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

[Keith Saunders]

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.

 

[Glitch]

Keith Saunders wrote:

With a signal (music would be best) plugged into the phono socket

One could also use MP3 sine wave test tones which might make it easier to do comparisons.

Glitch

[Keith Saunders]

Glitch wrote:

One could also use MP3 sine wave test tones which might make it easier to do comparisons. Glitch

Yes I agree..

[KolfMAKER]

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!

[KolfMAKER]

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?

[Author]

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