Re: Echoplex heating up?

[kflint@annihilist.com (Kim Flint)]

>Rob wrote:
>>I noticed on Harmony Central effects reviews that a user had a thermal
>>problem with the Echoplex containing a full 16MB of memory, so that
>>some of the controls would not respond.  Has anyone had this problem,
>>and also heard of possible solutions?
>>
>>Rob

Dave replied:

>No one has mentioned the thermal problem, and I'd nearly forgotten about 
>it.
>I took the precaution of putting the Obie at the bottom of the rack, with 
>an
>empty space above it, and then all other devices above it. I don't know if
>it's necessary and I wish I could rack it wherever I want...but so far, so
>good.
>
>
>Kim - what's the sordid tale on this little problem?  Hopefully limited to
>some of the first few that shipped???
>
>dave at studio seventeen

I already answered this, but I guess it bears repeating. There was a small
design error that caused strange behaviors when the Echoplex was hot. The
usual symptom was that pressing the Undo button would execute Record
instead. Basically, a pin on one of the IC's was connected to +5 volts when
it shouldn't have been connected to anything. This didn't have any effect
normally, but when the unit got hot you would see the problem. Cutting the
pin fixes the problem, and the Echoplex works fine at much higher
temperatures.

Newer units should have this fixed. I don't know which serial numbers would
have the mod, but probably any unit newer than 9 months. You can do the mod
yourself pretty easily if you feel comfortable working on electronics. You
just need to cut pin 5 of U12, the IC with part number ADC0804. If you are
facing the front of the unit, pin 5 would be the 5th pin from the left end
of the chip, on the front panel side.

If you don't think you can do it yourself, any competent electronics tech
should be able to handle it.


kim

______________________________________________________________________
Kim Flint                   | Looper's Delight
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