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Thread: Help find a manufacturer

  1. #1
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    Default Help find a manufacturer

    I'm hoping that some of the electronics guru's on here can help me.
    I am trying to find data on a 8 pin SOIC, it is manufactured by IT (I cant find any manufacturer that just uses IT as its logo), the part number is LM555S and before everyone says its a a timer its not .
    It is from the driver board inside my DPSSL psu.
    I've found it listed on some of the chinese chip search sites and they also list the manufacturer as IT but they dont have links to a IT website.
    Any help will be much appreciated.

    Jim

  2. #2
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    Default




    That was all I did find on google

  3. #3
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    Default

    That is a 555 timer. A very very common chip

    Most likely used for the TEC PWM in a DPSS at a guess
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  4. #4
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    Or...used for turn-on delay of the diode reference driver
    very common
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  5. #5
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    Default

    Agreed, the 555 timer IC is *quite* common. Here's a website that sells them for 70 cents (And that's Australian cents!) http://www.lazer.com.au/parts.shtml

    Even though you might think a "timer" has no business inside a DPSS power supply, believe me, that's what it is. You'll find these suckers inside *all kinds* of circuits. (Speed controllers, dimmers, tone generators, flashers, modulators, buffers, you name it!)

    Here's a good primer on the 555 IC: http://www.uoguelph.ca/~antoon/gadgets/555/555.html

    Adam

  6. #6
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    You're right it is a timer.
    Obviously I was being blinkered by the manufacturer that I had never come across.
    I've drawn the circuit out, the only output is to the A1 input of a DM74LS08M (quad AND gate).



    Does anybody know who IT are though?

    Jim

  7. #7
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    I've never heard of them. It could be a clone of a Texas instruments chip though. I've seen foreign knock-offs do that from time to time - switch the letters around and try to pass it off as an original.

    No matter though. A 555 IC is a 555 IC, no matter who makes it. If you're certain that the chip is bad, you can pick one up at most any electronics shop and solder it in place. (Over here they even sell them at Radio Shack!) Good luck!

    Adam

  8. #8
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    I'll scope the chip but I expect it to be ok.
    555's tend to be robust little things.
    I expect the 7408 more likely to be faulty as pin 9 and 10 are tied together and have a pull-up resistor which should bring the pins high thus giving a high output which is then routed to pin 2, when pin 2 is high and pin 1 high (being brought high by the timer) you get a high output from the 7408.
    The thing is pins 9+10 are only at just over 1.2v and the only reason I can imagine doing this is the 7408 being faulty.
    I'll pull that and replace it (cost a few pennies over here) and see how I get on.

    Jim

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