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Re: Re: Deaf DEM 2400-144RX

Several years ago I was building DEM's previous-generation downconvertor,
and I was testing each stage as I built it.  But parts kept failing.

I found the reason was this:  I had the board connected a receiver that
was grounded to an outside ground, and my soldering iron was
grounded at the 120v grounded outlet there it was plugged in.
Between these two "grounds", there was about 30 volts AC!
(This was an apartment building, where I had no knowledge or
control of the wiring.)  

So whenever I soldered something while the board was plugged into the
test setup, I blew out another MMIC.

My advice is to always have a grounding connection directly
between the soldering iron and the circuit board.  I use a wire with
an alligator clip on each end.


At 10:35 PM 10/16/01 , you wrote:
>re: shorted MMIC holes
>The other working theory is that I may have fried the gate oxide of the FET
>with static. Someone is sending me some anti-static procedures to go through
>(ground strap, on me, on the soldering iron, I would suppose) that worked
>for them. I have a replacement FET coming in the mail.

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