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
I´ve done a restoration on a 4400.
New caps and trimmers. (kit from Dillen)
Also two new 10000 uf caps
Everything is good. Idle current is set.
I have one question though: How do you clean the switches properly?
I did mine with compressed air - contact cleaner - and then contact cleaner with lubrication
Before the restoration, it had problems with low volume in the right channel. This was fixed by the cleaning of the switches, so thats good. But sometimes, when i turn it on (tape1, tape 2, phono or whatever) I doesn´t turn on. if i repress the button firmly, it turns on...and stays on, but somehow, there is omething rotten in the switching system. Any ideas?
This was also a problem before I cleaned them.
Another thing: When you set the preamp trimmers for volume in the right and left channel, you are supposed to use fm for volume starting point. Because of this, i havent replaced those two trimmers, that set the fm volume. Service manual says og set them to 75 watts? Do you need scope for this, or am i missing something obvious?
Best regards - Kasper
Hi
looks like this one has been hanging around for a while now....I think you have probably done as much as you can regarding cleaning the switch assemblies. Your problem with the main on/off swich is a common fault and as far as I know there is no cure but replacement, this is a very difficult and arduous task, that is if you can find a replacement switch in the first place. I think the most popular solution is to bypass the on/off switch and turn on and off at the mains supply socket.
As for your volume issue I just measure the resistance of each trimmer when I remove them, as one leg is to ground you only need to ensure you measure from the wiper to the other leg for a fairly accurate measurment, set the new trimmers to the same value and replace....this works for me.
Craig
Your problem with the on/off switch is probably this, the contact "strips" are getting burned and comes lose at last.
I solved this in a BL 5000 with a micro switch
Collecting Vintage B&O is not a hobby, its a lifestyle.
Thanks for the replies. I actually have to beomaster 3000-2, that are absolutely only for parts. The switch looks similar. Maybe I´ll give that a try.
If your Beomaster 4400 has a serialnumber lower than 1524001 the mains switch from Beomaster 3000, 3000-2 and 4000 will be identical.Later Beomaster 4400s have a completely different front panel, different mains switch, different switchrows, different potentiometers, and also a different tuner frontend if I remember correctly.
Replacing the power switch is a 10-minute job.
Martin