$12 Ham Radio Power Supply

Discussion in 'Amateur Radio News' started by KB1THM, Apr 26, 2020.

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  1. W2ND

    W2ND Ham Member QRZ Page

    I run the DPS-1200FB. I have been for probably 4 years now. They are 12v 75A and 110vac. I have added a couple resistors in mine to change the over voltage threshold and to adjust the voltage up to 13.8v. Mine is the HSTNS-PD11. There are different ones. I think there is a PD19 which is higher efficiency (uses like 40w less) but you will pay more for them for not a lot of difference. This particular model is very quiet until it gets hot then the fan will kick up to keep it cool. As for noise on radios?...... absolutely nothing. I can have 2 HF rigs running full 100w out on these during field day and not break a sweat. I currently have my HF, 2m, 150W car audio amplifier, and my swr meter light running on one at my QTH. Here is mine at 13.8v. I put rubber feet on the label side and turn them over. They stack nice and flat this way (the fan sticks out a bit otherwise). I also remove all the brass tabs and the latch and handle from them to clean them up. On the one pictured, I have added a power switch and the terminals. I had a video but it was too large to post and wrong file type. These things are very well build and very spectrally quiet. With ~20A draw on this supply pictured, it only sees 40mv drop. They are very solid supplies.

    Attached Files:

    K8AI likes this.
  2. K8AI

    K8AI Ham Member QRZ Page

    An old Chinese proverb says: "man who say 'it can't be done' should not interrupt man who is doing it."
    K0PV likes this.
  3. K4KYB

    K4KYB Ham Member QRZ Page

    better to use a MegaWatt switcher
    I have a mod board for the little HP power supplies to get them up to 14.5 Vdc I stacked 6 together and got 575 amps at 14.2 under full load
  4. NQ4T

    NQ4T Ham Member QRZ Page

    I have two server power supplies that put out 38A @ 12V.

    The only problem is they're powering the server.
  5. K2DJ

    K2DJ Ham Member QRZ Page

    I got the PD18 but it won't turn on with 1k resistor. If I jumped with a piece of wire it will start up. Pins 33 and 36. Ripple on output is about 101 mV. Connected a 8200uF x 25 volts electrolitic and the ripple goes down to 60mVpp. Nice.
    This power supply comes with too little output capacitors. I will put a bigger capacitors on output and upgrade the little ones at 16 volts that sits inside the power supply

    Attached Files:

  6. N9BSV

    N9BSV Ham Member QRZ Page

    Where exactly did you connect the 8200uF Capacitor? can you give us instructions to your mod? Thanks!
  7. K7JEM

    K7JEM Ham Member QRZ Page

    Usually for a switching supply, smaller low ESR ceramic capacitors are recommended to reduce ripple. Typically, large electrolytics are not as effective as the frequency goes up. Here is an interesting video demonstrating this:

  8. K2DJ

    K2DJ Ham Member QRZ Page

    I soldered just on the output pad. I want to try a bigger ones. I will try 10000 and 15000uF to see if any difference.
    As I said before. The little electrolitics on the output are like a joke. If you see the output electrolitics from any ham radio power supply is a huge difference.
    This is an easy and must to do upgrade, no doubt about it.
    But inside the power supply is not much room to put a bigger one so just need to upgrade the voltage to at least 25 volts and the biggest uF you can fit inside.
    On the outside soldered on the output pads you can use a bigger one!!
    Last edited: May 11, 2020
  9. K2DJ

    K2DJ Ham Member QRZ Page

    Thanks for the video. Well I try many different capacitors. But the ones that I see making the ripple goes down are the electrolitics. And the more uF i use the better!!!
  10. K4ECA

    K4ECA XML Subscriber QRZ Page

    Please note, HSTNS PL11 and similar.
    I have read on the internet, here and other forums, some of you are having Trouble getting the HP server supplies to start. Some are connecting pad 33 to pad 36 with a resistor and some with jumper wire and one I read said that 4 supplies needed a delay circuit to get it to start. I just finished start up on a HSTNS PL11. Here is some info that may be of use.

    Pad 33 PSON (power supply on). This pad is connected to 3.3v internal supply via a pull up resistor and should be connected to Pad 30 (12v GND/Return). Yes, Low=On

    Pad 36 PRES (supply present). This tells the supply that it is present in the back plane (plugged into the server) and ok to start. This pad is low and needs a 21k pull up resistor connected to the +12VSB (+12v stand by supply) Pad 37. Note, the pull up resistor is needed to limit current, there is a zener diode in the circuit. DO NOT use a jumper. Yes 22k is close enough.

    So if you connect pad 33 to pad 36, there will be a tug of war between the inputs. These are logic gates, one should be high and one should be low. Trying to use one against the other, well, I'm amazed it ever works.
    73 K4ECA, Bob
    Last edited: May 11, 2020
  11. WY7BG

    WY7BG XML Subscriber QRZ Page

    Surprised you didn't solder the resistor directly across the tabs on the PC board! How did you discover that it was needed, and what the value had to be?
  12. K4ECA

    K4ECA XML Subscriber QRZ Page

    MuRata makes a power supply with this 'standard'. Someone posted an application note from MuRata on thier web page. The note has info about what each pad is for and how it is used. The resistor value from my previous post came from the app note. I also found a schematic that someone posted of the exact HP P/S that I bought. This is how I knew about the zener diode.
    73 Bob
    Last edited: May 11, 2020
  13. K4ECA

    K4ECA XML Subscriber QRZ Page

    I had to bridge a smt resistor in the HSTNS PL11. I did not remove it, just soldered a very tiny piece for wire across the top. I made it from just 3 strands removed from #22 stranded wire, I pre-tinned of coarse. Leave it very long (so you have a handle to hold it) and cut the tag end off after soldering.
    73 Bob
    Last edited: May 11, 2020
    N9BSV likes this.
  14. N9BSV

    N9BSV Ham Member QRZ Page

    Thanks Bob, I will give that a try!
  15. N4HLT

    N4HLT Ham Member QRZ Page

    N9BSV likes this.

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