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Subject: Re: Dead 800

From: "selloutdesigns" <aah_public@...>
Date: 2009-03-04

Anyone know offhand if a tl082 can safely replace a tl072? They do appear compatible.

Thanks,

<<aaRoN>>

--- In korgpolyex@yahoogroups.com, Gordon JC Pearce MM3YEQ <gordon@...> wrote:
>
> On Wed, 2009-03-04 at 13:34 +0000, narfman96 wrote:
> > Definitely timing issues with IC36b the interrupt oscillator. Try
> > disconnecting the output at R107 and see if it runs at the correct
> > frequency. If it does the CPU is loading it down somehow. If not then
> > suspect the timing caps C76 or C79. The resistors R102-R104 need to be
> > verified and then the Tl072 op amp itself. This circuit needs to run
> > in the mhz or no go for the LED display and envelope generators.
>
> Bah. Just change the TL072 on spec. Horrible things.
>
> Gordon
>