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
The radio wont find any FM channels as I turn the FM dial or the preset dials.
Mv and LW works fine.
It does feel like the FM radio is not accepting any tuning, as I doubt I can hear ny changes from turning the main radio dial ( yes the thred is okey ) or the preset dials. Like it is on one and the same frequence, nomatter what capacitor dialed.I have opened the machine into service mode and followed the internal antenna cable to the board under the record player and tried connecting an FM antenna diectly on the radio board under the recordplayer , but no difference
Any tips of error tracking ?
Christian ChristensenSweden
My re-capped M75 are my precious diamonds.
considering if i have a faulty FM PCB?Do anybody know if the other models at the same period used the same PCB?...thinking if i in the future find a usful part/model.
I can probably find something in the dungeons.
http://archivedarchivedforum2.beoworld.org/forums/t/24219.aspx
Martin
That would be lovevly, Martin !
Hi I had an identical issue with my BC7700 that had not been used for a while and it turned out to be the PSU. Check the supply voltage to the FM board. I seem to recall that its supply is uniquely via a 40uF Bipolar capacitor on the PSU/main amp board and in my case this was cracked an defective. A new Bipolar cap restored normal operation. Richard
Thanks richtoy
that tip together with the soon arriving tunerboard, from Martin, will definitely increase my chances to life in the radio.
Step by step , the goal is the important matter.
Christian
Richtoy
I am studiying the diagram,,looking for 40uF bipolar caps on the PSU modul, modul 3. and I can only find C15 and C212 which is 47uF biploar.
Are you sure it was 40uF?. I have seen some unusual values in Beovox crossovers, but 40 uF is not, to my knowledge particular common value.
Hi,
Sorry typo, it was C15 and it was 47uF.
It feeds 30v to the FM section (a44) via d68. If the cap fails the FM section gets no 30v.
Richard
Okey, BC7700 back in Service mode
So of course i started with greatfully checking Richards tip about the 30 voltage supply to the tunerboardMessured fine 30 volt on the P8-15, Which takesme back to my suspicion about faulty tunerboard, unpacking the box from Martin and finds this nice little tag :)
Replace the tuner board, and WOOOOW the tuner has normal operation again!!!!Easy repair, and I am incredible happy.Thanks Richard for sharing your experience.Thanks incredible much Martin, for your kindness of selling the board and taking your time to send it. I Appreciate this very higly.
Well done !And thanks for the feedback, glad I could help.