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?
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?
Attachments
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/srm450v2/pdf/srm450v2_om.pdf
Block digram paste here:
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/srm450v2/pdf/srm450v2_om.pdf
Block digram paste here:
Attachments
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
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
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.
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.
hello! i have same problem with SRM450V2
it's burned a lot of comps.
it's possible to have the schematics?
my email isemail address removed
can I get schematic too ?
email address removed
Last edited by a moderator:
I am hoping to get the schematic as well. I am having the same issue with my SRM450 V2
Thanks for this forum and your help in this matter. -
I have pm you. Thanks for your help.
I have the same amp with similar problems. Just wondering how you made out.
If you got it working and what components you replaced.
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