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9790 power header on 9700Midi2cv8 module?
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Author:  James [ Mon Sep 26, 2016 5:19 pm ]
Post subject:  9790 power header on 9700Midi2cv8 module?

Would like to know where the power header would go on the 9700K PCB please.

I want to power the 9700k from a 9771-15. I have a 9790 power adapter kit but I don't see where on the 9700K PCB I would put the header to power the module from the 9771-15?

Author:  PAiA-Scott [ Tue Sep 27, 2016 6:21 pm ]
Post subject:  Re: 9790 power header on 9700Midi2cv8 module?

The same DC power connection area used to tap power from a MIDI2CV8 in a system such as the P9700S can be used to input DC power as a substitute for the usual AC power; however, some changes are required at the power switch and the Power LED section as detailed in the pdf posted here:

viewtopic.php?f=22&t=332

If you'd like to simply things and keep the MIDI2CV8 on its own 12VAC transformer, it may be in the range of 300 to 500 mA vs the 1200mA or more that is optimum for a P9700S. This is assuming you plan to power all the other modules in the system package using the 9771-15. Note too, the R1 and R2 resistors should be sub'ed with wires jumpers on 9710, 9720, and 9730 modules on 15V supplies.

Author:  James [ Tue Sep 27, 2016 8:01 pm ]
Post subject:  Re: 9790 power header on 9700Midi2cv8 module?

ahhh I thought those holes were meant for the header to supply power OUT only. :) Thanks for the clarity.

One more question regarding the modification of the switch / LED for use with a 9771-15 as the power supply.

Per this instruction in the link you supplied:

"..The following changes to the existing panel switch enable a
manual reset. Otherwise, the external supply may be referenced for power-on indication and the power-on reset function and the panel switch/LED circuits may be omitted..."

I can simply OMIT hooking up the power switch and LED entirely on the 9700k, if I choose to let the power LED on the 9771-15 be my indication of power ON and each time I turn on the power at the 9771-15 the 9700k will reset. The 9771-15 has a fast enough power rise that it will send the proper "reset" pulse?

thanks much for the help Scott

Author:  PAiA-Scott [ Wed Sep 28, 2016 12:07 pm ]
Post subject:  Re: 9790 power header on 9700Midi2cv8 module?

I would have to test to be sure, but the voltage rise on the power-up of the 9771 should be fast enough to ensure a reset pulse from the +5V supply to the uC on the MIDI2CV8. If you are already set-up to check it out, powering-up with Self-test mode selected and sending a MIDI message to the MIDI2CV8 input should elicit a steady flashing MIDI Input indicator LED (indicating Status byte/Data byte, etc) and working to tell you the uC has reset and is executing the programming in the EPROM firmware.

Before MIDI2CV8 included v3.0 firmware, it was an advantage having the power/reset switch on the panel, as it was necessary to to operate the switch after making DIP Switch Operating-mode/MIDI-channel settings (only acknowledged on power-up reset); however, with the v3.0 firmware the selection may be via MIDI Control Change messages.

Author:  James [ Wed Sep 28, 2016 5:08 pm ]
Post subject:  Re: 9790 power header on 9700Midi2cv8 module?

I'll test it out as soon as I'm done assembling module this week. Will let you know what I discover.

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