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eHam Forums => Misc => Topic started by: N5GZH on October 12, 2013, 07:33:36 PM



Title: probably nothing but--
Post by: N5GZH on October 12, 2013, 07:33:36 PM
Still getting my station set up with mostly new(ish) equipment after being off the air for many years.   I am using a new Astron RS-35A power supply,  linear design. 

I have not yet powered up the transceiver, but I just turned the PS on for a (no load) voltage check.   Output was 13.8 VDC on my multimeter.  FB.  It's just that the power supply made a fairly loud buzzing noise for maybe a half second after being switched on.  This is the second time I've even had it plugged in and turned on.   It didn't make a sound the first time.

So I'm guessing this has something to do with big capacitors charging up through the transformer.  Questions, please:  Is this within the parameters of  'normal' ?   As long as the multimeter is reading within specs on the DC scale, should I be concerned about what it might be feeding into my Kenwood TS-590 ? 

 



Title: RE: probably nothing but--
Post by: NO2A on October 12, 2013, 08:40:01 PM
I have the same power supply. Most of them do that. Nothing to worry about.


Title: RE: probably nothing but--
Post by: N5GZH on October 13, 2013, 12:53:27 AM
Thanks !


Title: RE: probably nothing but--
Post by: N6AJR on October 14, 2013, 11:36:49 AM
OH no, the infamous buzz before death and destruction of the entire known universe.  Good by doctor WHO, so long Flash. beam me up scotty before this world explodes from the buzz. 3, 2, 1,  boom.


Just kidding, this is quite normal, usuall either the filter caps charging or vibration in the steel transformer windings.

not a problem


Title: RE: probably nothing but--
Post by: KE4JOY on October 14, 2013, 01:55:50 PM
My Ameritron liner ps sometimes "bumps" sometimes not. I think it has to do with the sine wave crossing at the instant its turned on. But yea 'normal'.


Title: RE: probably nothing but--
Post by: AG6WT on October 15, 2013, 07:44:06 AM
Have have that model and mine does that too. From what I've read this is normal for this model.


Title: RE: probably nothing but--
Post by: N5GZH on October 15, 2013, 09:34:17 AM
Thanks for all the good info.  This is pretty trivial stuff.  Just that the high cost $$ of equipment is making me extra careful.   

If the neighbors tell me their house lights dim at power up, then maybe it's time to get  concerned.      :-\


Title: RE: probably nothing but--
Post by: KE4JOY on October 15, 2013, 01:43:53 PM
Lights in my shack dim briefly, there is a lot of inrush but it only lasts a half cycle or so. Breakers never even 'see' it.


Title: RE: probably nothing but--
Post by: AA4PB on October 15, 2013, 02:07:43 PM
How does the current get to the power supply if it doesn't go through the breakers  ;)


Title: RE: probably nothing but--
Post by: KH6AQ on October 15, 2013, 05:23:58 PM
I suspect the buzzing is the transformer going through the flux doubling stage. It's interesting to watch the primary current on a transformer at power-up take dozens of cycles before the core settles to the center of the B-H curve.


Title: RE: probably nothing but--
Post by: G3RZP on October 15, 2013, 05:29:17 PM
WX7G

Does the extra Exam require knowledge about BH curves?


Title: RE: probably nothing but--
Post by: KC8Y on October 16, 2013, 07:25:53 AM
I've used my Astron RS-35A for about 23-years.  I use it, now, on my IC-7410 xcvr; before that, used it on my TS-440S xcvr, and never had any problems at any time with any rigs power supply.

Also have the Astron RS-20A, which I use on the IC-V8000 for 2-meters.  No problems with that either.

Astron Company seems to design & build their power supplies well  :)


Ken KC8Y


Title: RE: probably nothing but--
Post by: KE4JOY on October 16, 2013, 11:54:18 AM
How does the current get to the power supply if it doesn't go through the breakers  ;)


Breaker never sees the current spike its so fast.. wise guy :D


Title: RE: probably nothing but--
Post by: KD0REQ on October 19, 2013, 03:20:51 PM
breakers (and fuses) need to heat up before they trip.  they see the spike, but if it doesn't heat up the trigger enough, no biggie.

inductive loads can cause breaker pop, this is why they make motor-rated breakers.  if you have to ask, you can't afford it, and you won't see them at the LowDepotNardsOSH.

this is also why they make soft-start kits, and also PTR surgistors that look like HV disk capacitors.  they get way hot in use.


Title: RE: probably nothing but--
Post by: W5LZ on October 19, 2013, 05:49:10 PM
G3RZP,
There may be a bit of confusion with that 'B' and 'H' thingy and the Extra exam.  There are different meanings for that depending on where you are.  For instance, here in the south, it means Beans and Ham.  To the best of my memory, there were no cooking questions on the Extra test...
 - 'Doc