Re: smb plug?

Alan Melia

Martin check you have actually got a three wire earthed lead suppled with the desktop. I have found leads with IEC con and metal Earth pins but onlt L and N connected through. If this is the case your laptop may even be worse and they usually float. If I am plugging things into a PC I like to have everything firmly grounded on the chassis. There can be 350Vac as measuredon a high impedance DMM. This is sometimes enough to take out in interface device.

----- Original Message -----
Sent: Friday, January 17, 2020 11:16 PM
Subject: Re: [UKMicrowaves] smb plug?

I did not take the original socket off the board. The input one can have the SMA 'plugged' into it and just the four corner legs soldered. The output came with the 'barrel' connector and here again I just 'plugged' the SMA into one end and soldered.
Today I used the jumper leads to plug the power into the power sockets and powered the amp up (with dummy load) It takes around 2 Amps but I could not get a signal into it as when I connected the Pluto to it the Pluto disconnected from the computer!!!
I measured a small voltage between the outer SMA on the pluto and the negative lead (which is earthed at the PSU) with the Pluto connected to my computer. There must be some sort of earthing problem in my system! Tomorrow I will try again and could use a laptop to drive the Pluto to avoid the earth problem. I may have a clue here to other problems I have had with connecting to the Pluto......

See how the back of the SMA is like a plug and the four legs are used to solder it down.

Martin G8LCE

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