with the time spent is 1/2 (or more) than the price of a new unit, it may be simple economics to purchase a new unit, which will normally come with a warrantee; that is missing with a DIY repair.
     
  3. W4NNF

    W4NNF XML Subscriber QRZ Page


    The DM-430T is a switching power supply. I don't believe Alinco makes a linear power supply.
     
  4. WA9SVD

    WA9SVD Ham Member QRZ Page

    The link above (Post # 32) lead to a YAESU supply that is LINEAR. THAT is the supply to which I referred. What does an Alinco switcher have to do with things?
     
  5. W4NNF

    W4NNF XML Subscriber QRZ Page


    Go back and read it again. I was simply talking about power supply fans in general. Sorry if I annoyed you somehow, OM. :(
     
    Last edited: Aug 1, 2020
  6. W9RAC

    W9RAC Platinum Subscriber Platinum Subscriber QRZ Page

    I do have the Alinco DM-430T that Rod spoke of also. Looks like they have cheapen them up a tad since I purchased mine. I use it with a FT 450d outside for some CW work since its light. It does have a fan that can be a bit noisy if you push it. I realize switching vs linear can be decided upon different ways however there really no comparison between it and the Yaesu 1030A I spoke of earlier. Good luck finding what works for you best, 73 Rich

    DM-430T 001.JPG
     
  7. N7EKU

    N7EKU Ham Member QRZ Page

    Hi,

    In part, I was merely responding to a question about why the Yeasu needed a fan. Someone did say they were confused I thought. As to why Yaesu decided to do it that way, I guess to make a more compact unit that would match their rigs. I had a kenwood linear in the past that had a fan for I expect the same reason. And I was in general just talking about the advangtages and disadvantages of each type.

    For sure linears with no fan are so quiet and nice for that characteristic. They also make no RFI and are very low maintenance.

    The efficiency and low weight of a switching type are nice too though. A linear in continuous operation just idling costs about $25/year so if you leave your power supply on all the time, that is something to consider. And if you live in a climate that requires AC most of the time, it would cost at least that much again in added cooling costs. Also, the fans on switching types generally don't run continuously, but only under bigger loads.

    73,


    Mark


     
  8. W9RAC

    W9RAC Platinum Subscriber Platinum Subscriber QRZ Page

    Mark the Yaesu 1030A is a heavy duty power supply. 25 amp continuous duty. The fan is temperature controlled, if it comes on and if is audible you are working hard. A switching supply would have given up long before. Its power is clean. Great unit. 73 Rich
     
    Last edited: Aug 1, 2020
    WA9SVD likes this.
  9. KP4SX

    KP4SX Premium Subscriber QRZ Page

    How can you say that without specifying which switching supply? I'm sure there are ones out there capable of 25A continuous duty.
    Samlex SEC-1223 is rated for 23A continuous, Yaesu FP-1030A is rated for 24A continuous.
     
    Last edited: Aug 1, 2020
  10. W9RAC

    W9RAC Platinum Subscriber Platinum Subscriber QRZ Page

    Not to be argumentative or make an effort by being contrary to the statement, I would never leave a power supply on at idle, why would one consider doing that. 73 Rich
     

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