eHam Forums => RFI / EMI => Topic started by: W0GXA on January 03, 2013, 07:48:22 PM

Title: Autek QF-1
Post by: W0GXA on January 03, 2013, 07:48:22 PM
Anyone on here have a problem with RF getting into an Autek QF-1, rectifying and causing the audio out to buzz when it's key down?

I've added ferrite to both the power and audio inputs but it hasn't cured it yet on 10m...  Looking for new ideas.

73, Bob

Title: RE: Autek QF-1
Post by: W3HKK on February 14, 2013, 06:54:26 AM
I had a QF-1 back in the 70s.  Nice piece of gear.  One day  my tower took a close lightning strike..or maybe even a hit.  The shack was next to  the washer and drier. ( Later when we moved, and the washer/drier were  unhooked and  put on the truck, I saw both parallel faces  on the adjacent sides had  a giant black discharge arc mark on it  with much of the porcelan blown off the metal sides. ) 

But right after the strike, my QF-1 stopped working.  I looked inside and saw both ac bypass disk ceramic caps  had melted off at all four leads, and the center of the caps had black holes in them.

The Point:  Try  testing  or replacing the bypass caps  to ground, located across both sides of  the ac line  where it enters  the chassis.   I think mine were .05 mf 500 v rated.  or maybe 1000 v

Title: RE: Autek QF-1
Post by: WB6BYU on February 14, 2013, 02:04:21 PM
Bypass capacitors in the input/output audio leads?