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[TenTec] OMNI D ser B low power output--still no joy

To: tentec@contesting.com
Subject: [TenTec] OMNI D ser B low power output--still no joy
From: scottsheppard@videotron.ca
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sat, 11 Feb 2012 11:02:45 -0500
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>

I am still not getting much power out of the omni...so far I have disconnected 
the input to the PA and measured direct out from the Low Level Driver 
(LLD)...almost nothing to measure even on the 5 watt scale...yet, when going 
thru the PA and adjusting the final PA bias on the control board, I can get 
close to 4 watts which seems to indicate the PA is taking the very very low 
input and bringing it up to that level...problem is I am drawing about 8 amps 
to get 4 watts!

I tried replacing the mrf476 on the LLD with an equiv 2166  and no diff...I 
also replaced the two other transistors on the LLD with a 2n3503 (or 
similar)...no difference.

I even went further back to the OT board (the stage before the LLD) and swapped 
out those transistors...no change at all.

When I transmit into a dummy load for a few seconds the transistors on the low 
level driver do get warm, yet I again, cant measure anything really from the 
LLD output...

Any suggestions? I am thinking perhaps switching out the diodes on the LLD next 
but I am really taking a shotgun approach here. As always, your collective 
wisdom/comments are welcome...If TEN-TEC has time perhaps they can shed some 
light as well next week. 

scott va3ied

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