[DaveBern]

My GD-01 head unit suffered the dreaded 'no sound' issue.  Initially I could get sound by pressing the on/off button repeatedly, but eventually even that failed to work.  I got a quote for $330 to fix it, which is crazy, as I could install a better unit for less money.  In another Hyundai forum, someone mentioned that they fixed their (different) unit by discovering that the screws that hold down the main board, and earth it to the chassis, were loose.  With nothing to lose, I removed the unit (very easy to do) and with half a dozen screws, gained access to the main board.  Sure enough, all 4 securing screws were loose.  They even have earth symbols on the board next to them.
I tightened the screws and reinstalled the unit.  It has had about a dozen ignition cycles so far and works every time.  I'll let you know it it stays fixed, but so far so good.  The FM radio is still weak, but I think that's a failed RF amplifier in the roof.
The holding screws tighten down onto earthing pads, and these are covered in solder.  That's a no-no as solder is soft and creeps with time, resulting in the screws coming loose.  I'm surprised that it was built this way, as solder creep is well known in the electronics industry.  Usually the pads are bare copper, and a star washer is fitted to bite and make good contact.

[Shambles]

Great feedback

[mickd]

Good job Dave,
Centre stand and sound system fixes .

[The Gonz]

I was forming a mental picture of star washers before I got to where you mentioned them. Disappointing shortcut in the assembly process. Great job saving a lot of needless expense.

Good fix it job, well done

Wouldn't of helped with my GD-01 unit as it went bang with smoke an all...totally dead

[DaveBern]

Good fix it job, well done

Wouldn't of helped with my GD-01 unit as it went bang with smoke an all...totally dead

The ultimate "no sound" issue.....

[Richo123]

Well done Dave, glad you sorted it . My GD-01 radio wouldn’t receive anything FM or AM when I bought it second hand. After a series of technician bumps and it intermittently working, I pulled out the FM /AM front end module and re-soldered the IC inside. Hasn’t skipped a beat in a few years now. I hope yours is now also as reliable .

[DaveBern]

Unfortunately it has started playing up again.  Still working, but sometimes requiring a power cycle or two.  The fact that disturbing it made it go from not working to working for 2 weeks seems to indicate a dry joint or board crack.  I think I'll look for an Android unit to replace it if I can get one at a decent price, not wanting to spend $600 on a Sony....
I think Richo123 has the solution, but what is "a series of technician bumps" ?
 

[DaveBern]

The head unit finally died completely again.  I pulled it to bits and had a good look over it but could find nothing obvious.  The Black Friday sales were on so i bought a Kenwood DMX1025BT for $252, quite a discount, and cheaper than getting the original unit fixed.  I bought a 2 DIN fascia from AliExpress months ago as I was expecting to replace the unit, so I was ready to go.  Anyway, it's in now and much more functional than the original unit.  Even the steering wheel buttons worked out of the box.  I unsoldered the connector from the old unit so I could make up my own harness with access to the steering wheel buttons and USB port (the commercial adapters don't have these).  Interesting discovery was that the radio in the new unit works perfectly.  It was really weak in the GD-01, and many forum posts suggest that the preamp in the roof dies.  it appears that it's fine, and the GD-01 is just a crap unit....

[macaz]

i,m hearing you dave i tried the shakeproof washers trick on the main board, mine were loose also, i must have read the same post, i also put a seperate earth to the chassis of the unit but made no difference, certainly are crap units, i bought a kenwood M3200BT from SCA for $179 and the facia kit and harness adaptors from automotive superstore for $140 surprised to have everything go right for a change, but problems never end with this car, vent mode now not working.