Home › Forums › General Discussion & Questions › BeoLab 8000: high frequency noise disturbs switching to OFF
- This topic has 4 replies, 1 voice, and was last updated 7 months, 2 weeks ago by KolfMAKER.
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11 September 2023 at 12:39 #2894
I have an issue with one BeoLab 8000, serial# 1086xxxx
My use: I play music via the RCA input plug in the foot. (So no PowerLink use)
My issue: The BeoLab does not switch back to stand-by/Off. Instead, it switches repeatedly to Off > On > Off, …
What I noticed (both when listening close to the speaker drivers, at 1 meter distance these two matters can not be heard).
- When I play no music and keep my ear close to the speaker drivers, I can hear high frequency noise (especially at the tweeter of course).
- When I touch the casing or the AMP/PSU metal panel, there is a slight hum increase.
What I have done
- Since this is a speaker with old foam, I had to clean the foam rot. So I have meticulously cleaned all PCB’s (incl PCB05 and 06), components and connectors.
- I have checked for broken solder joints or PCB traces (incl. measuring continuity). Couldn’t find them but re-flowed solder joints on PCB 01/02 just to be sure.
- Measured voltage output of Trafo T2: 2x 20 volts DC.
Questions
- What could be wrong?
- What should I do next?
11 September 2023 at 19:13 #22178Update
- On > Off> On > … – When first powering up the BeoLab 8000, the auto stand-by switch works normal and switches from On to Off/stand-by after music stopped. But after some 15 minutes or so, the auto stand-by does not work normal anymore, and switches back and forth between On and Off. (Something to do with warming up?)
- High frequency noise – I found after thoroughly cleaning the track side of PCB01/02, that the high frequency seemed to have gone. But I know noticed that sometimes it is there and then it is gone for a while and returns again.
- Hum – The hum increase when touching the casing or AMP/PSU panel is still there
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