Bose Head Unit Display not Illuminating

[movado75]

The stereo works fine. Everything else functions. Sound is good. The display is just completely blank. Anyone seen this kind of issue?

 

[Old Guy]

Did it happen all at once or was this a gradual loss? The best case is that there is a bad connection on the ribbon cables that connect the faceplate to the chassis and the display is losing power or its enable signal. However, if the head unit has not been taken apart for maintenance that type of failure is unlikely, particularly if all the pushbuttons work and light up correctly. Electrolytic capacitor failure is a common problem; but, I don't recall any capacitors on the faceplate circuit board.

Displays tend to be pretty durable if they are not abused; but, failure is possible. The display appears to be proprietary, so replacement in kind does not appear to be an option. If the power supply on the board has a capacitor problem that could affect the display; but, I would expect that there would be other signs of problems if that was the case.

 

[I_M_Legend]

yeah, sounds like one of the ribbon cables may have come loose.

some links here:

https://www.oeplusdesign.com/faceplate

 

[movado75]

This happened all at once. I had a cassette aux jack adapter in the unit. When I turned off the car, the cassette ejected and the display briefly lit up in a weird star pattern. The display never lit up again after that. All push buttons work and light-up correctly. I'm wondering if the cassette adapter did something internally (like loosen the ribbon cable).

 

[I_M_Legend]

This happened all at once. I had a cassette aux jack adapter in the unit. When I turned off the car, the cassette ejected and the display briefly lit up in a weird star pattern. The display never lit up again after that. All push buttons work and light-up correctly. I'm wondering if the cassette adapter did something internally (like loosen the ribbon cable).

Definitely check the ribbon cable. It costs you nothing to check.

 

[Old Guy]

The cassette mechanism is not close to the location of the ribbon cables so it would be hard for the adapter to interact with the cables. However, it might be worth a check. I would normally say that you can't hurt anything; but, since the head unit (absent the display) is still functional you can make it worse if you damage the ribbon cable connections while doing your exploration. That could render the head unit completely inoperative so take care when checking the ribbon cables. The connectors are not super tolerant of people who are ham fisted. The fact that all your controls work make me think that a ribbon cable problem is less likely.

A star pattern on the display unit would be odd. The display consists of individual segments (you can see their outlines if you look closely at the display face). It is the individual segments that can be commanded to light up. There are a couple of chips that drive the display segments. I supose that it is possible that if the driver chips failed they might have sent out a brief odd unrecognizable pattern before they 'faded to black'.