Re: DX7 Memory Corruption

"geoff baltan [email protected] [YamahaDX]" <[email protected]>
Newsgroups gmane.music.equipment.yamaha-dx
Message-ID <CACCEbVHeMsBSZy=29kxQAGCff0Nxq_g==7LdV6sS+hda_iQ-7Q@mail.gmail.com>
This is very helpful - so thank you, everyone for the input.
A few questions:
1. The device doesn't immediately lose its memory at power-off, it usually
takes about 8 hours. If the diode were simply open or closed, would it
still partially-work?
2. Is there a list of appropriate replacements for the diode and tantalum
capacitor?



On Tue, Sep 4, 2018 at 1:39 AM, [email protected] [YamahaDX] <
[email protected]> wrote:

>
>
> Daniel,
>
> What pnetops said, and yes, open circuit means no connection, like a
> simple switch that's off / open.  Closed circuit means like a closed switch
> (on), allowing current to pass both ways.
>
> The diode is meant to only allow current from the battery to the RAM when
> there is no external power supply providing 5V, and ideally no current at
> all the other way, though there might be a few microamps.
>
> A healthy diode conducts best when the voltage at the anode is about 0.6V
> higher than the voltage at the cathode - for a silicon one, or about 0.3V
> for a germanium diode... it varies, depending on the material and type of
> diode, but it's generally in about that range.
>
> A dead diode either doesn't conduct at all, or conducts like a small value
> resistor, with little or no difference in direction...
>
> Since the batteries were soldered in, a lot of these synths still have the
> original ones because it's not trivial to change one, but a lot of those
> original batteries still work, after all these years.
>
> - Andy
> 
>
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