BeoLab 8000: On Line/RCA input, always red LED ?

25 replies
Keith Saunders
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Keith Saunders
BronzeFounder
Posted December 4, 2024 at 16:48 GMT
#1667472
Given you only have a basic multi-meter you could try the following, it is a long shot, but worth a try. With a signal (music would be best) plugged into the phono socket use you multi-meter set to AC volts say 1 volt range if it has one, or the lowest available. What we are trying to do here is measure an analogue signal with a AC volt meter and compare the good speaker with the bad. One meter lead on P2 pin 2 and the other lead on each of the following points on both speakers with the same music input.
  • Both sides of C75
  • IC1 pin1
  • Both sides of R136
  • Collector of Tr16
Note any points between the two speaker with a difference.  

Location: Hampshire, England

GL
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Glitch
Bronze
Posted December 4, 2024 at 17:24 GMT
#1667474
Keith Saunders
Offline
Keith Saunders
BronzeFounder
Posted December 5, 2024 at 12:40 GMT
Edited December 5, 2024 at 12:41 GMT
#1667482

Location: Hampshire, England

KolfMAKER
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KolfMAKER
Bronze
Posted December 5, 2024 at 17:28 GMT
#1667486
Thanks again gentleman!

I will start to measure between the ‘bad’ and a good speaker next week. As you suggested Keith, between P2 pin 2 and the listed components.

I have a sin wave app on my phone which I will use as a continuous audio signal.

To be continued!

Location: The Netherlands

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KolfMAKER
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KolfMAKER
Bronze
Posted December 12, 2024 at 12:05 GMT
Edited December 12, 2024 at 12:05 GMT
#1667584
Today I tried starting the comparison measurements. As a reference / working speaker I wanted to use another BeoLab 8000 with serial 16xx xxxx. But I found out that the PCB layout of components is slightly different than the trouble BeoLab I am working on (13xx xxxx), and from the PCB02 drawing I have from the Service manual. To show the difference: first the drawing of PCB02 I have from the Service Manual, and underneath a picture of PCB02 from the 16xx xxxx speaker I wanted to use for comparison. IC1 is still clear, but I am not sure about the position of C75, R136, and TR16. Question
  • Could you help me find where these components are, or maybe you have a visual layout of this PCB02 version?

Location: The Netherlands

My B&O Icons:

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