Re: bayou jumper no tx


Richard Dickerson
 

Mine failed to work because my old eyes allowed me to swap capacitors. I ended up using a USB microscope to read them, swap two and it worked great.

Richard WF2F

On Apr 26, 2018, at 12:34, n5ib_2 <n5ib@...> wrote:

Hi Ken,

We've had some reports of the Tx section of the Bayou Jumper giving troubles, and in at least a few cases the trail led to the final transistor Q4 (IRF-510).
It appears that certain "flavors" of the IRF-510 present too great a load to the oscillator stage (Q5) and prevent it from oscillating.

I've tested samples froma few different batches, and at this point I'm pretty sure that IRF-510 transistors that are marked ""Y64K AP" work reasonably well at Q4, but those marked "618 P 77 WS" would kill the oscillator. Some new IRF-510s bought from Mouser (Mouser #844-IRF510PBF, factory marked "N77K BJ") also worked.

You can check if the Q5 oscillator works with Q4 out of the circuit, but quits when Q4 is connected.

Doesn't matter what sort of IRF-510 goes at Q6 - that's just DC service.

N5IB




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