Xiegu G90 Full schematic

 Finally, the schematic of Xiegu G90 is available!

Here they are, in pdf format.

1 PA RF Board

2 Small Signal Board

3 Display Unit

4 Microphone - Remote DTMF Microphone

The board revision is 2.0.6. I have 2.0.7 revision and there are some minor modifications, especially in the power supply line (reverse protection).

Some other resources.

Xiegu G90 Block Diagram and Schematic

Based on work of Bob, W9RAN and some modest contribution from my side, here is the block diagram of the popular Xiegu G90 transceiver.

 

 

THIS PART IS NO LONGER ACTUAL BECAUSE THE FULL SCHEMATICS ARE AVAILABLE

 

And, based on reverse engineering of parts I am interested in, here is the schematic. Attention, it is work in progress!

Last version: September 15, 2021 - minor corrections

I received a very interesting e-mail from Nils, W8IJN. 

Many thanks Nils for the informations:

Adrian,

I've been following your adventures exploring the inner workings of the G90. I've downloaded all the schematic diagrams that you've put together about the radio.

Recently I blew up the two 100 Ohm resistors in the area around the key jack. I sent Radioddity a note and they responded with a schematic of that area. The drawing is included with this email to add to your collection.

The problem came from testing a EFHW antenna with the 49:1 balun sitting a meter from the radio and connected by what turned out to be a faulty cable. The radio wasn't grounded and the key line did not have any RF suppression/chokes on it. I figure the RF got past the RFC and the zener diodes shorted the RF through the 100 Ohm resistors to ground.

I repaired this with parts I had and added 1nf caps on the high/key jack side of the RFCs. We'll see how that works out. Oh, and I grounded the radio and put a clip-on ferrite on the key line.

Stay safe and well, Adrian. We will survive!

73

Nils R. B. Young
W8IJN

There is a small difference between the schematic received from Xiegu and what i found on my board. The supressing capacitors in my radio are between the resistors and inductors while in the picture sent by Xiegu are on the ESD suppressing diodes. This might be from a different revision or even a mistake in my drawing. I will check this soon.

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.

CW and Voice memory keyer for ICOM IC-7300

After a long time I decided to came back to CW.

Just for fun and to use the Pandemia holiday I thought will be interesting to have a little remote for the Voice and CW memory.
While the Voice memory callback is relatively simple with CI-V protocol, for CW memory there are no commands provided by ICOM.
Therefore, the keyer will store the preset messages (10 messages) and send them using a 4 x 4 keypad.
The uC of choice is an Arduino with Atmega 328 on UNO platform.
The keypad is also used to Power On and OFF the radio and TUNE the ATU (I use an AH-4).

The 4 x 4 keypad is able to send: -In CW, 10 preprogrammed CW messages, each of 128 bytes; -in SSB, AM, FM, 8 prerecorded voice messages -"A" is Power ON -"B" is Power OFF -"C" is TUNE

Here is a small video on youtube about this


Here is the code