HiRes pictures from the XIEGU G90 transceiver

 Here are some pictures of the PCBs in the Xiegu G90 transceiver.

The Main unit.

        Control board.

RF Front End Bandpass Filters 

As far as I can identify, there are 10 bandpass filters switched with PIN diodes. Far away from the schematic!

 

 

 

PA RF Board

Reverse voltage protection detail

NTC (Negative Temperature Coefficient resistor) problem

There is a serious gap between the NTC which compensate the bias for the temperature increase and the PA RF transistor case. This is one potential cause for premature failure in the final stage especially in TX intensive modes like FT8.

The solution is to gently bent the pins of the NTC to make physicall contact between them and apply a small blob of thermal silicone GLUE, not usual paste.

This will prevent a future gap due to vibrations or shocks and will increase the mutual temperature transfer thus an adequate bias voltage. 

Before:

After:

Schematic (work in progress)

-I removed the schematic as I found error in the AIC3204 area and I must redraw it. I will find a way to have it updated.

October news

RadioMagazinYO, the monthly YO hams magazine is available for download HERE. It's necessary to register as user in order to dl the magazine but you can wait to the end of the month do have it without registration!
The cover story, about the YR1X ARHAB will be available as article next month.
Meantime, you can watch YR1X-11 pictures HERE.