[hpsdr] How do you switch power to Atlas

[Chris Smith]

Mark

You are right, I was referring to pin 14 on the ATX connector. I was relying on my memory - a very dangerous thing to do at my age - and had quite forgotten about the disable function.

Cheers & 73

Chris G4NUX

On 4 Dec 2011, at 00:06, Mark Leone wrote:

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> On 12/3/11 6:09 PM, Chris Smith wrote:
>> Mark
>> 
>> I'm pretty certain that pulling pin 4 low on a standard ATX PSU has the effect of powering up the PSU. If you're using the LPU then pin 4 will have no effect, so a jumper from T7 to T8 won't have any effect either.
> Thanks Chris. I think you're referring to pin 14 on the ATX connector, and you're right that it has no effect on LPU. After posting, I noticed a comment on the LPU Wiki page that it ignores the ATX power-on signal and is always on. I was referring to pin 4 of the voltage regulators, not the ATX connector. That's a voltage disable signal, which turns the output off if it goes below 0.8 volts. In the LPU design, the Vdis signal is tied to the Vin signal, which prevents it being used as a power on/off control, short of modifying the PCB, which I don't want to do.
> 
> On 12/3/11 6:21 PM, n3evl wrote:
>> FWIW, I'm just today in the process of replacing the LPU with a PicoPSU and discovered that while LPU does not care about T7 T8, the PicoPSU certainly does.  Fortunately I already had a switch wired across T7 T8 since, a while back, I'd used Atlas with a conventional PC PSU. 
> 
> Thanks for that Pete. I'll look into switching to PicoPSU. It's my own fault for not reading the LPU Wiki page more carefully, but I need a PSU that works with a power switch. And it's not just because I already drilled a hole in Pandora. I have a 100 watt transceiver right next to my HPSDR, powered from the same power panel, with just a coax switch between the two transceivers and the antenna. So I really don't want to have either of them powered up when the other one is transmitting; and removing power pole connectors is not convenient.
> 
> Mark - K4XML
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