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Cgs synth

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Re: SSG troubleshoot and weird lm3900 behavior

2013-04-13 by cg_synth

Okay, those voltages were more or less what I got.
Now take a 1k resistor and connect one end to -15. Connect the other end of
the 1k resistor to each input pin in turn, and read the voltages. If all is
well, they will read around -14.5 to -15 volts. If any read much higher than
that, that is probably where the problem is.


Below are what I got on those pins with chips IN.

>1) -14.3
>2) -14.3
>3) -14.3
>4) -14.5
>5) -14.8 (Smooth) +14.8 (Stepped) (this will depend on what the module is
doing!)
>6) -14.5
>7) -15
>8) -14.9
>9) +14.2
>10) 0, -0.2 (Stepped)
>11) -14.5
>12) -14.5
>13) -14.5
>14) +15

Other than that, it would be high-resolution pic time.

Ken
_______________________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

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