wrote:
I'm restoring a mistreated DX7 to working condition.

Re this schematic:
http://www.bobdbob.com/~deneb/ftp/dxmemory.png

The battery is a lithium coin cell, like a CR2032. D4 on my board has
been replaced with a gigantic power rectifier. I'd like to re-replace
it with a part more appropriate for the application (or at least that
fits through the holes on the circuit board).
[...]
So what I'm wondering is, what kind of diode can I replace this with?
Do I want to go with a Ge diode to keep the available voltage at a
maximum, or doesn't it matter?

Some random, small Schottky (for the low Vf) diode would probably do the
trick. I've seen germanium diodes used in similar circuits, but I
wouldn't recommend one with a lithium cell, as it will leak a small
current into the cell, which they don't like.

Is current an issue?

No. The standby current on those low power SRAM chips is measured in
microamps.

I wish I had
another DX7 to examine but I don't. I can't find a datasheet for the
M5M5118P so I don't know what kind of Vdd it wants.

5V when active. In standby mode they'll retain data down to a couple of
volts.

HTH!


--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
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