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Old 02-23-2018, 02:45 AM   #1
Ike Mhlanga
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Join Date: Feb 2018
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Default FBT Mitus Active Stage Monitor 210 MA

Hi,

I am trying to resuscitate a dead Mitus 210MA.
Everything seems ok on inspection. No Physical damage except FB5 on the input board which I suspect to be a Fast Blow Fuse of the surface mount type. Apart from that The unit is dead.
There is power up to the rectifier of the SMPS and I get about 300V Dc.
I need a schematic for the unit. FBT Mitus are Italian.
Ive tried to communicate with them but it seems English is the barrier here.

Any help will be apreciated.

Regards

Ike
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Old 02-23-2018, 07:19 AM   #2
Khron
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Default Re: FBT Mitus Active Stage Monitor 210 MA

"FB" would indicate, to me, rather a ferrite bead.

Can you trace, at least vaguely, where that trace goes, and/or where that comes from?

Photos of the board(s) would help, too.

<edit>

Just for kicks, i looked up FBT over on http://www.elektrotanya.com . Got lots of results (arranged alphabetically), scrolled down to F, found a bunch of FBT things. The only FBT Mitus was "Promaxx".

Downloaded the PDF, and whaddya know - it's all the same (with one or two component options) for loads of models - Mitus 206LA, 112A, 115A, 212 FSA, 118 SA, 121 SA, 210MA and a few Promaxx models as well.

https://elektrotanya.com/fbt_mitus_p.../download.html

Suspicion confirmed, FB5 is indeed a ferrite bead, from the pin 1 of the two input XLRs to circuit ground (via the ground lift switch).

Power supply's on page 6. I'd start with checking if there's any voltage across DZ1 (schematic says it should be 18v).
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Last edited by Khron; 02-23-2018 at 07:31 AM..
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Old 02-26-2018, 02:07 PM   #3
Ike Mhlanga
Ike
 
Join Date: Feb 2018
City & State: Harare
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Line Voltage: 240V ac
I'm a: Professional Tech
Posts: 3
Default Re: FBT Mitus Active Stage Monitor 210 MA

Hi Khron,

Thanx a lot for the feedback. Its very much appreciated.

I will download the schematics and give feedback.


Regards

Ike

Last edited by Ike Mhlanga; 02-26-2018 at 02:14 PM..
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