46 lines
2.9 KiB
Markdown
46 lines
2.9 KiB
Markdown
Show-stopping bugs needing bodges:
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- Errant connection between R25 and R1. This needs to be severed. [See this image of the bad trace](bad_trace_v1.jpeg).
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- Wrong side of the glide capacitor (C13) is connected to the integrator Op-Amp (U3-10). Cut the current trace and bodge from the other leg of the capacitor.
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- Gate stops working after a few due to the lack of a pulldown resistor after D35. Connect a 100k resistor between the 'K' side of that diode (also U2-12) to ground to fix
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this and turn it into a solid square wave. Easiest bodge on the back is probably around the far leg of R21 to the K side of D35, but other options exist.
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- Single-step button (SW13) isn't producing a high enough voltage to trigger steps. Replace C10 with 100K resistor, and bridge out R44 with a wire.
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Assembly Notes:
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- Do not connect the Normal pin for Pause (J19/J18); the schematic is incorrect
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- Wiring SW15 (once/stop) and cascade out is easier done via skywiring; only one cross-board wire is needed, vs 3 if the PCB is used.
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- the current 12-position rotary switches are actually 2p6t, which means only six different step counts are available until the replacement arrives
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- LEDs go in long leg down (from the front)
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- Clock POT is too small; need more than 100k to get below 200bpm
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Schematic fixes:
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- C1 is too small for a 1uF capacitor; expand a bit, but also size it for a box film cap instead of the 600v monsters we've been using
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- C3 and C4 could use larger spacing
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- C7 is a ceramic 104 power cap like C5, C6, C8, C9, C11, C12; space accordingly
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- C10, C14 too small for film; is film needed?
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- One socket connection is on the wrong side of the board, adding an extra cross-board wire that shouldn't be so hard.
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- Move any UX connections on the lower board out from under the smaller board, for convenience
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- C10, C14 is a guessed value; could be other values, ceramic may work, test debouncing. Maybe enlarge footprint if needed.
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- Resistor footprint could stand to be +1mm between legs
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-- Don't put R8 so close to R26
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-- D36/R47 too close
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- Trim 5mm from vertical for both panels, to make fitting inside a case easier. Or 10mm if it can fit; losing the bodge area.
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Assembly Tests:
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Ins:
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- Clock In - diode to U2-3
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- Clock In Normal - 1k to U2-8 (AND NOT short to U2-10)
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- Clock Rate - variable resist +6k between U2-8 and U2-9
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- Reset Sw - when pressed, short +12V and Reset In socket
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- Reset Socket to U3-3 = capacitor measurement roughly 15nF (has a resistor as well)
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- Once/Cont When in Cont mode shorts Casc Out normal to Reset In
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- Pause CV In - U1-13 (can get at from top when assembled)
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- Stop Switch - 10 ohms between U1-14 and U2-1 when off, more like 1M ohms when off
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- Single Step - 12V through 10k Ohms to U-1-14, more like 1M when off
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- Glide In - ~27K to U3-8? No, transistors maybe activate?
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Outs:
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- Clock Out - 1K to TP5
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- Gate Out - 1K to U2-14
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- Casc Out - Diode from rotary pin 13
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- CV Out - 1K to U3-7
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