Behringer noise with Phantom power on

[Gord]

Hi guy's,

I am new on this site and was wondering if I could use some of your trouble shooting experience.

I have a Behringer 3282A that powers up fine but when you turn on the phantom power you get a hum and after about 2 seconds you get a popping noise. If you solo every channel you hear it.

I have checked the voltage from the power supply at the board and what I am supposed to have is.

+5
+17
-17
+48
+12

I have at the board:

+5.04
+16.87
-16.51
+76.51
+12.07

I am checking the voltage right at the board.

The power supply that I am using is brand new (waited 3 months for the thing) when I sent the board and the powersupply to the behringer repair centre in Toronto they said there was nothing wrong used a pile of hot glue to glue down the connectors and sent me on my way.

The board still has the same problem so I took it apart and above is what I found. Does this tell me that the power supply is damaged (power regulator - phantom side), as the voltage is doubled or should I measure the Phantom power from a different source on the board?


Thanks in advance.

Gord

[Enzo]

Sure looks to me like your +48 regulator is shot, and sending unregulated +76 into your circuits.

In the power supply, find IC4, an LM317 three-legged voltage regulator IC, and see if it is bad or unsoldered. I'd just replace it, myself.

I am assuming this is an MX3282A?

[Gord]

Thanks Enzo,

Yes it is a MX3282A, in your opinion do you think I just fried the 48 volt circuit beyond the regulator as well and that the poping static like noise are the all of the capacitors that are no longer working?

I will check the regulator in the morning.

Happy New Year to you.

[Enzo]

I have no idea, fix the power supply and find out.

[Gord]

Thought I'd just give an update.

Replaced the LM317 voltage regulator cleaned up the contacts and fired up the power supply and everything seems to work fine. Just doing a burn in to check out the system over time and so far everything works.

Thanks for the help.