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BitX40 R3 schematic

N7PXY
 

Gentlemen,

I have looked at a number of schematics but do not seem to find the one matching the current Bitx40 R3 transciever being sent from India.

Could someone please point me in the right direction or send a link to the correct file(s)

Tnx,

PJH, N7PXY
 


All the best P JH
sarma
?vu3zmv

On Tue, Feb 21, 2017 at 7:21 AM, N7PXY <hickspj467@...> wrote:

Gentlemen,

I have looked at a number of schematics but do not seem to find the one matching the current Bitx40 R3 transciever being sent from India.

Could someone please point me in the right direction or send a link to the correct file(s)

Tnx,

PJH, N7PXY




--
Regards
Sarma
?
 

This is likely about as good as it gets: ??

A few minor changes:

? The two diodes D15 D16 are now a single BAT54S, so the balancing pot at R105 is not not needed or stuffed.

? ?No C103, no L4, all BC849's are actually MMBT3904's.

That should be pretty close. ?Are you seeing anything else?


On Mon, Feb 20, 2017 at 11:21 pm, N7PXY wrote:

I have looked at a number of schematics but do not seem to find the one matching the current Bitx40 R3 transciever being sent from India.

?
 

R104 ?

At 21/02/2017, you wrote:

This is likely about as good as it gets:??

A few minor changes:

? The two diodes D15 D16 are now a single BAT54S, so the balancing pot at R105 is not not needed or stuffed.

?? No C103, no L4, all BC849's are actually MMBT3904's.

That should be pretty close.? Are you seeing anything else?
 

Yes, I do recall someone reporting R104 being 10k instead of 2.2k. ?

Raj, any news about that emitter resistor at Q13? ?Is it being left at 100 ohms? ?Fine with me, as the few reports we've gotten of Q13 blowing have likely been due to a nearby transmitter. ?But once mine arrives, I'll likely be replacing that SOT23 2N3904 at Q13 with the larger TO92 for better heat dissipation. ?And add your dual diode hack.

On Tue, Feb 21, 2017 at 07:00 am, Raj vu2zap wrote:

R104 ??
 

Jerry, That was me on R104.

No idea on 100 ohms emitter of Q13.

I propose to parallel on Q13.

I tried to blow the transistor Q13 with my main rig on 40M but BITX on a wire.. did not blow.
The double diode should be a good protection.

Raj

At 21/02/2017, you wrote:

Yes, I do recall someone reporting R104 being 10k instead of 2.2k.?

Raj, any news about that emitter resistor at Q13?? Is it being left at 100 ohms?? Fine with me, as the few reports we've gotten of Q13 blowing have likely been due to a nearby transmitter.? But once mine arrives, I'll likely be replacing that SOT23 2N3904 at Q13 with the larger TO92 for better heat dissipation.? And add your dual diode hack.

On Tue, Feb 21, 2017 at 07:00 am, Raj vu2zap wrote:
R104 ?

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