Andrewembassy

I am returning to this again in hope we have a newly joined radio guru in the forum able to help. My Concert, when turned on, goes immediately to loud volume. Turning the volume **** both directions only results in alternation between too loud and almost silent. When pressed and depressed again, some middle volume sometimes comes on, then as you start turning the **** - it is only loud or silent again. Note that the same **** perfectly works in bass, tremble, balance and fade modes.
Two local radio "experts" disassembled the unit twice and suggest that it is processor fault. However, I strongly doubt it because when the car gets REALLY HOT standing under direct sun, the volume **** miraciously begins working normally. Then, in 10-20 minutes after I start the car and it gets ventilated, the radio goes into this "all or nothing" mode again. What can this be???

Audi-Sav

There could be a number of things wrong with the internals of the unit...I suggest you take the radio out and take it to the dealership...It should still be under warranty...so it should be covered...It would be more pain than it's worth to try to fix it...also, be careful which "experts" take out and dissassemble your radio because itf it is not an authorized Audi technician, it could void the warranty as well as mess up the whole unit...

xburbx

i am not a radio guru, but i went to an audio dealer and asked how hard it is to wire an audi. he said that you have to bipass the amp because if you dont it shoots the volume too high or too low. that might be the problem?

Audi-Sav

the factory amp for the mid range...Maybe instead of wiring the aftermarket amp in link with the factory amp, make all wiring seperate from the rest of the system... I have a 2002 A6 2.7T where I put a mono-block amp to power the sub, and the factory amp to power the midrange..sounds great...But, also, I had a really good installer...

Andrewembassy

There are no dealers here, and purchasing a new unit and delivering it to me in Armenia will cost me over $1,200.

The volume **** in Concert is not a usual variable resistor but sort of digital coder that sends signals to the processor. I believe something happened between the two (remember, strange enough but the **** works well with the rest of functions except volume). I have heard it is a rather common fault with this unit accompanied by temperature differences resulting in volume function failure. If someone had same problem and got the puzzle resolved, I would apprecate him share how.

Andrewembassy

By now I know the problem is widespread. It lies in a Motorola microcontroller chip inside the radio, MC68HC705B32, one sell of which gets
faulty with time. The way to fix it is to replace the chip. For this, you will need a professional electronics engineer to use a special programming device to, first, read the memory data from the old chip, then use it to
program the new one before installation. Some are able to program it so that the fault never occurs again. The "non-recorded" new chip should cost about $7-$15. No idea how much the electronic guru can charge in US. Here in Armenia, they say they can do it for $30. I am currently trying to find the chip.

Jezza

Hi,

Not too sure if you are still a member. Anyway worth a go... Have you sorted the volume problem mentioned above? I have got the same problem. Took the Head Unit into AUDI and was told it was un-repairable (They probably wanted to sell me a new unit)

Cheers