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[TenTec] Orion Display and Power Distribution Board

To: tentec@contesting.com
Subject: [TenTec] Orion Display and Power Distribution Board
From: Heinz Dietmar Karl <h-d.karl@t-online.de>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Wed, 12 Jan 2011 22:32:44 +0100
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
Hallo Orion users,
2 weeks ago I`ve got an Orion1. It was announced to be full ok.
But as I switched it on , I saw the display was a little dark in the 
upper left corner
and was flickering during transmission.
After a discussion with the former owner i was looking for the reason.

After studying the schematics and some measurements I found the reason .
The +5volts- voltage on the power distribution board A9 is unstable.
During transmission and by changing the power voltage e.g. the 
5V-voltage alternates between 5 and 4,4 volts.

At first I tried to get an new board . But it was not on stock at Ten Tec.
Then I found this forum here and could learn what has happend before 
with some failures around the unstable 5 volts.

But changing the recommended board-capacitors brought no better results..
Then I saw a difference between the board schematic and the circuitry on 
my A9 board:
On my board the upper PNP -transistor was not the original type TO220P 
NTE 378.
Ten Tec had used -how long?- another type BD246C .

Because this one is a TO3P Type and not fittable onto the bord , it was 
mounted very carefully-like production people do it-
via 8cm long wires beside the A9 board on the al -case.

I am very sure this outsourced transistor has worked in my Orion since 
it has left the production.
( Serial Nr. 10C 10584  in 2005)

I ordered- over night- the the original NTE 378 from a semiconductor 
dristributor, placed it next morning
within 15 minutes directly onto the board and it worked perfectly.

see http://www.qrz.com/db/DJ8LX

The +5volts are stable under all conditions .
Now I am very happy with my Orion.

best 73
Heinz , DJ8LX

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