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MB 6582 ,R58 missing connect


xarolium

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If using a 6-pin resistor network in R38,R36,R34,R32,R30, the 6th pin (the pin not inside the white box) serves as 10K pullup which would make R57,R58,R59,R60,R61 redundant.

The exact substitution list is:

6th pin in R38 => R57

6th pin in R36 => R58

6th pin in R34 => R59

6th pin in R32 => R60

6th pin in R30 => R61

You might be getting confused because of the placements.... it's actually the 6th pin in R36 which is connected to U19 pin 10, U20 pin 9 and R58.... and the 6th pins of R39,R37,R35,R33,R31 are not being used.

4234_u20_u19_resistors_jpg3887e05919e6b8

4234_u20_u19_resistors_jpg3887e05919e6b8

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ALSO those capacitors look very big!

If you intend to use the MB-6582 control surface PCB in a PT-10 case, the lower edge of the control surface PCB gets very close to the IC's U20,U19,U18,U17,U16. Those capacitors cannot be much taller than the IC+socket. (I expected people would use small monolithic ceramic capacitors here, as shown in the parts list). Also they make taking out the ICs harder, not that you would need to I suppose.

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and for the caps do you think i need to change it?

Maybe. Check if it is taller than an IC+socket. If it's shorter than IC+socket height, then you don't have to change it. If it's taller than IC+socket height, then it might be too close to the CS PCB. I'm sorry I can't give a better answer - I would have to disassemble my MB-6582 to measure the actual height above PCB - I only know that there is clearance for the IC+socket and maybe an additional 1mm. (FYI I knew it would be close before I built the prototype and fully anticipated using low-profile IC sockets or *shock* *horror* soldering the 74HC165 to the PCB if neccessary).

If you are using this capacitor size here, where else are you using it? What about the capacitors inside IC sockets, and in the audio buffer above the SID ICs? All the capacitors I use are either small ceramic (<100nF), monolithic (>=100nF) or electrolytic (>=1uF)... (ok and some nice 22nF SID filter caps).

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