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E & L Instruments Inc. Adam 5005 Main Frame

Discussion in 'Electronic Repair' started by nick, Apr 9, 2013.

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  1. nick

    nick Guest

    I have one of these very old trainer breadboards that has several replaceable modules. The problem I have is the function generator module "101A Function Generator" does not work. No output signal except for the dc offset. I have checked the power supply rails and they seem to be good. I was lookingfor any documentation or service information.
     
  2. I bet it uses the Intersil 8038, the vintage is right and that device did
    come out a tad earlier than the similar in function but not identical Exar
    function generator ICs. Open it up and check, if it uses that IC then it
    will be easy to find a sample circuit that it likely is following. If the
    IC is bad, there were later variants of the IC that are either directly
    plug in or similar enough to plug in with some changes.

    It wouldn't be in the Bug Books, those were just about the TTL.


    Michael
     
  3. nick

    nick Guest

    Makes sense I've seen a similar modern design but the problem is that one DIP has a heat sunk glued to it and I can't read the part number. It looks like this is the part though. Chip has positive and negative power but no output signals. I suspect its the chip. If the passive components had driftedthere would be some type of signal and all I get it the same noise patterns from all three output pins.
     
  4. Find a datasheet for the 8038, and count pins. It the "unknown" IC has
    the same number of pins, then press on. See what pins the voltage goes
    to, if that's a match, press on further. With the schematic of a sample
    circuit in front of you, it's actually easier to then see if the circuit
    matches the sample than to trace out the wiring and then compare.

    Michael
     
  5. nick

    nick Guest

    Thanks for the tips. I took the chip out and put it in a breadboard with one of the example circuits. Since there was no signal output with the chip in either circuit I suspect the chip. At this point I'm not going to bother finding a replacement IC.
     
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