Cap Advice Please

[sparkyuiop]

I have a bad cap in a PSU and want to know if I can swap it with a slightly lower voltage one. I know this is not recommended generally but do you think it would work or be worth the risk trying?
Thanks in advance.

OLD: 420v / 120uf / 105c - REPLACE WITH: 400V / 120uf / 105c

[sparkyuiop]

Re: Cap Advice Please

Well got no answer so I did it anyway and it works fine

[momaka]

Re: Cap Advice Please

Well got no answer so I did it anyway and it works fine

Well, expecting a reply in under 43 minutes is quite unrealistic on a forum. A few hours is somewhat more reasonable.
Anyways...

Before you go with a lower voltage cap, it's always a good idea to check the voltage on he original capacitor first to see if a cap with a lower voltage rating can be used.
Just because the 400v cap is working right now doesn't mean much. If the voltage in the circuit is very close or slightly above what the cap can tolerate, then the cap may eventually die.

[sparkyuiop]

Re: Cap Advice Please

Thanks momaka. I always been an impatient lad!

The originals were 420v and replaced with 400v. Still working but I heed your point.

Phill.

[momaka]

Re: Cap Advice Please

Good to hear it's still working. No need to worry about it anymore, I guess . (otherwise, you would have known by now). Most likely the manufacturer used the 420v cap to get better ESR and ripple current. I would say the voltage on it is probably closer to 385 VDC.