Greetings to all,
I have just finished evaluating two types of hi-voltage switching
transistors to replace the original, inadequate, device in the factory
Ameritron QSK-5 and QSK-5PC units.
Originally I used 2SC5305 transistors. These worked find for a
reverse bias of 700 to 800 volts. Unfortunately, I have not been able to
locate a current source for these devices. Thus the search for another
replacement.
The 2SC5589 is a suitable replacement, and will allow raising the
reverse bias to well over 1,000 volts. However, this devise is quite large
and is not so easy to adapt to the board.
The BU508A is the transistor I have settled on. It has basically
the save ratings at the 2SC5589, but is about 1/3 smaller. It's lead
spacing wider than that of the original transistor, but the leads,
themselves, are the same as a standard T0-220. These leads are easily bent
to fit into board and, due to its smaller size, it fits quite nicely.
I strongly recommend that, if you have to replace the switching
transistors in your QSK-5, for what ever reason, that you install standard
T0-220 sockets to the board. These sockets are readily available and will
really save wear and tear on the board.
73 de Lon, K5JV
Lon W. Cottingham
1110 Golden Bear Ln.
Kingwood, TX 77339
281-358-4207
281-795-1335 Cell
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