#1
I just replaced four caps in the power section of a Mackie VLZ SR32.4.
I have it open and I turned it on and I hear a buzzing noise. I investigate further and the transformer is vibrating. I'm assuming this is very bad.
I also notice that the channels are showing signal and the peak indicator light is on. The VU Meter is maxed.

I'm thinking maybe I put the connector from the transformer on backwards?
I checked the numbers that show which way it goes and it is in the right way, perhaps Mackie didn't wire it to coordinate with the connector numbers.

I haven't been able to locate a schematic of the mixer anywhere.

Thanks for any help. I'm ****ed if I don't fix this as this mixer isn't even mine.
..I was watching my death.
#2
I put some headphones into the mixer, and a really loud buzzing noise comes through. There is no way to control it.
..I was watching my death.
#4
Quote by LeviMan_2001
sounds like you put a cap in wrong! that or one is fried.


I put two of the caps back to regular. Those didn't show any signs of leaking so it's not those.
I'll try putting all the regular caps back in.

I did notice a scratch on the bottom side of the PCB that is going right across the channel one fader. I don't think this has any relation with the buzzing though.

What would happen if you wired the transformer backwards? This transformer has eight wires coming out and seven go to the connector. If I were to put the connector backwards, what would happen?

I am ****ed if I can't fix this by the end of the day... Any help would be greatly appreciated. Even if it is a one-liner post.
..I was watching my death.
#5
How strong is the "vibrating" that your feeling? Humming or buzzing from the transformer isn't inherently bad, nor is very light vibrating Answer those for me and I'll think more about the question as well.

I have the most important test of my life (It will decide if I get my degree this semester or not and whether my salary quadruples two weeks from tomorrow or not) Tuesday morning so I'm studying quite a lot so if you wait a day or two I should be able to help you a lot more.
#6
Could be that it just needs bolting down a bit tighter. All is not lost.
Was lacking a decent sig. Still is.
#7
I posted my question on the Mackie forums last night, and someone responded with a very helpful post, except with the transformer thing, the wire colours changed since 2001 and he was answering from the new viewpoint.

Anyways, here's what he said:
Quote by Mike Rivers

If this is an SR32-4 VLZ Pro, here's the pin arrangement for the power transformer connector J2.

1 - Brown
2 - White
3 - Brown
4 - Orange
5 - Orange
6 - Blue
7 - Blue

The two red wires (48v) go to other points on the board, J3 and J6

Your problem doesn't sound like you have the connector turned around (you'd have to work pretty hard to do that anyway), but rather that it's missing either the +16v or -16v supply.

A drawing of the power supply board is here. You might have the 3-pin connectors along the edge of the board swapped. Check the power supply output voltages at J107. Note that the digital (5V) ground and the analog grounds are separate. Read 5V between pins 1-2 and the other voltages referenced to pin 6.


I'm not exactly sure how to read the power supply voltages at J107. It's a 7-pin connector which connects the power supply to the main PCB.
Perhaps you could tell me how?

Thanks for any help. It is greatly appreciated.
--timbit

EDIT:
Quote by XgamerGt04
How strong is the "vibrating" that your feeling? Humming or buzzing from the transformer isn't inherently bad, nor is very light vibrating Answer those for me and I'll think more about the question as well.

I have the most important test of my life (It will decide if I get my degree this semester or not and whether my salary quadruples two weeks from tomorrow or not) Tuesday morning so I'm studying quite a lot so if you wait a day or two I should be able to help you a lot more.


I found that one of the bolts holding the transformer in has become extremely loose. I tightened it up and the vibrating seems to have stopped. Now that I think of it, I do recall the mixer humming even before I opened it up.
I've read about putting a wood shim between the coil and something else(Research at 3:00 in the morning is pointless. ). I'd rather not touch the transformer at all, I've ****ed up this mixer enough already.

That must be a lot of stress on you right now. I know the feeling, I'm feeling it right now. I swear my hair is going to turn grey at the age of sixteen...
The most I could ever possible wait before people start getting pissed off is untill tomorrow night. I could possibly get one more day and say there's been some unexpected issues. Their vocal jazz class can go without mics for a day...
..I was watching my death.
Last edited by timbit2006 at May 1, 2011,
#9
http://www.mackie.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=163457&#Post163457
That's the thread where Mike is helping me out.

When checking the volts between the -5V and the ground I am getting 0V.
When I put my probes on the -16V, +16V or +48V and Ground It is like the 5V is acting as the ground(Example: +48V to 5V, Voltage is 48V).

Mike has provided me with this drawing of the power section: http://imgur.com/AtULG

I need help urgently. This needs to be fixed by tomorrow night. Preferrably by the end of tonight.

EDIT: Link to the power section schematic.
http://i.imgur.com/PWFFg.png
..I was watching my death.
Last edited by timbit2006 at May 2, 2011,