ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Bought a "dead" BM1900
Realized that it wasnt dead, somebody else had opened it before and the front panels forks didnt grab the pins. Yep it is tricky to get that panel back correct for the forks to grab propertly
Asseblemed back, ran the beauty and realized that the bass controll didnt work..on niether of the channels., ontop of that I could see the membrans of the speakers move slowly back and forward as the slided the control which made me think that no galvanic connections and a capacitive differnece made by my hand movements...so I de-assembled potetionmeter from PCB:No galvanic connection from the either of the channels middle pin of the pot to the tracks made me de-assemble the entire slide potetniometer.The small forks that connected the tracks were supposed to sit in a plastic lock, which had broke. A tough reply from MArtin , a one-oneliner, "potentionmeter was special made for B&O , cant be bought today, you have to repair it"Agony, these things are so small. first tried glueing it, broke again...and after some emailed with Martin, He tipped me of sanding the surfaces before glueing, another glueing, another 24 hours to dry.Yes it is a pair of tweezers up to the right in this image, this repairments was so small, so tricky, so difficult to see with my eyes. Would maybe had been easier with a microcope.re-assmbled the potetionmeter, this time very very careful and did not push it together all the way, in order not to put tomuch pressure on the forks..AND IT WORKEDThis was the trickiest repairment I have done in my life,So my advice to you with BM2400 and BM1900, be very careful useing the sliders. the forks inside of the potetionmeters are held by maximum 0.5mm plastic locks...plastic that is not so strong almost 40 years later. The repairment is very time consuming.But now it works again, celebrate with...of course a glass of nice wine.I still need to replace 2 lamps, but that will be a piece of cake compared to what this repairment was.This was the short version of the story, Martin helped alotHappy, and again, Thanks Martin, Thanks
My re-capped M75 are my precious diamonds.