On Wed, 2007-09-12 at 20:55 +0200, Vicenà Llario wrote:
> To the Ten Tec list members
>
> Last weekend I was troubleshooting the TX side of my 1208 transverter
> and found that the bias transistor Q14 was faulty. I tried to find a
> replacement in the 2 main electronic components shops in my area but I
> did not manage to find it. It seems that the original MPSW01 NPN
> transistor is not so common and also it is out of production. I wonder
> if perhaps some member of the list may have one of those transistors and
> would be willing to part with it. I would obviously pay the component as
> well as the shipping costs to Barcelona, Spain. While looking for an
> alternative I found that the Fairchild TN2219A has exactly the same
> features as the original used in the transverter. If nobody has a
> replacement transistor in the junk box I would appreciate advice on where
> to get one.
>
> Many thanks in advance for your kind help and best 72
>
> VicenÃ, EA3ADV
If a TN2219A works, the transistor isn't critical. Its a 200 ma NPN with
maybe half a watt dissipation. While the device may do (at least the
metal cased 2N2219) half a watt of RF up to 50 MHz, this doesn't sound
like a RF transistor but just a switching transistor. Same chip as a
2N2222, but a bigger case (at least for the equivalent 2N2219).
The main feature of the MPSW01 was probably cost.
The NTE cross, NTE-128P, is a fat TO-92 package with a metal heatsink
fin out the top, with pins E B C left to right. Different from some
makers that put the collector in the middle in the plastic in line
package. The 128P is a bit sturdier than a 2N2219, but not much. 2N3904,
or 2N4104, fairly common audio transistors ought to work too.
--
73, Jerry, K0CQ,
All content copyright Dr. Gerald N. Johnson, electrical engineer
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