Motu 896 Mk3. Help!!

G

gaztech

New member
Hi guys,

I have a Motu 896 Mk3. Was working fine up to a few months ago so I put it aside. I decided to get it out to find out why it's dead and found a load of bad blown-out capacitors in the unit. I have replaced these now. Unit now "appears" to come on (all the output relays click on turn-on) but every indicator is blank including the display.

Due to the capacitor issue, I'm sure that this is power supply related - but in order to find out if all is ok I really need to get hold of a service manual.

I've seen many posts talking about Motu and I'm sure I won't get this infomation from them so I'm appealing here. Does anyone have a service manual or a set of schematics for this device so that I can fix it?

Anyone? Any help would be appreciated. Thanks.
 
Hi Gaz,
How confident are you in your work? I'd double check all soldering and cap values+polarities just to be certain.
Tbh, I'd probably replace all electro caps regardless of appearances - I had to recap a motu interface myself a while back.
I'm guessing they aren't using great caps in there.

Is the front panel board hooked up by a ribbon cable? Pop it open and double check all connections.

Probably patronising you here, but we can all miss the 'obvious'.
 
Hi. Thanks for the reply. You are correct of course. The obvious comes along and bites us all from time to time!

I've been repairing gear for over 30 years and yep, I did check everything. All looks ok apart from one thing... this is why I need the schematic.

I checked each cap as I soldered it in to make sure that is was connecting both sides both on top and underneath the board. I've been caught with plated through holes before! All seemed to be ok except for one 1000uF capacitor. Across the cap it measured almost a short circuit. I checked my joints for a short and all was ok. I took the cap out as I thought it might be faulty but the short was still there. Tracing it back, I came across a 0 ohm link which went to a PS79650 voltage regulator (Ref: REG1, Pins 1 and 2). These are the *input* pins to the device so it's very unlikely that there would be a short there! There's obviously something wrong at this point so I really need a schematic to find out what is going on here.

I guess I probably "can" sort it without the drawing but I really don't like lifting components off SMD boards just to check them. It's so easy to damage the board and easy to damage components too when getting them off.

If anyone reading this thread can help me with even the partial part of this schematic it would help. - Or any further advice before I start the process of lifting these components! Maybe someone has come across this fault before? Here's hoping!
 
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