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Today I made a bunch of progress on the Sequentix P3 I’m currently building. Before today I’d only checked out the parts to be sure most of them were there, looked over everything, and did some general setup to be sure assembly could progress. Today I started fitting pieces, and I’m definitely more than half done at this point.
Because this P3 uses a slightly older board set (v1.5) I had to use this set of older DIY Sequentix P3 directions, but this didn’t prove to be too difficult. While I was able to complete the mainboard, I had to make some slight modifications. It seems that the v1.5 P3 board set only supports MIDI sync or DIN sync. One must read carefully through the main board and IO board pages to figure out what extra components to add, which to leave out, and what to do differently. In short, I had to leave out some parts from the mainboard and fit two capacitors where diodes once went and add in an extra pullup resistor on the bottom of the board.
The two capacitors on the top of the board are intended to add a bit of capacitance to the input lines of the PIC which handles MIDI sync. It is suggested that 220 pF parts be used, but as I didn’t have any of them I fitted some spare 330 pF parts. I don’t think this will cause any problems, and hopefully it won’t. The extra resistor on the bottom of the board is to help work around slow rise times on the MIDI output caused by additional capacitance brought about by the inclusion of RFI filters on the IO board.
I’m hoping to be able to power it up for the first time either tomorrow or Tuesday. How late I get home from work will determine how much I’m able to get done each night.
Here’s a few more photos of parts from tonight:
· Completed Mainboard w/o ICs: Top / Bottom
· Completed upper and lower pot boards.
· Pots for the P3, plus spares, with lugs removed and thick 1/4″ washers fitted for spacing.
· Completed IO board, set up for MIDI sync.
· Completed function switch board.
· Twelve resistors.
· Incomplete keypad board with 1N4148 diodes fitted.
