Vintage Products

Re: Beocenter 3300 - low frequency noise from the speakers

Dillen — Mon, 13 Dec 2010 04:15:00 GMT

Nice job !

The problem with non-latching pushbuttons is usually because the power switch
doesn't release completely. This, in turn, does not release the locking rod inside the switch assy.
If this is the case, you may have to take apart the power switch (THAT is tedious), clean everything
and put it back together.
A spring with a little higher tension for the power switch can sometimes also solve it.

Martin

Re: Beocenter 3300 - low frequency noise from the speakers

Scapino1 — Sun, 12 Dec 2010 15:11:21 GMT

The real problem was actually a muting switch in the buttons' section - placed near P3 button. When I cleaned them before I adjusted a torsional spring and the muting switch was continuously closed. Now everything works - I checked with the muting switch forced to be open. However I have to adjust again this small torsional spring and this is a tedious job and I simply cannot get it right in the way that it mutes a signal while switching the programs. I couldn't also push any button that it stays in its pushed position, but I think it may be also solved by adjusting the relative position between the plastic sliders and the muting switch.

Re: Beocenter 3300 - low frequency noise from the speakers

Scapino1 — Fri, 10 Dec 2010 14:00:36 GMT

Finally had time to make some progress with a repair. I've exchanged all the electrolyctic capacitors in the power supply module. Unfortunately the problem still exists. I also spotted that PCB under the Zener Diode D6 in power supply looks like burned - the surface is black. Do you have any idea what might that mean?

I will continue with exchanging the capacitors in the amp sections and it will hopefully help.

Re: Beocenter 3300 - low frequency noise from the speakers

Dillen — Sun, 28 Nov 2010 02:48:00 GMT

Good job with those buttons !

I suggest you replace the rest of the capacitors in the kit too.
The ones in the power supply section are particularly prone to failure.
You cannot tell if they are bad by looking at them, some will leak - they are easy to spot
but others will dry out and you can't see that.
It's typical for the Beomaster 2200 and derivate Beocenters 3300 and 4000 to mute
when the power supply is unstabile.

Martin

Re: Beocenter 3300 - low frequency noise from the speakers

Scapino1 — Sat, 27 Nov 2010 12:56:42 GMT

All the comments were helpful. I disassembled all the buttons and cleaned them - that works fine now.

I exchanged also 3 electrolytic capacitors - the ones with the traces of leakage - C3,C4,C7 at section 5 (according Beomaster 2200 manual).

Unfortunately the other problem occurs now. When I turn the beocenter on, the single sound appears and nothing more - no sound at all. Moving up or down the volume slider has no effect. The illumination of the frequencies indicators works and the capacitors in section 5 are warm also. I noticed that one from 1AT fuses is missing also. However it has never been there and the beocenter used to work. Any hints what might be the problem now?

Jacek

Re: Beocenter 3300 - low frequency noise from the speakers

Dillen — Tue, 02 Nov 2010 17:36:20 GMT

The service manual is available for download from our main website for silver and
gold members (well worth the small membership fee).
Actually we don't have the Beocenter 3300 manual so you will choose the manual
for Beomaster 2200 since this is the same machine as your Beocenter 3300, only without
the turntable so will be close enough.

I can supply the cap kit and it contains new components for all board-mounted
electrolytic capacitors (read: those that normally fail).

Remove the black metal bar at the rear (losen a couple of screws at the rear edge
near the top).
Remove the large aluminum cover (a couple of screws and one or two plastic holders).
Remove the hinged aluminum lid together with the black metal mounting bracket
that goes across the cooling fins etc. Note that there is a spring for the hinged lid
that needs to be taken care of as you lift off the assembly.

This model is a modular build so not too difficult to work on if you are just a bit tech skilled.
The service manual will tell you all.

Martin

Re: Beocenter 3300 - low frequency noise from the speakers

Scapino1 — Tue, 02 Nov 2010 16:36:14 GMT

Thank you guys for all these comments. Just two more questions.

Is there any manual how to disassembly the beocenter? The amount of screws and complexity of construction resembles a kind of puzzle where unscrewing not a right bolt will result in selfdestruction:).

Where I can get this cap kit? What does it consist of? Does it cover all mentioned problems with caps? Can I get somewhere any diagram to get to know which cap is for what?

Re: Beocenter 3300 - low frequency noise from the speakers

Søren Hammer — Mon, 01 Nov 2010 18:42:52 GMT

As Martin says, the pushing contact mechanism may need cleaning, and

A capacitor problem may cause the unwanted hum. Great machine when working, though :)

-Søren

Re: Beocenter 3300 - low frequency noise from the speakers

Dillen — Mon, 01 Nov 2010 18:12:12 GMT

Beocenter 3300 is one of the classic Jensen designs, great sounding amplifier and
a pretty good tuner too. Worth restoring and using.

The pushbutton problem will be dust in the power switch.
Dismounting and taking the switch apart is a fiddly job but it can be done
and the contacts inside can be cleaned while in there.
Watch out for stray springs and contact leaves when you open the switch.
I did this to a Beomaster 2200 just yesterday (same machine only without the record player).
The other problem is most likely the power supply module in need
of new capacitors, that's very common. It could also be an amplifier issue, too high idle currents
and/or bad capacitors. A capacitor kit exists that covers the whole Beocenter.

Martin

Beocenter 3300 - low frequency noise from the speakers

Scapino1 — Mon, 01 Nov 2010 15:48:14 GMT

Hi All,

Recently when I've finally bought the working well pick-up the new problem arose. Since some time the buttons couldn't be pushed - literally they may have been pushed but they didn't stay in the position, so the beocenter couldn't be turned on. Actually after continuously pushing the buttons (let say after 30 pushes) it may have been turned on. I guess it is not normal. And recently with the same procedures - the low frequency noise appears from the speakers after turning on the beocenter. And more recently it can't be even turned on.

Thanks in advance for help.