2970N3

[Snakeyes]

looking for info on bias procedure for N3 amp with the RT1 also does anyone have a schematic and component location for this radio
Thanks T

 

[BayouRadioAmplifier]

is your radio drawing high current when you key it up in SSB mode,
with no audio input?

is the final amp board EPAC40010A ? ? with the eight FET's
( same as in a DX 98VHP )

 

[BayouRadioAmplifier]

also I found this error on the one I worked on.
and the schematic confirms it, on the main circuit board.

RCI-2970N2 / 2950 IRF520 bias problem repair.

While working on my first 2970N2, from another techs hands, found the main transceiver unit was getting hot. low output. the IRF520 bias settings were way to high, and one was acting squirrelly, eventually damaging IRF520 Q62. With the shorting board and Q62 removed from the board, I...

www.worldwidedx.com

 

[Snakeyes]

is your radio drawing high current when you key it up in SSB mode,
with no audio input?

is the final amp board EPAC40010A ? ? with the eight FET's
( same as in a DX 98VHP )

I bought it with blown board I am replacing it and don’t want to smoke the new one yes 8 rt1

 

[Snakeyes]

is your radio drawing high current when you key it up in SSB mode,
with no audio input?

is the final amp board EPAC40010A ? ? with the eight FET's
( same as in a DX 98VHP )

Thank you I knew another radio has the same amp board …. Does any radio share the same smt radio board ?

 

[BayouRadioAmplifier]

the main radio schematic is "RCI 2950DX MOSFET"
first check for the bias problem on the Q62. add that resistor is needed.

on the 8 MOSFET PA board, turn the bias pots, VR2 and VR3 so the wiper is
at ground, so you have zero bias voltage when first turned on.
then monitor the input current, and slowly adjust these for about 200 mA
more input current on each side of the PA. 400 mA more current total.
So hopefully that will be about 50 mA of bias on each MOSFET.