The Workbench

Re: Beomaster 6000 Type 2253

Dillen — Tue, 12 Jul 2011 00:17:46 GMT

I agree.
Check also that the large rectifier, you took out, has been fitted back to
the Beomaster with correct polarity etc.

Martin

Re: Beomaster 6000 Type 2253

Step1 — Mon, 11 Jul 2011 18:09:25 GMT

Nice to see someone working on this amp!

Regarding the capacitor can't tell as long as you have the polarity correct and that the one required bridge is connected then you will be fine.

Obviously it sounds as if the amp needs attention, but before this I would disconect the power plug that goes into the amp board and see if the processor fires up without it. If not work on this first, then look at the bias & offset pots which are probably ready for the bin!

Re: Beomaster 6000 Type 2253

BoxOPwn — Mon, 11 Jul 2011 16:59:08 GMT

Finally back to working on this.

I did make the necessary connections with the new capacitors

Checked for cracked solder joints, but haven't found any. Checked the trimmer in the reset circuit, its still in one piece.

Here is a video of unit attempting to turn on, not sure if this helps at all:

http://s665.photobucket.com/albums/vv19/BoxOPwn/Beomaster%206000/?action=view&current=Boot.mp4

I have noticed a burning smell that occurs when the unit is initially plugged in and attempting to boot. It seems to be coming from resistors 243 and 244 on board 9, which I assume must be overheating if they are becoming hot enough to produce smoke.

Re: Beomaster 6000 Type 2253

Dillen — Thu, 23 Dec 2010 16:25:38 GMT

Well done so far !

When you replaced C1, did you mount a capacitor of similar type or did you introduce
the connection that went away with the old capacitor (the grounding has three points around
the positive pin and two of them are used).

Check for cracked solder joints at the bottom edge of the processor board (when open in
service mode), that's the row of connectors.
Also the module sitting at the bottom of the Beomaster, just below the processor.
That's module 6 if I remember correctly. Cracked solder joints are often seen where
the connectors are soldered to the board.
Finally, the processor reset circuit can fail. There's a trimmer in that circuit that sometimes
fails because of oxidation or simply comes apart physically.

Any and all of the above can be triggered by the unavoidable vibrations from servicing.

Martin

Re: Beomaster 6000 Type 2253

BoxOPwn — Thu, 23 Dec 2010 14:48:12 GMT

Capacitor C1 was shorted, and I replaced it and C10. It turns out my tests on the original rectifier were incorrect, as I compared the original to a replacement. I decided to put the original rectifier back in the unit. The beomaster is no longer blowing any fuses, but it is still not operating correctly. When it is plugged in, the relay will click on and the volume indicator will briefly light up, but then the relay will click off. The standby light is not on, and the unit is unresponsive. I am not really sure where to go from here.

Re: Beomaster 6000 Type 2253

BoxOPwn — Wed, 15 Dec 2010 17:10:03 GMT

I have been unable to work on it , as I am currently at university. My winter break begins next week and I will begin repairs then.

Re: Beomaster 6000 Type 2253

chartz — Wed, 15 Dec 2010 10:36:10 GMT

Hi,

Any news?

Re: Beomaster 6000 Type 2253

Dillen — Wed, 01 Dec 2010 01:57:00 GMT

Yes, C1 and C10.
C1 in 80% of the cases but I suggest you replace them both.

As Jacques as says, it's very rare to see one of those large rectifiers fail and
I don't remember replacing one in a BM6000 either, but of course that doesn't mean
that it won't ever happen.

Martin

Re: Beomaster 6000 Type 2253

BoxOPwn — Tue, 30 Nov 2010 23:09:27 GMT

The Jack is not shorted, but I plan to remove it.

I did in fact remove the rectifier for testing, but perhaps my testing methods were incorrect.

Re: Beomaster 6000 Type 2253

BoxOPwn — Tue, 30 Nov 2010 23:06:08 GMT

Thanks for clearing things up Dillen, looking at the schematic now this makes much more sense.

I beleive the capacitors you are refering to are C1 (3300uF 16V) and C10 (2200 uF 40V).

Re: Beomaster 6000 Type 2253

chartz — Tue, 30 Nov 2010 02:38:00 GMT

Hello,

Have you checked on the female jack, there could well be a short inside!

How did you test the bridge rectifier? I have never seen one of this kind blow in 30 years!

Nice pictures by the way!

Re: Beomaster 6000 Type 2253

Dillen — Tue, 30 Nov 2010 02:20:26 GMT

The large rectifier is not related to the blown fuse. That'll be the rectifier on the regulator board.
On the same regulator board are two large aluminum electrolytic caps.
In your Beomaster one of them has a piece of tape on it.
It's very common to see one of them (or both) shorted.
That is by far the most common reason for that fuse to blow.

The two large (yellow sleeved) electrolytics are usually fine and the large rectifier should not be measured in circuit.

The external connector, I don't know. Maybe power supply for a Discman, a preamp or similar.

Martin

Re: Beomaster 6000 Type 2253

BoxOPwn — Mon, 29 Nov 2010 20:47:55 GMT

I should also mention that a previous owner soldered wire to both ends of D3 on PCB 6. The wire exits through the bottom of the Beomaster, and is terminated with a 3.5mm jack.

I beleive that PCB 6 is for motor control. What possible purpose could this serve?

Beomaster 6000 Type 2253

BoxOPwn — Mon, 29 Nov 2010 20:39:38 GMT

I recently acquired a Beomaster 6000 (Type 2253) in non-working condition. Physically it is in great shape, but it will not power on.

Inspection revealed that Fuse 2 was blown.

I thought that the bridge rectifier (16D7) might be part of the problem and after testing, it was found to be faulty.

I am considering replacing it with this part: Vishay 625-GBPC2504-E4

Can anyone confirm whether this would be a suitable replacement?

I would assume that the large power supply caps C20,C21 should also be replaced.

Once I can get it to turn on, I will likely do a full recap.

Are there any other components which I should look into replacing to get this beomaster to power up?