Xiegu G90 tuning problem M.A.Pinfold ZL1BTB
My little G90 goes well and for what I paid for it several years ago ,though now days I personally think they are now getting a little expensive for what they feature, anyway I digress from the job in hand , I enjoy this little radio and provide I wear my glasses its fine . 70 yr eyes arent as good as they were . I have noticed the odd time when the tuning the operation is erratic the display does follow the tuning knob at times it will tune down but not up ! the quadrature tuning encoder is faulty ! bit poor for a radio that I dont thrash and have only had for 2 years or so ...hopefully the manufacturer will one day come to realise that adding another couple of dollars to the price, they could use quality quad encoders that have a long life and enhance users and non user attitudes to the Brand name..However to get it back on the air , I did have some new similar quad encoders I bought off Ali express in my junk box so I would have to swap them over, Like for Like .. I didnt have anything better and the expensive units are much larger and fitment may be a problem.. not every g90 owner has encoder problem so maybe my encoder was an oddball.
I took the unplugged front panel to pieces but be
carefull as there are two ribbon cables inside that have to be removed . The
socket they plug in to has a east west running black strip that fits over
top of the ribbon cable that disappears under it. to pull out the ribbon cable
this east west strip has to be rotated UP 90 degrees imagine it bites down
on the ribbon cable ( at least in my radio) then the flat cable will slide out
There one for the 9pin "rs232" connection to the body of the radio
I found it easier to unscrew the DB9 off to get at the socket with the
ribbon cable , the other one is a wide ribbon cable that goes to the coloured
front panel display . My display was "siliconed" into the fram work along one
edge so i gingerly sliced the soft silicon with a scalpel that made it
much simpler to remove the ribbon cable and not damage it ( my display
just sat back in position when reassembled ) I was able to remove the pcb that
has 3 encoders, the tuning , volume and submenu features .... note: they
all have the "press in" switch feature
The replacement encoder I trimmed 8mm off the shaft so its the same length
The shaft on the replacement
encoder was too long so I trimmed it using a hacksaw and it in a
vice after comparing old and new . Also my replacement had a indent
cut out of the shaft whereas the original has splines
Be very careful when removing the old encoder, I am a great fan of spring
loaded solder suckers ,The solder used on these boards will probably be
lead free to I routinely apply 60:40 solder to lower the melting temperature of
the new solder , and I then go round and suck out as much solder as I can ,I
find I can get out 90% and gently wriggle the component out be so
careful because the pcb tracks are so fine and also you dont want to damage the
plated through holes .
The Faulty one Quadrature pic ups that touch the rotor
The encoder rotor that turns when you tune the radio
I pulled the old Quadrature encoder to pieces to show whats inside
The new unit was soldered in and the front panel of the Xiegu G90 reassembled
.the units plugged together and turned on , and it
worked ! tunes up and tunes down pushing the tuning knob
jumps by 10 as it supposed to all in all a satisfactory job
and since mine was out of warranty I lifted one end the
band restriction diode ( that conveniently has a white arrow pointing to
it ).. I often wonder about other markets in the world who do
not have strict radio regulations and maybe use these radios
in commercial applications.