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Author Topic: Need power supply advice for my IC-7000  (Read 5108 times)
CHRISDX
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Posts: 244




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« on: November 22, 2010, 10:41:48 PM »

hi all,

boy do I feel dumb. my radio was seeming down on output power, so I sent it in for service. the excellent matt adrian at SAR Tech Services found nothing wrong and did a factory update and sent it back. when i spoke with him, he suggested checking my power supply voltage while transmitting, and said the 7000 likes good voltage. sure enough it drops to 12.4v under full load.

my supply is a Samlex SEC 1223. once when I mentioned that unit to another ham during a qso, he said he had one of those and threw it away. i didnt know what he meant.

at any rate, I would like a more robust power supply and preferably one that I can adjust the volts with. matt did mention what input volts my radio likes, I just emailed him to ask again.

also, i just poked through the forums and reviews, and noise is an issue too. so i guess i need a power supply that is strong, steady, and quiet of rf as well.

regards,
chris
KB1SNJ



« Last Edit: November 22, 2010, 10:50:40 PM by Chris P KB1SNJ » Logged
WB6DGN
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Posts: 606




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« Reply #1 on: November 23, 2010, 01:26:25 AM »

Not the newest kid on the block but, in my opinion, one of the most reliable; the Astron linear power supplies.  For your rig, probably the RS-35A would be the best choice.  It's stable, clean and virtually ripple free and has been around long enough to get the bugs worked out.  Being a linear supply, it's heavy and less efficient than a switcher but it's quieter than any switcher and, in my opinion, far more reliable.  It's available with and without meters and with or without variable voltage and current limit controls.  My opinion, for a rig power supply, who needs either one; for a bench supply they're handy but for the rig, there's an internal pot to adjust the output to anywhere between about 9 volts and 15 volts.  Set it once and forget it.  Also, less chance of it accidentally getting turned up too high and stressing the radio.  They're reasonably priced, not the cheapest, but as the saying goes...you get what you pay for.  If you just MUST have the meters, choose an RS-35M and if you want the external variable voltage and current, choose the VS-35M.  Also a rack mount version available (in my opinion, way overpriced), the RM-35 (A or M).  You'll have that supply long after you trade the radio for a newer model.
Tom
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AD5X
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Posts: 1429




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« Reply #2 on: November 23, 2010, 04:18:32 AM »

I had a Samlex 1223 for a bunch of years and it worked great.  I now use a Samlex 1235 as I have a lot more 12V accessories in my shack.  If the output voltage is dropping, the first thing I'd do is measure the voltage right at the output of the power supply under load.  My guess is that it doesn't move much (mine only dropped about 0.1-0.2VDC under load).  If that is the case, check the voltage right at the transceiver (I bet that is where you are looking now using the IC-7000 voltmeter, but you should check it at the radio input with a voltmeter).  I bet the problem is with the DC interconnect cable and connectors.

Phil - AD5X
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CHRISDX
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Posts: 244




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« Reply #3 on: November 23, 2010, 06:50:24 AM »

ok thats good advice guys.  I was in fact using a DMM at the radio, so now I will look at volts coming right out of the ps.  if there is an issue with the unit, my review-reading already pointed to the astron, I hear the same things - that users have turned them on and not touched them for years on end.

chris
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N1LO
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« Reply #4 on: November 23, 2010, 07:14:39 AM »

I chose the Daiwa SS-330W several years ago and have been delighted with it. Extremely small, light, quiet, fully metered, and adjustable.

http://www.eham.net/reviews/detail/2137

- - · · ·  M A R K · N 1 L O · · · - -
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KZ1X
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Posts: 3229




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« Reply #5 on: November 23, 2010, 07:29:54 AM »

As others have pointed out, you likely have an I^2R problem, not a power supply problem.

Please describe, in exacting detail, every element between the power supply and the radio.  For example:

"I used the factory wire harness.  It connects to the back of the power supply by the two connectors Samlex provides, which are 5-way binding posts and they are of plated steel.  I inserted the tinned ends of the Icom wire into the side port hole and tightened the outer grip to 6 inch pounds.  There are 11 feet of the wire Icom provides, approximately a 10AWG, and next in line are two series fuse holders, each with a friction clip holding an AGC size ..."

Et cetera.  I provide this example for you to follow since every single piece of information helps people who aren't there to figure out what, if anything, is awry.
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WB2EOD
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Posts: 218




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« Reply #6 on: November 23, 2010, 08:03:20 AM »

No load voltage should be around 13.8. Full load voltage should be around 13.5. At these current ratings, those few tenths of a volt can be significant.  
You didn't mention (or at least I didn't read it) whether you are measuring voltage at the power supply or the radio.  
You need measure the full load voltage AT THE RADIO to eliminate the power cable as the source of the voltage drop.  
You also need run the full load test while transmitting a straight carrier into a suitably rated dummy load. This will eliminate the possibility of stray RF "fooling" the power supply    

Let's assume for the moment that the power cable is NOT the source of the voltage drop, this leaves 3 possible answers.
1. Your power supply is under rated.  
The power supply for a standard 100 watt HF rig should be rated for at least 30 AMPS CONTINUOUS  
2. Your power supply is defective
3. Stray RF from the radio is "fooling" the power supply.  
This is caused by poor SWR or perhaps a loose antenna connection.  I have had this happen to me.  A crimp-on coax connector pulled loose and caused enough stray RF to shut down the power supply.  (I don't use the crimp-on connectors any more!)  

