Using up old chips

Discussion in 'Homebrew and Kit Projects' started by KL7AJ, Feb 12, 2018.

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  1. KL7AJ

    KL7AJ Ham Member QRZ Page

    I "inherited" a pile of analog and digital chips from an estate "sale" (actually a giveaway) about ten years ago....FINALLY finding the time to sort through them all. Lots of PLLs and 555/566s in the lot and some TTL and CMOS. But the real find is a monolithic function generator-on-a-chip. I'm going to use that for a local oscillator for a vlf receiver. Not sure what I'll do with all the PLLs, but I suppose one can never have too many of those.
    Stay tuned.
     
  2. KX4OM

    KX4OM Ham Member QRZ Page

    I was reading through a QEX last night from a few years ago, and the author designed a PLL signal generator that worked with controlling one of the slim AD9850 DDS boards, with a PIC16877 and a 12F675 for the rotary encoder. He used the PLL to replace the 125 MHz crystal on the DDS.

    Ted, KX4OM
     
  3. KP4SX

    KP4SX Subscriber QRZ Page

    Melt them all down and make a big POWER amp chip out of them :)
     
  4. WG8Z

    WG8Z Ham Member QRZ Page

    Crunch them up and put them on top of a casserole.
     
    NE1U likes this.
  5. WN6U

    WN6U Subscriber QRZ Page

    Send then to Pat, W6MHZ.
     
    KD4MOJ and KF5RRF like this.
  6. N2UHC

    N2UHC Ham Member QRZ Page

  7. N1OOQ

    N1OOQ Ham Member QRZ Page

    I made a "handi-finder" using a 555 once.
     
  8. WA9SVD

    WA9SVD Ham Member QRZ Page

    Hi Eric,

    Not all "olde" IC's are obsolete. The venerable LM723 (and other manufacturer's equivalent) regulators, even though well over 35-40 years old, are still in use, even in some "new" designs., and won't go away any time soon. The same goes for IC's such as the ubiquitous '555 timer chip. Even original TTL digital chips have a place, even if lower power (or faster) versions are now available. Sometimes power consumption or speed is not the most important consideration; only the logic matters. Put them to use, rather than resigning them to "e-waste."
     
    KB0MNM likes this.
  9. N1OOQ

    N1OOQ Ham Member QRZ Page

    Yup, I use the occasional TTL at work, when some simple logic is needed. We have some chips from the 80s that work just fine, and the DIPs are hand-solderable!
     
    KB0MNM likes this.
  10. KB0MNM

    KB0MNM Ham Member QRZ Page

    There are still a few 'surplus' electronic stores that might offer a few bucks for your TTL and Linear chips, especially in the sometimes discontinued DIP packages or even cans. Just be aware that they are usually worth a bit more if: 1. They are in the original 'blister' packs or rails. 2. The labelling is clear. 3. They are more rare, discontinued parts eg. Exar manufactured some specific parts without second-source.
    Please keep them out of the landfills at any cost. If the chips have more than 20 pins, they may have a bit of gold inside or be of category 3 above. Be aware that some CMOS chips eg. 4066 are known to be high-failure due to static-sensitivity. Please consider using a wrist-strap and conductive mat to equalize charges before handing CMOS or most FETs eg. MOSFETs. Signetics TL08xx and TL07xx chips have op-amps that also should be protected. Other ( still in business ) brands may not be as sensitive, yet still the strap-handling is a good idea.
     

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