Hi guys - Sorry for the very delayed follow-up. Lots of stuff got in the way
this past month. I think diode D4 is good, but I figured I'd see if you guys
could confirm this.
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I finally opened the DX7 back open, and here were my voltages:
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(1) With the unit powered OFF:
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Battery: 3.31v
E! Grey Matter RAM chip U4 (pins 14 and 28): 3.25v
Diode D4 3.25v
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(2) With the unit powered ON:
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Battery: 3.31v
E! Grey Matter RAM chip U4 (pins 14 and 28): 3.25v
Diode D4 4.93v
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(3) I also did a quick retest the unit powered OFF (about 24 hours later).
The battery was accidentally drained a bit due to my accidentally shorting it
for a few minutes during the CR2032 battery holder installation. Hopefully these
are the correctly recorded values:
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With the unit powered ON:
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Battery: 2.83v (a bit drained as I just mentioned)
E! Grey Matter RAM chip U4 (pins 14 and 28): 3.25v
Diode D4 — INACCESSIBLE under Grey Matter board
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NOTE: D4 was measured with the E! board
removed, as you can't access it otherwise. Test points were from one end of the
diode and the transistor that it leads to (as you can't access the other side of
the diode without removing the motherboard).
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So does this mean that Diode D4 is actually fine after all?
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Again, it loses its memory after 15 minutes or so and still has the same
error message/symptoms. Just trying to figure
out the next steps here.
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Thanks again, everyone!
