There is a problem with the amp module on some of these that use the switching amp section. it seems when Behringer stole the design from Yamaha they neglected to duplicate the board layout. The output transistor will arc over and char a path from one leg to the next. sometimes through the middle of the board. IF...this is the case. then when the transistor arcs over, it kills the power supply. often times it kills the amplifier too! can't remember what model that is however.
Huh, what a problem! But... this kinda rattle I hear could be an arc over transistors? First time I repaired it (I didn't change the TOP221 ic, and some hours of use later switching power transistors blew up, and some other things I changed then) there where no rattle...
It's a big help, btw! Thanks!
It's a big help, btw! Thanks!
Hello..!
I have got a pmh1000 with a blown power supply 2..
At first i could only see (also checked with component tester everything on the board) a tottaly fried DIODE (D24 smd) i replaced it with a 1n4007 and powered it up without anything connected (mixer or amp)..
It started working and i could hear a buzzing sound from the power supply...
I left it on for 3-4 seconds...
Then i connected the mixer and it worked grat for another 3-4 seconds..
Then i also connected the power amp..
Left it on for 3-4 seconds and i could hear a buzzing sound from the speakers too...(as loud as the music)...
The after i checked for pieces that may have warmed up (there were nothing heated) i turned it on and left it playing...
I knew the buzzing was not ok but i left it on..
~30 seconds later, it blew up (no popping sound on speaker)
Just a sparkle from the power board and the fuse blown..
I checked the power board and the 4 resistors after the power bridge along with the 17n80c3 mosfets are blown up (haven't seen anything else blown till now)...
Thanks god the power amp is still not fried (checked it again with component tester and everything seems ok...)
Any help here?
Thanks
I have got a pmh1000 with a blown power supply 2..
At first i could only see (also checked with component tester everything on the board) a tottaly fried DIODE (D24 smd) i replaced it with a 1n4007 and powered it up without anything connected (mixer or amp)..
It started working and i could hear a buzzing sound from the power supply...
I left it on for 3-4 seconds...
Then i connected the mixer and it worked grat for another 3-4 seconds..
Then i also connected the power amp..
Left it on for 3-4 seconds and i could hear a buzzing sound from the speakers too...(as loud as the music)...
The after i checked for pieces that may have warmed up (there were nothing heated) i turned it on and left it playing...
I knew the buzzing was not ok but i left it on..
~30 seconds later, it blew up (no popping sound on speaker)
Just a sparkle from the power board and the fuse blown..
I checked the power board and the 4 resistors after the power bridge along with the 17n80c3 mosfets are blown up (haven't seen anything else blown till now)...
Thanks god the power amp is still not fried (checked it again with component tester and everything seems ok...)
Any help here?
Thanks
Check the output transistors, could be that. I hate these PMH1000... it failed all around the world!
I just got in searching again for this for a friends one so i wanted to update on that situation..( i know i am reviving an old thread but it is to add info that may help others!! )
It wasn't the power amp as i am using the power amp since then with an external psu without problems..I never found what it actually was because after the dead diode (the one i have replaced) it burned along with the diode all the power transistors in the psu too and they are not cheap (would cost almost as much as a used one) so i never actually fixed it..I just made a custom psu to power it without the amp and use it as a simple mixer and PSU board has been used for parts..
It wasn't the power amp as i am using the power amp since then with an external psu without problems..I never found what it actually was because after the dead diode (the one i have replaced) it burned along with the diode all the power transistors in the psu too and they are not cheap (would cost almost as much as a used one) so i never actually fixed it..I just made a custom psu to power it without the amp and use it as a simple mixer and PSU board has been used for parts..
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