Anyone having issues with S494P PWM switching chips in power supplies?

[o. l. t. 10+ year member]

I have a Planet Audio 4 channel that was playing fine and simply cut off. It does not power up at all so I popped the top an traced the fault to the S494P PWM chip where the ign +12 voltage stops at pin #12 vcc input.

Imagine that, a pulse width modulation chip that is used in switching power supplies as the main building block, and me with an amp that won't turn on..... I bet that's never happened before. //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

So anywho, I've been out of the game for a good while, but looks like I remember everything. The repair won't be an issue, just drop a new IC in it.

Now my question.......

#1- anyone else have issues with this IC?

#2- anyone have a recommended distributor that'll ship me just one hassle free?

Thanks! //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

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[amprepairman 10+ year member]

swap it out with the Texas instruments version...the TI494...

I know the KIA494 is a junker for sure...but the pinout from your diagram looks the same as the TI version...you can get them at MCM electronics and DIGI KEY electronics but Im not sure your gonna be able to get around the minimum order thing...I think most everyones got a 25.00 minimum...I would check your outputs on the chip with a scope before replacing it though...just to be sure its dead...P.W.M. power supplies can do some strange things around the PWM I.C. and it not actually be the I.C....

 

[thch 10+ year member]

you could always see if TI has samples of the part as well. not sure, but generally the worst case is you pay shipping. I've had good luck with TI for samples -- $0 and 2day shipping.