ALS-600 replacement power supply

Discussion in 'Amateur Radio Amplifiers' started by K9UR, Dec 18, 2019.

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  1. K9UR

    K9UR Subscriber QRZ Page

    Neighbor ham has an ALS600 RF deck and the power supply was lost. I am pretty sure these use +50VDC and +13.8VDC. I've peeked at a schematic and it shows -13.8VDC too, but I couldn't figure out what that does other than drive the power supply volt meter ?

    Anyway, I'm suggesting we try to get a cheap blade server 50V / 30A power supply plus a cheap 13.8V switcher, throw them both in a small metal box, and have a really nice and light weight 500W-class amp for portable use.

    Thoughts on a (cheap and easy) replacement power supply ?
  2. VE2GCE

    VE2GCE Ham Member QRZ Page

    Most switching supplies can cause all kinds of RFI, unless they are specified designed to work in a ham environment (like the original ALS600 switching supply).
    Power supplies intended for amateur-use have significant filtering compared to general purpose computer and networking power supplies.

    An analog supply is an option, but is considerably bulkier and heavier.
    Last edited: Dec 18, 2019
    K0UO likes this.
  3. K9UR

    K9UR Subscriber QRZ Page

    Yep. True. But I think with enough ferrite chokes, torroids, and double-chassis/metal shielding, most of today's switching PS should work.

    Here are the schematics that i could find....

    PS_600_Wiring.JPG PS_600.JPG PS_Board.JPG
    Last edited: Dec 18, 2019
  4. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    MFJ, has brand-new Replacements Solid State power Supplies for the 600.

    They used to sell a lot of them because people were replacing the old heavy Transformer which I like the most.

    I know some guys upgraded, so there should be some older Transformer supplies available also.
  5. WA4SIX

    WA4SIX Ham Member QRZ Page

    The HP blade server supplies are used by many hams for LDMOS amps with no issues.
    The 12VDC may also be used for biasing.

  6. VE2GCE

    VE2GCE Ham Member QRZ Page

    That is not surprising. HP is the epitome of quality.
  7. WA4SIX

    WA4SIX Ham Member QRZ Page

    30 amp units are about $35 + shipping. There are others that are a better form factor & have 12 amps of 12VDC & some 5VDC.
    I scored a 60 amp 50VDC unit that has 30A 12VDC & 12A 5VDC for $68 shipped. It is silent to all of my gear, including a LineSDR-USB. It is actually a 30A supply with a redundant twin. Jumper settings can make it 60A total, 30+30A or redundant.

  8. N8FVJ

    N8FVJ Ham Member QRZ Page

    I seen 48 volt @ 50 amp used switching power supplies for $25 on ebay.
    K9UR likes this.
  9. K9UR

    K9UR Subscriber QRZ Page

    Yes, this is along the lines of what I was looking for. MFJ wants "just" $600 for a replacement power supply...pass...
    These will do just fine for ham radio use. Do you have a model number or link? I'd like to get one like you have...that's exactly what I think I need.
  10. K9UR

    K9UR Subscriber QRZ Page

    Yes, my goal was to perhaps find a multi-voltage supply- but collecting a couple separate supplies would work too... cheap and easy.

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