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Hello
I've got a Beomaster 2000 which I found somewhere in our basement. It's not in the best condition, but it worked. However, since a few days the two main fuses keep blowing but I don't know why. I'm using the standard specified fuses: 1A slow, 2 times.
First, I only used the FM mode with an AKG headphone. Worked perfectly, without any problems. After that I got my DIN adapter cable which can be connected to the laptop. Again, I only used the AKG headphone to listen to it. The first time listening to it, I only heard a slight background sound. After pressing the "1 TAPE 2 " button the sound was good. (I guess this button switches between input TAPE 1 and input TAPE 2)
After this, I turned it off. A few minutes later I turned it on again and right at that time I heard a little boom coming from the headphone... Luckily the headphone isn't damaged, fuses were blown though.
I bought new fuses and installed them, but when turning the device on, they immediately blow. Might be interesting to know: when I used the beomaster in FM mode two cooling fins got really hot (almost too hot to touch), even if the volume was on 0 and listening through the headphone. I don't know if this is normal?
This picture might help... This picture is not mine (mine's a little dustier).
http://i40.tinypic.com/2ns2l9i.jpg
What can be the cause for the blowing fuses? I think a short somewhere, but where should I search? I can make some high quality pictures if needed.
I appreciate all help.
Patrick
Welcome to Beoworld !
Sounds like it was initially a case of a too high idle current at the right output stage. This wouldexplain the heat buildup (which BTW should ALWAYS be investigated)A too high idle will eventually cause a damage to something else, the output stage transistors/darlingtonsand power supply rectifier being candidates. This would explain the blowing fuse.
Martin
Thank you for your answer Martin. :)
So, how should I fix this? First check what is damaged: the transistor and/or power supply. But if I repair this, the heat issue will still be there. How can there be a too high current while there's only a headphone plugged in? A headphone doesn't require that much amps...
Byte: Thank you for your answer Martin. :) So, how should I fix this? First check what is damaged: the transistor and/or power supply. But if I repair this, the heat issue will still be there. How can there be a too high current while there's only a headphone plugged in? A headphone doesn't require that much amps...
After finding and repairing the output stages and what else may be wrong, you will have to adjust the idle current and feeds from the transformer if available. A wrong idle current will generate heat as soon as you turn on the power, connected to headphones or speakers or not.
Collecting Vintage B&O is not a hobby, its a lifestyle.
Hi
New to this forum but with a problem similar to the described in this tread, I am happy for some guidence.
My BM 2000 2801 dont blow fuses (yet) but the left side cooling fins do get very hot. Is this atypical idle current issue and how shall I adjust or repair it?
I have the service manual but do not understand if the idle current issue is the same as "TUNING VOLTAGE" or "AF OUTPUT" or any other section of the service manual.
Sorry for amature question buy vill be happy for advice.
Johan
Welcome Johan!
I think the adjustment is called "no load current" in the service manual. You can try just adjusting it, but typically the associated trimpot is shot and will need replacement before the adjustment will hold its setting.
--mika
Wow - what a quick reply !
I checked the manual and I think it must be the "NO-SIGNAL-CURRENT"
Now to the next question: I havent opened the unit yet - can the adjustment be done mechanically (screwdriver) and checked with multimeter or am I supposed to replace some components?
If the trimpot is shot and need to be replaced - how do I know it? and where can I buy a replacement part?
/J