Hope this helps
73
WB2EOD


 

  
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WA3SKN
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Posts: 5453




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« Reply #7 on: November 23, 2010, 08:40:47 AM »

The SEC 1223 is rated at 23 amps SURGE... providing about 18 amps continous... and you should be using one rated at least 22 amps continous for that radio, so it is dropping voltage and losing regulation.  You really should be using the SEC 1235 for your radio's current draw.
1. You can get a larger power supply (SEC 1235M or Astron R35). or...
2. You can parallel a 12 volt battery to supply the extra current. or...
3. You can lower your transmitter's output power so you do not draw too much current.
You are not alone in this mistake, many have misjudged current requirements.
73s.

-Mike.
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AD5X
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Posts: 1429




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« Reply #8 on: November 23, 2010, 09:12:48 AM »

According to the Samlex website, the SEC 1223 is rated at 23 amps continuous.

Phil - AD5X
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WA3SKN
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« Reply #9 on: November 23, 2010, 12:16:20 PM »

I stand corrected!
The SEC1223 IS rated at 23 amps continous, but with only a 24 amp surge.
The SEC1235 is rated at 30 amps continous with a 35 amp surge.
And the Astron RS35M is rated at a more conservative 25 amps continous but 35 amp surge. (and a fine reputation!)
With such a narrow range, I would be interested in measuring the output regulation at full current draw, though.

-Mike.
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CHRISDX
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Posts: 244




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« Reply #10 on: November 23, 2010, 01:57:23 PM »

ok now that I am back from work to my real world, I pulled the Samlex outta my cabinet below and put it up top and took a craftsman DMM to it and with no load it is around the proper 13.8v . 

The Craftsman was giving weird readings like 2v at the PS when keying up (low battery?), so I grabbed ANOTHER DMM and did isolate the problem.  The ICOM fuse holders have poor connections. The volts at the Radio varied from 11.5 to 13.x when keying up, and the fuse holder is warm.

This reminds me that Matt Adrian said this was something to check, and I had totally forgotten that.

So, the voltage question seems to be answered. Now two things:

1) what to do about the inline fuse holder issue since I do need fuses
2) some of the reviews mentioned the Samlex switching ps makes noise on HF. I'm kinda new ham so not sure how I would know that, and does the Astron linear PS resolve that (if it's even an issue for me)

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AD5X
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Posts: 1429




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« Reply #11 on: November 23, 2010, 03:16:28 PM »

The older SEC1223 had RF spurious outputs.  Samlex added additional filtering later on to resolve this, and I believe someone also published fixes for this.  My SEC1223 and my SEC1235 are extremely RF quiet.  If the pc board in your 1223 uses some surface mount parts, then you definately have the additional filtering.  However, Samlex did start putting in additional filtering when they were still using thru-hole components.  If you have an RF noise problem, you'll find discrete tones about every 50 khz or so across the lower frequency bands.  I did make measurements on my SEC1235.  Info is in the "Product Reviews" section of my website at www.ad5x.com.

I never have liked those cheap in-line cartridge fuse holders.  The clips seem to loosen with time.  I always snip them out and replace them with automotive blade fuse holders.

Phil - AD5X
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KZ1X
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Posts: 3229




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« Reply #12 on: November 23, 2010, 03:32:40 PM »

I'm glad to see you made these checks.  

Rather than tell you what was wrong (this is a well-known design problem) you found out for yourself - and have turned the situation into a learning experience.

The fix is to replace the factory fuse setup with one that offers VERY low resistance.  Remember:  even a tiny fraction of an ohm is critical here.

Math example:  at 20+ amps draw [P=I^2R]  ... 20A x 20A = 400, times even one-twentieth of an ohm ... still is 20 watts!

This is the kind of thing you want:

http://www.powerwerx.com/fuse-holders-fuses/atc-inline-fuse-holder-10-gauge.html and of course other examples abound.  Splicing in the fuse holder is a key part of the success.  Sadly, the rig's power connector will remain another resistance point but that's how it goes, the worst one is the fuse holder.

Regarding the 'birdies' the supply puts out ... my older Samlex 1223 did emit noises in the broadcast band and on 160, but since my antenna were generally far from the rig I only heard some conducted signals which I was able to choke out.  Newer units are far quieter RF wise.  But if your antennas are too close to your shack, you'll pick up the supply noise, if any, as well as other junque, either way.  Much above 4 MHz and I doubt the supply will bother you much.
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N0AZZ
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Posts: 241




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« Reply #13 on: November 25, 2010, 06:35:51 AM »

I have used the SEC-1223 for 3 1/2 yrs with my IC-7000 full power no noise in fact I now have 2 a SEC-1235M also that now powers the 7000 plus 4 other items. The 1223 now powers a IC-2820 and a FT-8800.

QST did a piece on switching power supplies a few months back and the Samlex PS were top rated for price point.
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VA7CPC
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Posts: 2372




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« Reply #14 on: November 25, 2010, 10:08:50 PM »

From KZ1X:
Quote
This is the kind of thing you want:

http://www.powerwerx.com/fuse-holders-fuses/atc-inline-fuse-holder-10-gauge.html and of course other examples abound.  Splicing in the fuse holder is a key part of the success.  Sadly, the rig's power connector will remain another resistance point but that's how it goes, the worst one is the fuse holder.

+1. 

Glass in-line fuses are a frequent source of trouble in boats -- lots of chances for corrosion, and low spring pressure on the contacts.  The ATC (automotive) fuses will do better, they have a more solid connection.

I would put a dab of grease ("dielectric grease" is good) or a bit of WD40 on the fuse contacts (and the rig's power cable contacts) to stop corrosion.

You did a good debugging job.

                   Charles
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