E30 alpine CM5908 Radio

[odysseyuk]

Hi Everyone! 

I recently bought a 1990 E30 convertible which has the CM5908 radio.

it was working fine when i first got it but now it turns on but i get no sound.

i did buy a used amp and replaced the old one but still no sound. I'm really not 

sure what's wrong or what to check next any help would be greatly appreciated. 

[Jdesign]

4 hours ago, odysseyuk said:

Hi Everyone! 

I recently bought a 1990 E30 convertible which has the CM5908 radio.

it was working fine when i first got it but now it turns on but i get no sound.

i did buy a used amp and replaced the old one but still no sound. I'm really not 

sure what's wrong or what to check next any help would be greatly appreciated. 

I think we need more information.

Have you checked fuses?

Have you checked grounds? 

Have you checked if its getting 12v at the back of the head unit?

Did it make scratching or odd noise before it failed?

Was it just dead on power up one day? 

Is there static coming from the speakers now? 

Do you know if the Amp was tested? Are the capacitors on the amp board good? 

Are the Output Capacitors good? < based on a quick internet search, I would guess this is your issue.

 

[P_Roloff]

52 minutes ago, Jdesign said:

I think we need more information.

Have you checked fuses?

Have you checked grounds? 

Have you checked if its getting 12v at the back of the head unit?

Did it make scratching or odd noise before it failed?

Was it just dead on power up one day? 

Is there static coming from the speakers now? 

Do you know if the Amp was tested? Are the capacitors on the amp board good? 

Are the Output Capacitors good? < based on a quick internet search, I would guess this is your issue.

 

Also, seems stupid, but did you check all the inputs to make sure it isn’t just one of them that failed; I.e. a bad auxiliary input cable 

[odysseyuk]

On 9/7/2023 at 2:45 PM, Jdesign said:

I think we need more information.

Have you checked fuses?

Have you checked grounds? 

Have you checked if its getting 12v at the back of the head unit?

Did it make scratching or odd noise before it failed?

Was it just dead on power up one day? 

Is there static coming from the speakers now? 

Do you know if the Amp was tested? Are the capacitors on the amp board good? 

Are the Output Capacitors good? < based on a quick internet search, I would guess this is your issue.

 

Thanks for the quick response. The radio comes on but no sound from the speakers front or back. 

I thought it was the amp because i replaced it and the deck started working but then i put the old amp in 

and that worked too. It would come on randomly but recently it doesn't work at all. There is power at the 

amp (white wire) and i pulled the tape deck and there is power there too. fuse at the deck and amp are good.

Not sure where to go now. This car did have a power antenna but it had been removed i'm not sure if this has anything 

to do with the radio not working. where would i check the grounds ? 

[odysseyuk]

On 9/7/2023 at 3:38 PM, P_Roloff said:

Also, seems stupid, but did you check all the inputs to make sure it isn’t just one of them that failed; I.e. a bad auxiliary input cable 

This vehicle does have a CD changer in the back. I did unplug everything at the back of the deck and plug back in. 

This is my first BMW and I don't know much about wiring. Any advice would be a great help. 

[Boris3]

This might be useful:

Understanding E30 speaker and amp wiring - R3VLimited Forums

[odysseyuk]

On 9/9/2023 at 2:46 PM, Boris3 said:

This might be useful:

Understanding E30 speaker and amp wiring - R3VLimited Forums

This is really useful! Thank You!