Mackie SRM450v2 schematic?

lumanauw · 17th April 2011, 02:34 AM

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

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

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 · 09:28 AM

email:

email address removed

- I want to get the scheme srm450v2 with pulsed power supply.
Thanks friend!

dadogalardi · 09:27 AM

hello! i have same problem with SRM450V2

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

my email is

email address removed

, Thanks a lot!

19th April 2011, 03:47 PM	#7
Eva diyAudio Member Join Date: Oct 2003 Location: Near the sea	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. __________________ I use to feel like the small child in The Emperor's New Clothes tale

11th June 2011, 08:19 AM	#9
hauer0361 diyAudio Member Join Date: Jun 2011	email: email address removed - I want to get the scheme srm450v2 with pulsed power supply. Thanks friend! Last edited by wintermute; 15th July 2011 at 09:28 AM. Reason: email address removed

21st June 2011, 01:30 AM	#10
dadogalardi diyAudio Member Join Date: Feb 2011	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 email address removed , Thanks a lot! Last edited by wintermute; 15th July 2011 at 09:27 AM. Reason: email address removed

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17th April 2011, 08:23 AM	#2
authlxl SINEWAVE ELECTRONICS CO.,LTD diyAudio Member Join Date: Jun 2006 Location: CHINA	Maybe circuit like JBL EON series ,if possible,paste more pics here

17th April 2011, 07:30 PM	#4
darkfenriz diyAudio Member Join Date: Jun 2004 Location: Warsaw	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?

18th April 2011, 05:06 AM	#6
lumanauw diyAudio Moderator Emeritus Join Date: Oct 2002 Location: Bandung	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

19th April 2011, 04:38 PM	#8
fcruz diyAudio Member Join Date: Apr 2011	and what your email so I can send the schema srm450v2

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