C1 is bad, no doubt !

Replace it and note that the old C1 had 3 negative pins. All three solder pads will have to be
connected together and to the negative pin of the new C1.
The positive pin goes to the center solder pad.

Martin

Re testing the capacitor - you may be measuring the resistance (ohms) of another part of the circuit!  Unsolder one leg of the cap, then test it.  If you can get hold of an ESR meter, you can test all the electrolytics in circuit (no power on and caps discharged).  Note also, that a meter which just measures the value (capacitance in microfarads etc) of caps is not always good  - it may measure ok but does not function correctly when powered.  This is where the ESR meter is invaluable! I'm sure you will solve this problem soon. = Brian (Northumberland)

Hi,

just a short update to let you know what happened:

I replaced C1 with a new cap today and now the power supply seems to work again. Which means the BM works fine, sound is great, but: The BM keeps switching itself off after about 30 seconds.

Any ideas what might cause this? I had a similar problem on my second 6000 - that one had a fault in the remote receiver. But this 6000 even switches off with the remote receiver disconnected...

Thanks for all the great help so far.

Good job on the power supply !
Happy to see that my first guess was right. 😎

Replace all electrolytic caps in the output stages, note some of them are bipolar.
Check amplifier idle current and DC offset settings. Replace all four trimmers and readjust to factory specs.
Do one channel at a time, starting with the (most) defective channel to prevent the Beomaster from
shutting down while you adjust.

Martin

I already replaced the caps some time ago (at least all except the bipolar ones - I wasn't able to source these).

But I don't think the problem is in the amplifier - I tested the amplifier in the other 6000 and it was working (well, the left channel is missing, but I was going to look at that as soon as everything else works). At least the other 6000 didn't switch off.

Check also the reset circuit on the processor board.
Another thing is cracked solders, especially at the connectors at the lower edge of the processor board and
the whole module 14 board (at the bottom of the Beomaster just below the processor board), check for cracked
solders at the plugs/connectors, there are always a lot of them and they can cause the strangest faults, like
intermittent shutdowns.

Martin

Dillen wrote:

Check also the reset circuit on the processor board.
Another thing is cracked solders.

Well, I resoldered all connectors; sadly that didn't cure the fault. What should I check on the reset circuit? I did a test reset as described in the service manual - it worked as it should.

Maybe it's really the amplifier? When I disconnect the cable that runs from the power supply to the amplifier the BM doesn't turn off. Does that mean I should search for a fault there? I cannot adjust the amplifier trimmers as the BM now turns off after about 5 seconds - a bit too fast.

Another thing I noticed: The clock and the timers do not work. When I press 'Clock Set' three digits glow very pale and thats it. But when the BM has been disconnected from the mains for about three days the clock suddenly works again - but only until the BM shuts down again.

It's really strange - as I said I tested every single board in a second 6000 about two months ago and they all worked fine- except for the power supply and the missing left channel. The only thing I did afterwards was resoldering the repaired displays - maybe something got too hot?

Sadly I do not have the second 6000 anymore, so I can't check it that way.

Check the other caps on module 16 (power supply), where you already replaced C1.

Martin

Hello again = Good to see you making some progress!  It looks like you still have a problem in the PSU.  I wonder if there is a protection circuit being activated, (perhaps Martin  can tell us - also, I'll look myself when I get a moment). 

Meanwhile, try prodding around the board to see if you can localise the fault - sometimes it starts up again, or when running the prod may provoke the fault.  Also try alternatively heating and freezing in selected areas - this very often works with the type of fault you seem to have.  For heat, I use a high wattage wire-wound R powered from a battery - the R in a tube and blow down the tube directing the hot air almost exactly where you want it.  Then try a squirt of freezer - it often works well ie you can detect the fault coming and going.  Of course change as many electrolytics as possible, as Martin has suggested.  Keep us updated. Best luck = Brian (Northumberland)

More = A shot in the dark to try - Check the 5volt regulator, 6IC3 and the big 10,000 mf capacitor, 6C9 (preferably by substitution) = Brian (N)