Testing a 1488 line driver...
geneb at deltasoft.com
Thu Jan 3 20:05:35 CST 2008
> 1) The 1488 gets the right input signal(s)
> 2) The 1488 gets power
> 3) THe 1488 is working correctly
> 4) The output must bot be shorted to something else
> You have checked (1) -- or have you. The 1488 contains 4 drivrs. One is an
> inverter ,the other 3 are NAND gates. _Often_ the inputs on the latter
> sections ae strapped together turning them into inverters too. But is
> that the caser here? Have you made sure there's not another signal being
> fed into the other input?
I checked the pins on the 1488 according to how they were shown on the
schematic. There are no pins "tied" according to that schematic.
> Now as for (2), check there's +12V and -12V on the right pins of the
> 1488. And that the ground pin is, indeed, groudned. Remember a supply
> might be misisng because osmething is overloading it. Maybe a 1488 or a
> dcoupling capacitor has shorted.
It's showing -0.60v for all the -12v test points.
I'll know for sure whether or not the converter is good once I can pull
and test it.
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