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Re: echoplex and noise

At 10:50 PM -0800 11/9/98, Aden Evens wrote:
>I just got my new echoplex too. Seems like a great unit. It checked out
>fine on arrival. However, after I installed new RAM, it now generates
>constant internal self-noise. That is, even with feedback turned all the
>way down, the feedback light stays aglow, and recording even a silent 
>yields a loop of fairly loud (though not overwhelmingly loud) white noise.
>It does record from the input if I play something into it, it just sums it
>with the static to create a loop with a s/n ratio of 1:1.

hmm, bizzare problem! so I gather you did try going back to the old simms,
and it did go back to working right again? That would likely mean something
wrong with one of the simms. If it works ok with the original simms than
the echoplex hardware is probably fine; there's not much different between
1MB and 4MB. you might want to try the simms in different pair combinations
to see if you can figure out which one it is, and replace it. weird though,
seems like the simm probably has some bad bits that only interfere in some
places and not all. The feedback LED indicates audio level on the digital
side. If that's the only thing lighting, it's probably some sort of data
corruption happening. Since it's not crashing otherwise, a bad chip on one
of the simms could be it. Or maybe they draw an unusually large amount of
power or are very noisy? I guess a quick thing to do is get some different
4MB simms in there to see if they do the same or the problem goes away.

or it could be the problem with a long screw hitting the transformer, that
Dennis mentioned. seems unlikely that that would just cause the noise and
not some more serious problem, but I've seen stranger things. If that seems
like it, maybe find the short screw or just leave the screw on that side


Kim Flint                   | Looper's Delight
kflint@annihilist.com       | http://www.annihilist.com/loop/loop.html
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