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Could be a recitifier but more likely capacitors and I recommend you replace the lot. A kit is available.

Martin

Hi

Is the hum on one or both channels? 

Do you get the hum from all sources, tape, phono & radio?

Does it vary with the volume & tone controls?

The problem is likely to be an leaky eletolytic capacitor and user Dillen will be able to supply you with a kit that will allow you or a technician to replace all of them.

Regards

Richard 

Hi guys, 

I have jumped in on this thread as is relevant to my issue. 

I have a Beomaster 1900-2903 that developed a hum. After consulting this wonderful forum i bought a bulb replacement kit (several of them were blown) and cap kit from Dillen and performed the work without incident. 

The unit played beautifully for around 6 months but has now developed a hum again. The hum is present irrespective of which input is selected and can be modified by balance and tone controls. The hum is on both channels.

I am wondering if anyone can please give an idea of what might be worth looking at. I was so excited to get it up and running again after emplying Dillen's excellent kit and now am totally bummed that it has gone wrong again.

Thanks very much in anticipation!

Cheers,

jonathan

My Beomaster 1900 has started to develop a hum too. (Bit only whe using the tuner)  How many capacitors  need to be replaced, and is it a difficult  job to do?

Simon

Did you replace the rectifier too ? I am referring to the board-mounted one next to the main board fuse
and capacitor C92 (not the large square one with soldered leads, sitting near the round mains transformer).
If not, I suggest doing so. The original (round type) rectifier is really a bit underdimensioned and pulling the load
of the old caps for any period of time haven't done it any good either. Mount something a little more powerful.

Another issue with Beomasters of this series is mains voltage sensitivity.
If your Beomaster is set to f.e. 230V but your mains actually is only 220-225V, it may cause a bit of hum, even
more so with the original rectifier still in place.

The cap kit contains more than 60 components. Replacing the caps is not difficult but takes a bit of time.
Soldering and basic electronic skills and tools are required.

Martin

Hi Martin and thanks for the feedback,

I only replaced the capacitors and lamps as supplied in the kit i bought from you. I will try replacing the rectifier you mention. Can you please give specs for this component? (What do you mean by a 'little more powerful'? - sorry, my knowledge is limited).

Thanks v much,

jonathan

The current rating of the original rectifier is a bit too low, especially
as the old capacitors dried out and the general circuit current increased.
The new rectifier should have a current rating somewhat higher than that
of the original.
I like to mount a square type, something like a KBPC 608 or 610, the
leads can easily be formed to fit into the PCB holes and there is adequate
room for the component.

Martin

Hi again Martin,

To follow up this thread, i have replaced the onboard rectifier with a new KBPC608PBF as per your recommendation. Unfortunately this has not solved the hum in both channels that i am experiencing (panned with balance control and modified by tone controls - present across all inputs).

I attach a picture of the old rectifier unit just prior to removal (to confirm the correct one).

The voltage setting is set to 240v on rear of the Beomaster and i am in central London so presume the supply voltage is pretty accurate to this (?).

I am wondering if you could please suggest any other avenues that i should investigate? I'd hate to have to throw the unit out as it is beautiful condition. Again, thanks for your help and advice, much appreciated.

Jonathan (London)

Yes, that's the one but it has already been replaced by ... something.

Of course there can be other faults.
- Correct control panel lamp wattage ?
- Correct idle current settings ?
- All capacitors replaced ?
But check your mains voltage with a good multimeter (carefully of course).
It may be considerably lower than you expect.
If lower than 230V, you can switch the Beomaster to 220V.
It won't damage it since it has been constructed to accept voltages of up
to 10% over the setting.
Pull out the mains plug BEFORE rotating the voltage setting switch since it will travel over a much
lower setting on it's way to 220V.

Martin