Re: Polyester Capacitor missing?
Posted: Jan 23rd, '17, 18:26
some components in the BOM get changed because things go out of stock.. so the BOM typically gets updated, someone finds substitute parts..
for the capacitors, what matters primarily is the capacitance value (the Farads)
as for the voltage rating:
if the capacitor is rated for 6V, and you put it on some place in the circuit where it filters the 5V digital supply voltage - it should be okay..
it will NOT be okay if you put it in another place where it's used to filter the +15 or -15V
if you put a capacitor rated for 50V to filter the 5V supply voltage - it will be fine, except that usualy capacitors with higher voltage rating are also bigger in size, and you might find it hard to physically fit it
now, to know what kind of voltage levels are in the circuit - you could look at the schematic
but in general, the audio circuit runs on +15V and -15V and there are usually filtering capacitors between -15V and ground, and between ground and +15V, those are mostly the many capacitors you soldered first on the mainboard around the edges
then there are capacitors in the audio signal which will not be higher than 30V peak-to-peak (because the actual supply rails are 30V peak to peak)
and there's also 5V digital supply which powers the cpu and the other digital stuff (eeprom, shift registers, LEDs, etc..)
so on the mainboard you can safely say that a capacitor rating of 30V is gonna be safe.. you can use higher too, but then such capacitors will typically be also bigger in dimensions
the power rail filtering caps can be be lower too.. maybe even 16V (since they filter +15 and -15), and the digital supply rail filtering caps could be even 6V
on the IO board it's a bit different since there's the power supply section there where AC voltage is rectified and converted to DC, so there can be slightly higher voltages like 42V peak-to-peak or so.. the caps there are big
for the capacitors, what matters primarily is the capacitance value (the Farads)
as for the voltage rating:
if the capacitor is rated for 6V, and you put it on some place in the circuit where it filters the 5V digital supply voltage - it should be okay..
it will NOT be okay if you put it in another place where it's used to filter the +15 or -15V
if you put a capacitor rated for 50V to filter the 5V supply voltage - it will be fine, except that usualy capacitors with higher voltage rating are also bigger in size, and you might find it hard to physically fit it
now, to know what kind of voltage levels are in the circuit - you could look at the schematic
but in general, the audio circuit runs on +15V and -15V and there are usually filtering capacitors between -15V and ground, and between ground and +15V, those are mostly the many capacitors you soldered first on the mainboard around the edges
then there are capacitors in the audio signal which will not be higher than 30V peak-to-peak (because the actual supply rails are 30V peak to peak)
and there's also 5V digital supply which powers the cpu and the other digital stuff (eeprom, shift registers, LEDs, etc..)
so on the mainboard you can safely say that a capacitor rating of 30V is gonna be safe.. you can use higher too, but then such capacitors will typically be also bigger in dimensions
the power rail filtering caps can be be lower too.. maybe even 16V (since they filter +15 and -15), and the digital supply rail filtering caps could be even 6V
on the IO board it's a bit different since there's the power supply section there where AC voltage is rectified and converted to DC, so there can be slightly higher voltages like 42V peak-to-peak or so.. the caps there are big