[TenTec] Orion Display and Power Distribution Board

[Dr. Gerald N. Johnson]

NTE is a replacement line, typically more expensive than original 2N 
parts. The BD246 part is not a typical US part, though its possible, but 
that's more a European part number, unlikely to be stocked at US 
distributors.

But the A9 schematic I've downloaded shows a NTE377 and a NTE378.

73, Jerry, K0CQ

On 1/12/2011 3:32 PM, Heinz Dietmar Karl wrote:
> 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
>
>
>