Guys, how can I replace the 3300uFx25V capacitors from Nippon Chemi-Con AVF ? These capacitors are installed after the 7812/7912 stabilizers and power the operational amplifiers. The size is limited to a diameter of 16 mm.
No one that has experience and reads datasheets puts 3300 uF after 78xx/79xx regulators. These are used for filtering and minimizing ripple voltage right after the rectifiers and before the regulators. Directly after regulators a small value cap should be used. Directly at the opamps pins normally there are also small value caps to decouple the opamp.
First I don't see 3300 uF after the regs at all (but still too high values 2200 uF and 1000 uf) and secondly this is mediocre designing.The regs are the 500 mA max versions.
Caps could be 22 uF and 10 uF if they are physically close to the regulators.
There are other curious design choices as well like the 2 x 6800 uF filter caps for regs that can handle 500 mA max.
Caps could be 22 uF and 10 uF if they are physically close to the regulators.
There are other curious design choices as well like the 2 x 6800 uF filter caps for regs that can handle 500 mA max.
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There, after 7812/7912, 7807/7907 are still installed. But it doesn't matter now. What is important now is what to replace AVF with?
Already replied. You do now that askers have to give information do you? Askers don't do that as askers want answers and don't like to loose their valuable time. No device name/type, no complete schematics and still expect 100% adequate advice?! What is important is to use good quality small value electrolytic caps like Panasonic FC or the like. Like 22 uF and 10 uf 25V.
The decoupling of the opamps should be done as close as possible to the opamps. It makes NO sense to use 3300 uF after regulators and they sure won't decouple the opamps. Have fun with it!
The decoupling of the opamps should be done as close as possible to the opamps. It makes NO sense to use 3300 uF after regulators and they sure won't decouple the opamps. Have fun with it!
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Please reread your own post #1 🙂 I would replace the caps for good industrial reliable stuff only because of age. I refuse to look up the device as I have other things to do but you can check their age.
C918 22 uF 25V/50V Panasonic FC or the like and C917 10 uf 25V/50V Panasonic FC or the like. I still have a ultra low jitter clock 45.xx MHz for Sony devices and I wonder if that would make a difference in stuff that compress audio like MD decks ?! It did in CD players.
C918 22 uF 25V/50V Panasonic FC or the like and C917 10 uf 25V/50V Panasonic FC or the like. I still have a ultra low jitter clock 45.xx MHz for Sony devices and I wonder if that would make a difference in stuff that compress audio like MD decks ?! It did in CD players.
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You didn't look at the diagram well! The CXA8042 is powered from +/- 7 volts, and the operational amplifiers are powered from +/- 12 volts.
Corrected, I am doing other things as well and you mentioned the 7807/7907 that don't have anything to do with the non existing 3300 uF caps. No difference in advice though.
Datasheets of M5F78M12l are difficult/imposible to find but let's assume these are similar to 78M12. Onsemi uses 1 uF input bypass caps and 1 uf output bypass caps in their datasheet.
Datasheets of M5F78M12l are difficult/imposible to find but let's assume these are similar to 78M12. Onsemi uses 1 uF input bypass caps and 1 uf output bypass caps in their datasheet.
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Keep the original values and replace it with panasonic FC for 2200uf and panasonic FM for the digital line decoupling ones.Sony would have used the lowest possible value if they'd consider it's worth doing it...they were always on the cheap side to cut manufacturing loses.
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FC and FM are ultra low ESR especially in the higher values. Bad advice to use these after 78xx/79xx. Those AVF certainly aren’t low ESR.
Unless those caps are actually bad, I'd leave them alone.
If you're intending to hop-on-the-cap-changing-bus....started by nervous obsessed geeks, just because you read something online, do yourself a favor and get off the bus.
Guys, there is no need for a low ESR, since this is an analog power supply. Is it possible to use Silmic 2 there, but with a slightly low capacity value? Well, let's say 1000uF.
Did you ask yourself why is that they used an unnecesary higher value? Higher value electrolitics have lower esr...thus, if it was in their intention to get a lower esr circuit you could probably go with lower capacitance but lower esr.If the designer intention wasn't to have lower esr caps then sony wanted a high capacitance there.If you know better than the designer good luck!
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It makes no sense as 78Mxx/79Mxx are not too keen on very low ESR caps and the regulating circuit needs simple decoupling. The load is not complex either. Also film caps are used with already low ESR. The larger value in parallel can be done with standard capacitors. Don't think brands like Sony don't make mistakes or that all their choices are sound choices. I have nice examples made by Sony at home.
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Put low-resistance resistances after the stabilizers? Let's say about 0.5 ohms each.