Behringer xenyx 2442fx

[Techknowman]

I have one of these that looks like the power supply is defective.
I cant find any schematics on the unit. so if anyone can tell me what the voltages should be on the connector from the power supply to the main mixer board, that would be great.
And if you really feel like it a part number on the power supply.
And if you really, really feel like it a copy of the schematic
I know that the op amps should have a +/- 12 to 15V on them and they don't the only voltages I read from the supply is +5V and 48V when the phantom power is turned on, so im guessing no +/- 15VDC
Working on Behringer stuff is so much fun!

[soundguruman]

A blown op amp, or shorted regulator. Call them for the schematic.

[Enzo]

Don't waste your phone call, Behringer does not distribute schematics. As a service center we have to sign non-disclosure agreements to get them ourselves.

If you have lost +/15V, disconnect the mixer from the SMPS, and see if they return. If not, the SMPS has the problem, but if they return, then something is shorting those lines up in the mixer. And frankly, a schematic won't help you find a short on a power rail. All the ICs on the board connect between +15 and -15. T1,T2 are TIP31, TIP32 as regulators of these voltages. Might as well see if they have voltage on them. D6, D8 are the rectifiers for those rails, check them for shorts or opens.

Behr labels connectors X something X1, X2, etc. Look right next to that 6-pin one, X3, are there not tiny little letters next to it identifying each pin function? The power supply is thus:
X2-1 - +12
X2-2 - D gnd

X3-1 - +15VA
X3-2 - -15VA
X3-3 - A gnd
X3-4 - +48V
X3-5 - +5VD
X3-6 - D gnd

[soundguruman]

Note to self: never buy a product you can't get the schematic for, never deal with a company that won't give you schematics, for the product you PAID for. That's hilarious, nearly any company in the pro sound industry will give you schematics for free.
That's why we keep buying the product, they support it. If they don't support it......

[Jazz P Bass]

A blown op amp, or shorted regulator. Call them for the schematic.

Ha! Ha! Ha!

[soundguruman]

They actually used to give me schematics, but apparently the policy has changed.
Guess we won't buy their stuff anymore. I hope they are reading this.

[Techknowman]

Depending on the unit, I usually tell the customer to pitch it in the recycle bin. I personally look at behringer stuff as, way over engineered under constructed, hard to imposible to get parts for junk. The last time I ordered a behringer part it took me 6 months to get it. A 10K linear pot.
Anyway thanks i'll check the voltages. I'm almost 99.9% sure its the SMPS. could have been a simple power supply but Berhringer had to make it a SMPS.

[Enzo]

Oh, it is easy to pick on Behringer, but really...

They made it an SMPS because almost everything these days uses an SMPS. Nothing at all wrong with an SMPS. They run cooler, are more efficient, are less likely to introduce hum, cost less, and frankly are darn reliable. If someone tries to tell me their linear power supplies never fail, I don't believe them.

A lot of companies hand out their schematics, Peavey is famous for it. I am a Peavey service center, and recently they wouldn't even send me a copy of their IPR amp drawings - still proprietary. Behringer is the extreme, but not alone. Try getting some Nady schematics, or Line 6.

Behringer stuff is not sturdy like say Rane, but the products generally work well and are a tremendous amount of performance for the dollar.

[Techknowman]

Oh, it is easy to pick on Behringer, but really...

I know!
I just almost never have a good experiance when I have one of there units to work on. I "dislike" Behringer to the same degree I "love" Peavey equipment. Except for that DECA i recently had. Brrrrr that sends chills down my spine.

[Techknowman]

Yea its blown. Looking closer I see that C6,9,12 and 16 are swollen up and had popped.
T2 has a split in it.
Not many parts so im going to replace them all.
Looks like I need 2 TIP32C and 2 TIP31 which I have
I cant read the part numbers on T4,5,6 which are SMD

[Enzo]

Remember all diodes will be fast recovery types.

T4 - BC846B NPN SOT
T5 - BC856B PNP SOT
T6 - BC846B NPN SOT

[Techknowman]

Thanks.
Yea I figured they would be fast because of the switching frequency which i'm guessing is 100 to 300khz.
T4,5,6 test ok but i'm going to replace them just the same.
Looking at the circute i noticed they didn't put any zeners to clamp if the voltage swings to high.
We always put 15V zeners on our 12VDC lines ect to limit overvoltage in the event of a regulation failure which usually blows the protection fuse.
I'm a little concerned about collateral damage knowing the voltages went greater than 25V on the 15V lines popping the 25V caps

[Enzo]

COuld have been overvoltage, or could have been AC on them.

Try feeding the mixer section with a bench supply to see if it survived.

[mozwell]

here you go

[Techknowman]

Thanks. That will be very very handy!