Xenyx 1204usb Interface

G'day i have a Xenyx 1204usb Interface after i switch it on it powers itself down 40 seconds later is it stuffed?

If the mixer (it is NOT a proper interface!) shows absolutely no sign of life, LEDs etc, it could well be the power supply, easily checked with a cheap digital multimeter, something everyone should own!

Behringer kit gets a bad name but IMEXP it performs pretty well but reliability can be an issue.

If recording, building tracks is your desired aim you would do well to ditch any kind of mixer for a decent Audio Interface. Three that won't break the bank: Alesis i02 Express. AudioBox 2 and top of the budget AIs ,, IMHO the Steinberg UR22.

Dave.
 
I think its more than 15000 miles to my nearest wallmart thanks for your feedback i will get it tested see what comes of that
 
I think this may be close. This is a UB1204fx power section minus a transformer for the incoming mains. It's a switch mode supply. There's a connection after diode D6 (+UR) that is fed back to an opto-isolator (4N35) that appears to provide voltage regulation to the C input of the TOP245Y.

TOP245Y seems to have protection for current limiting and voltage which may be the cause for a delayed shutdown if there is a problem.
Link to TPO245Y datasheet..... TOP245Y Datasheet(PDF) - Power Integrations, Inc.
 

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Mark, that map reminds me of SMPS circuits in old TVs and I would bet that string of high value Rs, 1,2,3 have gone higher and cannot maintain the startup bias on the chip. Bit of poor design, the TVs used the resistors but then a feedback R from the supply took over.

I do not like the series caps at the input where the centre tap is going to inject mains crap into your local earth. I am even less enamoured of C3 which breaches the mains side/LT side barrier. I hope it is an X rated type!

And WTF discrete transistors for the output regulation? Surely 708/9 chips would have been cheaper and give vastly better regulation.

Dave.
 
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