Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Car Audio and Multimedia

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 05-01-2003, 12:30 AM
haasman's Avatar
Registered User
 
Join Date: Jun 2001
Location: San Francisco, CA
Posts: 3,097
Rear speaker saga: Part II ..... Hot speaker?!?!?

While testing to see what is wrong and why the rear speakers on the wagon, Rear Speakers Do Not Work

I had the left rear speaker hooked up, not touching anything and I grabbed it and to my surprise it was VERY warm. Not burning hot but really warm. There was no sound coming out of the speaker.

The radio was in CODE phase and I was waiting the 10 minutes because the first time I entered the code it didn't take.

Am I missing something here? Why would the speaker be so hot? It does test for continuity.

Haasman
__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)
Reply With Quote
  #2  
Old 05-01-2003, 06:08 AM
Registered User
 
Join Date: Jan 2003
Location: Epsom Downs, England
Posts: 152
haasman,

If the speaker is not working, but is getting hot (if I read your posting correctly) there's probably some DC going to it.

Check with a meter to see if you can read any DC voltage across the speaker (check for AC as well, whilst you're at it)

My guess is that you'll find some voltage across the speaker. If you find say, 6v, the power dissipated in the speaker would be 9 watts, certainly enough to warm it up.

If this is the case, the most likely place for the volts to come from would be a failed output transistor in the power amp of the stereo.
__________________
Paul Gibbons
'93 320CE
'73 Jensen Interceptor (Resting)
Giant Full Sus Mountain Bike
Reply With Quote
  #3  
Old 05-01-2003, 09:21 AM
haasman's Avatar
Registered User
 
Join Date: Jun 2001
Location: San Francisco, CA
Posts: 3,097
Paul

I will check and report back. Thanks for your reply.

Haasman
__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)
Reply With Quote
  #4  
Old 05-01-2003, 01:54 PM
haasman's Avatar
Registered User
 
Join Date: Jun 2001
Location: San Francisco, CA
Posts: 3,097
I measured across the two speaker terminals at the left-rear speaker with it connected and the radio display saying: WAIT

I got about 10.7 volts average measurement.

What does this mean?!?! A failed output transistor in the power amp of the stereo?

Haasman
__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)
Reply With Quote
  #5  
Old 05-02-2003, 04:29 AM
Registered User
 
Join Date: Jan 2003
Location: Epsom Downs, England
Posts: 152
You certainly shouldn't have that level of DC across the speaker......

Yes, it points to a failed (short circuit) power transistor in one half of the pair that drive the speaker output. You'll only know by checking the speaker with another power amp (or the whole stereo if it comes in one box).

10.7V is 28 watts dissipated in the speaker, so it has been working hard doing nothing, but the fact that it's warming up means that it's basically ok.

If the front speakers are working, then 90% of the stereo is ok, so it may be worth having it repaired, so long as the cost doesn't get too close to a new one.

You definately need to check all the speakers in the car by substituting another stereo (borrow one) before you start spending money, electrons are awkward bastards, and will give you false clues if they can.
__________________
Paul Gibbons
'93 320CE
'73 Jensen Interceptor (Resting)
Giant Full Sus Mountain Bike
Reply With Quote
  #6  
Old 05-11-2003, 06:32 PM
haasman's Avatar
Registered User
 
Join Date: Jun 2001
Location: San Francisco, CA
Posts: 3,097
Thanks for all the suggestions and help. Fixed the problem: Rear Speakers repaired

Haasman
__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 02:39 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page