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-   -   Mackie SRM450v2 schematic? (http://www.diyaudio.com/forums/class-d/187212-mackie-srm450v2-schematic.html)

lumanauw 17th April 2011 02:34 AM

Mackie SRM450v2 schematic?
 
1 Attachment(s)
I got a burnt Mackie SRM450v2. It burnt in the SMPS section, around UC3842, LM339. Many tracks and PCB and SMD components are inrecognizeable.

The unit use switching power supply, a classD for woofer amp, andLM3886 for tweeter amp. Different from old SRM450

Anyone has schematic or service manual for this active speaker?

authlxl 17th April 2011 08:23 AM

Maybe circuit like JBL EON series ,if possible,paste more pics here

lumanauw 17th April 2011 03:46 PM

6 Attachment(s)
Here's some more pictures

darkfenriz 17th April 2011 07:30 PM

It looks like only the boost pfc preregulator got burnt, the main half bridge looks alive.
why don't you first try to bypass the pfc and run the half bridge only?

authlxl 18th April 2011 02:33 AM

1 Attachment(s)
On our concept in,Mackie almost good quality,we have redraw it SRM350 series amp years ago,bass use class H and tweeter use CLASS AB chip.in new version srm450v2,same not good as our idea.

most of it circuit have shown in it user manual and website introduction,you can find it below:

Mackie - SRM450v2

user manual

http://www.mackie.com/products/srm45...rm450v2_om.pdf

Block digram paste here:

lumanauw 18th April 2011 05:06 AM

Hi, Darkfenriz,

It seems this UC3842 is used for PFC, but also for regulating the output stage. The push-pull transformer is using SG3525, but the pulse is 50%, so the output of PFC is regulating the output voltage of the smps.
The woofer is using IRF classD driver with +/-75V, and LM3886 for tweeter is working at +/-39V.

Now the PFC won't work at all. Always blown the UC3842 and the PFC mosfet. Many SMD components like SOT23 transistor and resistors are burnt.

I think there is very difficult to fix this amp without schematic or service manual

Eva 19th April 2011 03:47 PM

Are you sure that it is UC3842? Was the old IC recognizable? Recent 8-pin continuous mode PFC controller ICs are becoming more and more common (IR1150), even with a second PWM output in them (FAN480x).

If you can't find a schematic, draw your own. First the PFC, then the push pull and input rectifier, leaving "?" boxes for unrecognizable parts. Don't be lazy, the SMPS layout does not look that difficult.

fcruz 19th April 2011 04:38 PM

and what your email so I can send the schema srm450v2

hauer0361 11th June 2011 08:19 AM

email: :cop: email address removed :cop: - I want to get the scheme srm450v2 with pulsed power supply.
Thanks friend!

dadogalardi 21st June 2011 01:30 AM

same problem with srm450v2
 
hello! i have same problem with SRM450V2

it's burned a lot of comps.
it's possible to have the schematics?

my email is :cop: email address removed :cop: , Thanks a lot!


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