Topband: Receivers, Noise Blankers and Key Clicks

[Steve Lawrence]

On Feb 4, 2004, at 8:25 AM, Barry N1EU wrote:

I'll let Mike answer, but I was assuming he was referring to the 
original FT-1000, NOT the MP/MkV.  I've heard many FT-1000(D) 
transmitters on the air that have been burdened by noisy sidebands, and 
sometimes low level discreet spurs.

73,
Barry N1EU

*************************************************

In October 2002 I posted a message on the Yaesu reflector about a buzz 
/ phase noise sound on receive in my FT1000D at turn-on on 28020 and 
other 10m frequencies and also to a lesser extent on 12m. The fix I 
recommended was to tighten the circuit board screws on the filter board 
accessible by removing the top cover and then lifting the shield up 
from the board for access. Unfortunately, the problem returned shortly 
after that posting. A firm fist on the right side and to the rear of 
the radio would just about clear the problem until the AC power was 
cycled.

I subsequently found the permanent fix and posted it in February 2003. 
After removing the top and bottom covers, I found that the screws 
holding the RF board and the Sub RX board — both on the right side of 
the radio where my fist had been effective — were simply sitting in 
place with essentially no torque. I tightened these screws and any 
others, top and bottom that I could easily see. Although tempted, I 
left the screws holding down the PA transistors alone!

The problem has not returned in the past year. After nine years, screws 
loosened or were never tight to begin with or both.

CAUTION: Disconnect all power when attempting this. YMMV.

I post it here as part of the discussion because poor internal 
grounding, in my case from loose screws, can contribute to a variety of 
problems including noise.

73, Steve WB6RSE