I have an E443 and the circuit diagram shows the power pack only removing a short circuit around two diodes in series with the with the -ve battery rail. See attached. With the power pack installed the E443 only draws power from the power pack because the diodes have -9V or -7.2V at the battery end and -12V from the plug pack which turns the diodes off. For the diodes to be on the voltage at the battery end has to be higher -ve voltage than the voltage from the plug pack.
If there is a mains power fail while playing, the diodes will turn on and supply power from the battery, however the voltage drop across the two diodes means you are effectively running on 1 less battery so run time is reduced. On mains fail unplug the power pack from the keyboard if you want maximum run time from the batteries.
I do not have an E363 service manual, but I suspect it will be the same.
Hi MikeS,
Yes, the circuit near the DC IN jack on PSR-E models, which can also be operated with batteries, will be almost identical. I don't have the
E363 Service Manual either at the moment. But I looked in the Service Manuals of several similar models, including the one from the
E353:
The diodes D506 and D507 (type 10EDA40-TA1B2) you mentioned are obviously NOT INSTALLED, because they are surrounded in the circuit diagram with a
dotted line, which means "The parts which are surrounded by dotted line are No mount." Neither could I find these two diodes in the "Electrical Parts list" of the Service Manual.
So it is very likely with the E363, as I described above, that when connecting the DC plug, the negative pole of the battery pack is
completely disconnected from the internal circuit. See also the attached picture.
Best regards,
Chris
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