Re: €44.76 EUR puff of smoke


From: Robin Szemeti - G1YFG
Date: Wed, 22 Dec 2021 06:53:28 PST

Only €45 worth?  Amateur!


My most expensive mistake so far (to the tune of probably 1000 times the above) was connecting a ST Keltek SatCom TWTA to a 230V supply..  Those are 115V only machines!

No smoke, but the two 6 inch fans on the back that would usually take some 5 seconds to get up to speed, did a naught to full chat in an instant!  (AC powered fans.)

Utterly destroyed the primary side of the PSU though, a direct-off-line regulating inverter type.

We were a very "young" company back then, & as the book value of that unit was at least twice my salary at that time, I offered to "close the door on my way out" but the offer was not accepted...

The eventual repair once back at the US factory was done under warranty in the end.  As after the PSU primary side was repaired, a production fault in the TWT potted HV PSU secondary was found (and fixed) that was the cause of the original "fault" we had it in for repair for from the customer.  (We also "won" a spare TWT in the process too!  That got the same customer out of a hole some time later, when another unit had a genuine TWT fault.)

One learns stuff over time...


Dave G8KBV.

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