Capacitors in PSU?

Question

Electronics

I will not be like the authors of such posts (something recently on Habré it has become fashionable to write about how to solder a capacitor) and I will not write a topic about how I, having soldered a couple of capacitors and soldered a couple of contacts, revived a computer power supply unit.
In general, there were 2 swollen 10V x 1000uF capacitors in the PSU. I didn’t have the same ones at hand and I soldered 16V x 1000uF and 25V x 1000uF in their place (I soldered what happened). Common sense dictates that nothing bad will happen and everything will work fine, but the information on the Internet on this subject varies. I would like to ask experienced and smart habrausers what such a replacement is fraught with?
And another question. The power supply worked and feels good, but the output voltages are a bit high (12.28 and 5.13), but they are stable - there are no drawdowns or jumps. Load - mat. miniITX board and hard drive. How dangerous is this for components?

Answer 1

Regarding the voltages: according to the specification, the tolerances are +5 and +12 V ± 5%, that is, the maximum is 5.25 and 12.6 V, you are all right.

Answer 2

The voltage written on the capacitor essentially shows its margin of safety. Give a higher one - it will break through. You just increased the "safety margin" of the capacitors, and nothing more. If you google on the topic of power supplies - almost everyone recommends installing capacitors with a voltage margin, the only limitation here is that it is better to make the margin reasonable, because. higher voltage capacitors tend to be larger and more expensive.
As for increasing the capacitance - the advice is true for power supply filters, but not in other cases (say, if you significantly change the capacitance of the capacitor in the speaker crossover, you will change the cutoff frequencies and probably ruin the sound). In traditional transformer power supplies (with pulsed ones), the capacitor dampens ripples, there, with an increase in capacitance, ripple suppression also increases, but at the same time, the primary charging current of the capacitor increases significantly at the start.

Answer 3

capacitors can be installed with higher characteristics (16 V instead of 10, 25,000 microfarads instead of 10,000 microfarads, etc.), but not vice versa. So it's all right.

Answer 4

Now you are exposing them to a certain effect, which is slightly higher than the nominal values.

In theory, everything should work like this, but I would play it safe

Captain, relog.

Answer 5

The Chinese put 16V 1000mF air conditioners in the PSU, because they are cheaper, in fact, if you put 1000mF on 25V, nothing will happen, just the horses will have more margin for peak voltage. For example, standard 16V 1000mF swell or explode sometimes not only from peak voltages, but also from temperature in bp. I also put 25V air conditioners instead of 16V and the bp lives even longer than before the breakdown.

Answer 6

Each microcircuit has a certain “margin of safety”, in other words, the difference in indicators within which all components of the circuit work normally (a simple example is the Ilyich light bulb, designed for 220-240V.). Now you are exposing them to a certain effect, which is slightly higher than the nominal values ​​\u200b\u200b(12.28 instead of 12 and 5.13 instead of 5, although, of course, the power supply does not produce exactly 5 and exactly 12v).
The main characteristic of a capacitor is its capacitance. In your case, it has not changed. In theory, everything should work like that, but I would play it safe and go to the radio parts store ...

Answer 7

On the motherboard, you can put electrolytic capacitors of a smaller capacity. Checked. I set instead of 3300 mkf 1800/A with the voltage more carefully. The fact is that a 25 volt capacitor when discharged gives 25 volts. If you replace the 6.3 V capacitor with cond. 25 V, then the motherboard may fail when the capacitor is discharged when the computer is turned off. Well, if there is protection such as a zener diode, a varicap ... And if not ... Definitely - failure of the motherboard.