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Author Topic: Astron SS-25 shutting down  (Read 683 times)
K3GHH
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Posts: 55




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« on: November 07, 2017, 09:00:36 AM »

This little switching supply suddenly shut down a couple of days ago, but worked later. Same thing happened yesterday.
Anyone familiar with this? I notice the fan is not running, but maybe that's OK.
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KC9NVP
Member

Posts: 204




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« Reply #1 on: November 08, 2017, 05:39:33 AM »

Need some more information:
1) what is connected to the output of the power supply?
2) have you measured the output voltage and current before, during the shut down?
3) what is the voltage and current requirement of the load connected to the power supply?
4) does the supply feel more than warm when this happens?

It is possible that the fan is not turning on when it should and the supply is overheating and going into shutdown, but we need more information in order to direct you to a possible solution.


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K8AXW
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Posts: 6310




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« Reply #2 on: November 08, 2017, 10:02:28 AM »

I second NVP.  To me it sounds like a heat related problem, either from overload to the fan not operating.

You might try taking the lid off and see if it stays on.  You could also check for heat on the large transistors and or heatsink by touching them after operating some.

HOWEVER if you do this, be VERY careful because high voltages lurk in a SS power supply!!
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K3GHH
Member

Posts: 55




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« Reply #3 on: November 15, 2017, 07:41:07 AM »

Thanks, guys. The problem has not recurred since I posted it here, but here's some of the info. I suspected heat too but it doesn't feel hot and has just been sitting on a shelf where it's always been. There is plenty of air space all around it.

Output: a MFJ distribution panel with its own voltmeter; the only device plugged in was the Powerpole to the Orion 2 transceiver
Voltage: About 14 before, 0 after, and couldn't get it during the (instantaneous) shutdown
Rqmts: Don't know --- Orion 2 just being used for receive (I was just listening to one of the ham bands as background, when it suddenly shut off)
Warm? Nope

I'm curious about the fan too, and will look into it probably after the holiday.

Thanks again.
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K8AXW
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Posts: 6310




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« Reply #4 on: November 15, 2017, 09:50:17 AM »

Not to insult your intelligence, but I must ask.  Is the power supply actually shutting down......panel indicator light off? 

Did you check the voltage at the power supply terminals when it went down? 
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N4UE
Member

Posts: 697




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« Reply #5 on: November 15, 2017, 12:44:41 PM »

A lot of the power supplies in older, large PCs had speed sensing/feedback in the fan circuit.

I had a local PC shop giving me the failed PSs. Typically, dust had the fan stalled, this in turn, turned off the PS. The number of PSs they replaced was staggering. I finally told them, "thank you, but no more".

So, just check your fan to ensure it's free turning and not stopping.

ron
N4UE
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