Ron,
I hope you have adequate heat sinking on the IRF510. If it is still getting
hot, there may be three reasons for it:
1. The IRF510 is oscillating. If you have an oscilloscope, can you check if
the waveform is clean? If not, this is where you have to work.
2. it is drawing more current than required. How much is the idling
current? It should be less than 100mA. This is the current that the IRF510
will draw when you press the transmit button without connecting the mic.
3. the IRF510 is not properly matched to the antenna and most of the power
is remaining in the IRF510. In such a case, you must check your antenna and
the SWR.
I can't think of any other scenario.
- farhan
On Tue, May 28, 2013 at 10:07 AM, ronbaechle <ronbaechle@...> wrote:
**
My IRF510 get very hot on Bitx20a to the point that I burned one up in a
long transmission.Im not sure if this is normal to get that hot.So the idea
was to get a brushless fan thinking it would be quieter than a brush model.
Please any comments Ashhar. Ps I do have a Bitx20 ver 3 sitting here ready
to build and compare. Ron
--- In BITX20@..., Ashhar Farhan <farhanbox@...> wrote:
Why are you using a fan? It could make the vfo drift more than it should.
- farhan
On 5/28/13, Tom Sevart <n2uhc@...> wrote:
If a larger cap doesn't work, try putting an inductor in series with
the fan
along with the cap in parallel. This should eliminate any whine from
the
fan.
Tom Sevart N2UHC
St. Paul, KS
--
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