almost dead densen beat 100

sunrise · 6th July 2005, 04:57 PM

Hi guys,
I have a friend with a big problem...... My friend has buyed an cd player from marantz. Unfortunately the player was working two months and died. The problem is the after the cd has died the amp (densen beat 100) started to behave strangelly.
He asked me what is wrong with the amp (after he asked me if I could look in the amp so if I could repare it maybe). The cd has burned the De Magic from the amp so the amp started to take some strange things at his input. (fortunatelly the amp itself is o.k. - so far as I can determine). The problem is - does anyone knows how could I cut the De Magis from the amp - this is an smd amplifier and it has probably more than one side pcb - I assume that it is two sided. (I would have to take it out from the box to determine that).
Does anyone have some experience with de magic- or some service manual...... I assume that a repare would be expensive because everything is on one pcb and since the pcb is totally burned (at the de magic area) I assume that it would be only possible to replace the whole pcb - expensive.....
here You have few pictures from the amp

sunrise · 6th July 2005, 06:01 PM

another

sunrise · 6th July 2005, 06:01 PM

something went wrong with the first pic

chicco_36 · 6th July 2005, 11:07 PM

I have some badly scanned schematic on paper from first version of Densen B-100, and from your picture, that part (DeMagic) not exist here. On my sch, one ic exist (tlc555), I assume is part of the dc servo circuit.

sunrise · 7th July 2005, 06:45 AM

I have seen de magic in two beat 100 amplifiers. tlc555 is from the protection part of the amp. If You could send me the sch maybe I could see something that could help me further. Thanks for the reply and best regards
tim

sunrise · 7th July 2005, 03:13 PM

I have a fortune that one guy from Densen has decided to help me to solve the problem. So far I have removed R3,R4,R5 and R17 from the Demagic part of the pcb. That disconected the power for the Demagic. The oscilations has stopped.
The problem now is that I have a tiny crackling random noise in the speakers when the amp is turned on. Other than that the amp is working o.k.
The second reply from the guy from Densen said to remove R120 and R220 from the amplifier part of the pcb. That should remove Demagic circuit completely from the amp circuit. I didn't do that yet - since those parts are in the amp section and I want to be 100% sure. Waiting for the confirmation from the man.

By the way - I want to thank the guys from the Densen for their so far help - they didn't need to help at all but they did and I am grateful. Thanks

chicco_36 · 8th July 2005, 01:14 AM

sunrise
I’m glade that you succeeded to repair it with the help of the right place. Densen is great company IMHO. Like I told you, i have barely readable schematic on paper, and I’m unable to transfer it in electronic form…
My version is first one, your model is Mk.3 i think, and here aren’t any resistors with numbers R120, R220.
Good luck!

sunrise · 8th July 2005, 04:16 AM

o.k. - never mind - thanks anyway

best regards
sunrise

sunrise · 8th July 2005, 05:43 AM

Hi,
Crackling has stopped - the reason - large cap on the first picture - I supose that the cap is on the supply for the demagic. Now everything is o.k. - the amp is working normally.

regards
sunrise

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6th July 2005, 11:07 PM	#4
chicco_36 diyAudio Member Join Date: Sep 2004 Location: Skopje, Macedonia	I have some badly scanned schematic on paper from first version of Densen B-100, and from your picture, that part (DeMagic) not exist here. On my sch, one ic exist (tlc555), I assume is part of the dc servo circuit.

7th July 2005, 06:45 AM	#5
sunrise diyAudio Member Join Date: May 2005 Location: delta quadrant	I have seen de magic in two beat 100 amplifiers. tlc555 is from the protection part of the amp. If You could send me the sch maybe I could see something that could help me further. Thanks for the reply and best regards tim

7th July 2005, 03:13 PM	#6
sunrise diyAudio Member Join Date: May 2005 Location: delta quadrant	I have a fortune that one guy from Densen has decided to help me to solve the problem. So far I have removed R3,R4,R5 and R17 from the Demagic part of the pcb. That disconected the power for the Demagic. The oscilations has stopped. The problem now is that I have a tiny crackling random noise in the speakers when the amp is turned on. Other than that the amp is working o.k. The second reply from the guy from Densen said to remove R120 and R220 from the amplifier part of the pcb. That should remove Demagic circuit completely from the amp circuit. I didn't do that yet - since those parts are in the amp section and I want to be 100% sure. Waiting for the confirmation from the man. By the way - I want to thank the guys from the Densen for their so far help - they didn't need to help at all but they did and I am grateful. Thanks

8th July 2005, 01:14 AM	#7
chicco_36 diyAudio Member Join Date: Sep 2004 Location: Skopje, Macedonia	sunrise I’m glade that you succeeded to repair it with the help of the right place. Densen is great company IMHO. Like I told you, i have barely readable schematic on paper, and I’m unable to transfer it in electronic form… My version is first one, your model is Mk.3 i think, and here aren’t any resistors with numbers R120, R220. Good luck!

8th July 2005, 04:16 AM	#8
sunrise diyAudio Member Join Date: May 2005 Location: delta quadrant	o.k. - never mind - thanks anyway best regards sunrise

8th July 2005, 05:43 AM	#9
sunrise diyAudio Member Join Date: May 2005 Location: delta quadrant	Hi, Crackling has stopped - the reason - large cap on the first picture - I supose that the cap is on the supply for the demagic. Now everything is o.k. - the amp is working normally. regards sunrise

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