[Lowfer] A power supply head scratcher

Sun Apr 18 12:52:35 EDT 2010

Have you tried an MOV across the AC line, which would clip the spikes, that initiate the shut-down?

                                    Ron

> From: jrusgrove at comcast.net
> To: lowfer at mailman.qth.net
> Date: Sun, 18 Apr 2010 06:46:50 -0400
> Subject: Re: [Lowfer] A power supply head scratcher
> 
> Andy
> 
> One last thing to try if you haven't already...
> 
> Put a load resistor on each of the power supplies individually rather than across the combination. 
> If that doesn't work, open them up and scavenge the power transformers for use with your regulator 
> board.
> 
> Jay
> 
> 
> ----- Original Message ----- 
> From: "Andy - KU4XR" <ku4xr at yahoo.com>
> To: " European & UK) and MedFer bandsDiscussion of the Lowfer (US" <lowfer at mailman.qth.net>; 
> "Part-15 Yahoo" <part15 at yahoogroups.com>
> Sent: Saturday, April 17, 2010 11:32 PM
> Subject: Re: [Lowfer] A power supply head scratcher
> 
> 
> Hi Gentlemen:
> 
> As usual, a wrong choice of words on my part. I tied the positve wire
> of one wart to the negative wire of the other one. The remaining
> positive , and negative wires went to the circuit. At this point, I am
> just about ready to sling these thing as far into the pond next door
> as I can throw them. In all my years. I have never had a power supply
> to do such crazy things. BUT !!! I must state that I have never tried
> to use these stinkin little SMPS wall warts either. Always used analog
> supplies before. But you don't find 30+ volts DC in an off the shelf
> store bought power supply. The best thing I could do now is to just
> build myself a good analog supply with a 24 volt transformer. That
> should approach the 30 volt output when filtered, and then run it into
> my adjustable regulator board to get the 25 volts I need, or very close
> to it at least.
> 
> To note for the record: Thanks to everyone for the tips offered.
> I have tried all of them. .1 caps everywhere I could fit one, reverse
> biased diodes, load resistors across the output. even tried the
> paralled diode, resistor, capacitor trick. Nothing will stop the spikes
> from killing the beacon. *** There is a better than not chance that the
> wall wart is bad. Could be why I found it in a junk box of parts at the
> local flea market.
> 
> 
> Andy - KU4XR - EM75xr - Friendsville, TN. USA
> LOWfer Beacon " XR " @ 185.29875 KHz ( QRSS-60 )
> Coordinates: N: 35º 43' 54" - W: 84º 3' 16"
> http://www.myspace.com/beaconxr
> http://webpages.charter.net/ku4xr/
> 
> 
> --- On Sat, 4/17/10, Jordan <outposter30 at shaw.ca> wrote:
> 
> > From: Jordan <outposter30 at shaw.ca>
> > Subject: Re: [Lowfer] A power supply head scratcher
> > To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands" <lowfer at mailman.qth.net>
> > Date: Saturday, April 17, 2010, 8:47 PM
> > You're going to start a fire....
> >
> >
> > ----- Original Message ----- 
> > From: "Bill Ashlock" <ashlockw at hotmail.com>
> > To: <lowfer at mailman.qth.net>
> > Sent: Saturday, April 17, 2010 5:27 PM
> > Subject: Re: [Lowfer] A power supply head scratcher
> >
> >
> >
> > "I simply connected them 10 volt positive open, and the
> > negative
> > connected to the 24 volt positive, with the negative
> > open."
> >
> > Hi Andy,
> >
> > Am I correct in my thinking that you have not connected
> > anything to one of
> > the two output wires of each wallwart? If so, I don't
> > understand why this
> > works at all unless there is some kind of sneak path to the
> > neutral line in
> > each power supply. Why not connect them in series as though
> > they are
> > batteries? These wallwarts have a power transformer that
> > should isolate the
> > DC output from their AC power inputs and this DC should
> > float relative to
> > anything else.
> >
> > Bill
> >
> > > Date: Fri, 16 Apr 2010 20:38:58 -0700
> > > From: ku4xr at yahoo.com
> > > To: lowfer at mailman.qth.net;
> > part15 at yahoogroups.com
> > > Subject: [Lowfer] A power supply head scratcher
> > >
> > > First, Thanks for all the responses to the antenna
> > insulator question.
> > > J.B. had the one i'd never of thought up, The broken
> > pole vault pole.
> > >
> > > I do have a head scratcher here. To get around 35
> > volts DC, I have
> > > connected 2 wallwarts in series. One is a 10 volt, and
> > the other,
> > > a 24 volt. Connected together I have 37 volts DC. ***
> > This is the first
> > > time I have ever tried this method before, so I have
> > no previous
> > > experience to go by. I simply connected them 10 volt
> > positive open, and
> > > the negative connected to the 24 volt positive, with
> > the negative open.
> > > The problem I'm having is that everytime something in
> > the house turns
> > > OFF, it kicks off the beacon....hmmmm. AC goes off,
> > and so does the
> > > beacon, fan in the room goes off, beacon does too.
> > connect the HF ant.
> > > to the radio and it kicks the beacon off. I have
> > filtered the hound out
> > > of it. But can't stop this problem. It seems to be
> > coming in on the
> > > ground line. These 2 wallwarts were 2 pronged plugs,
> > and would not work
> > > the circuit until I connected a 3 prong plug with the
> > ground wire going
> > > to the DC negative wire. The warts are SMPS. Even
> > though I have the
> > > voltage I want, something is amiss. It is getting
> > spiked somehow.
> > > Has anyone tried this before, and had a similar
> > experience ?? If so,
> > > were you able to fix it, and how did you do it ?? I
> > may have something
> > > wired the wrong way, or maybe missing a capacitor
> > where one should be.
> > > I don't have a schematic for a circuit like this, and
> > can't find one
> > > on the net. I'm wondering if I have a floating ground
> > issue between the
> > > 2 wallwarts.
> > > Any input will be appreciated, and thanks for your
> > time.
> > >
> > > 73 everyone :::
> > >
> > >
> > > Andy - KU4XR - EM75xr - Friendsville, TN. USA
> > > LOWfer Beacon " XR " @ 185.29875 KHz ( QRSS-60 )
> > > Coordinates: N: 35º 43' 54" - W:
> > 84º 3' 16"
> > > http://www.myspace.com/beaconxr
> > > http://webpages.charter.net/ku4xr/
> > >
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