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schematic ambiguities

 

Is C143 tied to U3, or to R144 and T6?

I assume only the latter, though both could use a nearby bypass cap.

Also, RV1 pin 2 probably has no connection into U3.

An ascii netlist would be handy.


Jerry, KE7ER
[email protected]
 

Perhaps the "TX" supply is common to regulator and T6 gets it thro R144.
?the capacitor is connected to decouple R144.
?It appears a short acrossR144.
thus we need to imagine the supply"Tx" going to regulator directly and through R144 and c142 (not c143) to the T6.

?
 

Emacs!

At 29/12/2016, you wrote:


Is C143 tied to U3, or to R144 and T6?

I assume only the latter, though both could use a nearby bypass cap.

Also, RV1 pin 2 probably has no connection into U3.

An ascii netlist would be handy.


Jerry, KE7ER
[email protected]
 

we might need an additional cap at regulator IN to gnd. you may call it C143A
 

LM78L05 datasheet recommends 0.33uF within 3 inches of the input pin. ?The Bitx40 likely has that already. ?It is ?not being loaded very heavily. ? I doubt there's an issue, but would add a cap if the board were rolled.
[email protected]
 

You are talking of the Tx bias regulator.? It won't draw much current except what the presets themselves draw. As such, I don't see any need for additional caps.

Best of 2017
sarma
?vu3zmv

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