Vintage Synth Repair

Thanks John, thats very helpful!
Greg

--- In vintagesynthrepair@yahoogroups.com, John Henson <synthnerd@...> wrote:
>
> Hi Greg,
> You are on the right lines but the wrong IC type.
> The 40Hxxx are the Toshiba version of the 74HCxxx series.
> 40Hxxx's are often used in Japanese synths around the memory decoding, 
> reset and battery
> backup systems, and putting 74LS's in there will at least drain the 
> battery very quickly, or at worst
> mess up the logic systems.
> The 40H000 is replaceable by the 74HC00, and I have done it many times, 
> this chip in the Battery system
> does seem prone to failure.
> Regards,
> John.
> >
> > Hi, just out of curiosity, are the TC40HXXX ICs directly compatible 
> > with the 74LSXXX chips? When i search for the description of any TC 
> > chip and match a 74LS of the same last three numbers they both seem to 
> > do the same thing/same description.
> >
> > Still trying to narrow down my issue with my jp6 and it seems the 
> > Tc40h chips in it aren't available anywhere. Hope if i need to i can 
> > swap to the LS series
> >
> > thanks
> > Greg
> >
> > 
> >
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>