Today was Tuner Day of the current Beomaster 8000 restoration project. The tuner worked basically fine, but there was an intermittency on the right channel, seemingly depending on the moon phase...;-). Tracing the signal with the oscilloscope, revealed immediately that one of the contacts in plug P6 was poor. I pulled the boards apart (they come out together...), and cleaned the contacts with a fiberglass pen and bent them a bit for added contact pressure. Then I added a coat of DeoxIT D100. As usual, this seemed to do the trick. Wiggling the boards did not cause problems in the right channel anymore! Here is a pic of the contacts before cleaning...some black oxide spots are clearly visible where the female headers made contact:
Such black spots come easily off when using a fiberglass pen on them. I forgot to take a picture, but one can achieve as-new looks that way. The DeoxIT further cleans the contacts and provides a protective layer against future oxidation.
While the boards were out, I also recapped them with quality 105C caps. An uneventful procedure. Here is a picture of the boards before the procedure:
And after:
And a detail shot of the region around the IF stage (CA3189E):
Well, almost done!! On to the preamp board (PCB #3)...
Beolover provides professional Bang&Olufsen maintenance and restoration services. We give one year warranty on parts and labor. All parts featured on the blog are available at the Beolover Store. Please, send an email to beolover@gmail.com for inquiries. Enjoy the blog!
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