Looking for Presonus Firebox Schematic or High Res photos

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mikefatom

Well-known member
Joined
Apr 5, 2009
Messages
640
Location
Toronto, Canada
Hello everyone,

Does anyone have a schematic for the presonus Firebox? I have one with a burnt resistor and a blown cap.
I just want to get those replaced but I can't read the value off of the burnt resistor.

Thank in advance!

Cheers

Mike
 
Hi Mike,

Interesting coincidence here. I have just requested the Firebox schematic from a person at Presonus who has sent me some parts in the past. I'll let you know how it goes.

Here is a shot of the power supply section which is what failed on this one:

http://imagebin.ca/view/oLXgW6.html

The capacitor at the top of the picture (red circle) failed explosively. The cap at the lower left did not burst, but failed. The resistor near the top (red box) burnt up, and the switching regulator (lower right box) burnt up as well.

I'd be curious to know if any of these components are the same as failed on your firebox.

Kind Regards,
Chris
 
Well, replacing the bad components fixed the 48V supply leg and the firebox is working great again.
 
The resistor in the red square was burnt and the capacitor right below it (in the picture) blew up.
I actually got a hold of a used Firebox and checked out the components marks. I replaced the resistor and the cap but the cap blew up again after very short use. I didn't go any further with it... it's not worth it.

Glad you got yours working. I don't know if we had the exact same issue though...

Cheers

Mike
 
Hey guys, new member here.  My Firebox crapped out and apparently has the same issue.  The 33uf cap popped and the resistor next to it burnt.  I can't see the colors on the resistor but in the posted photo (thanks fbc) it looks like brown black brown with silver= 100 ohms.  Is this correct?  The other circled items in the photo appear ok but I will replace the 470uf cap in the lower left corner since it may be gone as well.  Any luck with the schematic?  AND- why the h.e. double hockey sticks is this issue repeating itself like this?  Obviously a design flaw that Presonus should correct (maybe has in latest versions).....
 
one of my friend have the same issue with his Firebox, I have replaced the 33uF cap but I have over 74V on that cap (rated for 63V) can someone tell me about the value of the resistor (on the red box) and what code have the regulator? it just say 815 if I`m right.

best regards,


Rafael
 
replying me to me the code of that resistor is 4990 or 499ohms.

the regulator is not a regulator it is a power shottky diode.

anyway  I changed the resistor and it burnt again. the LM2586S-ADJ seems to be working well, I have 3V +12 and -12.

I think the burning part is from the phantom power but I still don`t know how it work, it should use the same flyback but why it is burning parts???  if the flyback have a short I shouldn`t have the other voltages ok.
 
Hi guys

I got a Presonus Firebox, and guess what? Yep there is a blown 33uF cap inside. I would greatly appreciate any information that may help me fix this, as I do not appear to have any other burnt parts. Chris; (fbc) I would love to see the photo that you posted to the link above, but for some reason, I can't load the picture. If you could email it to me it would be great.

Regards
Greg
 
Further to my previous posting, I have just managed to fix my Presonus Firebox. In the end, as well as the 33uF, I also found a 24V 500mW zener open circuited and a 470uF 16V elect which was completely dry, and appeared to be the cause of the failure of the other two components.

For details and other observations, see here:

http://cdn.head-fi.org/b/ba/ba79f989_howIfixedmypresonusfirebox.jpeg

Regards, and thanks for your postings, which prompted me into trying to fix it in the first place.
Greg
 

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