How often do you guys do a preventative recap?

[c_hegge]

Re: How often do you guys do a preventative recap?

IMO, if it isn't worth recapping with good Japanese caps, then it isn't worth hanging on to.

[Pentium4]

Re: How often do you guys do a preventative recap?

I'm sure the Jamicon would have lasted longer but since they were all on the 12V filtering, I figured those were the best ones to replace if it's going to be seeing a lot of use.

[momaka]

Re: How often do you guys do a preventative recap?

IMO, if it isn't worth recapping with good Japanese caps, then it isn't worth hanging on to.

Well, as far as ATX power supplies - I don't always use them to power computers. In some cases, output ripple isn't important at all and as long as the PSU is working, that's all I care about. Problem is, if the output caps are bad, the PSU may not regulate/function properly. So in those cases, sticking any crappy (but not yet failed) caps in it is already a big improvement.

[c_hegge]

Re: How often do you guys do a preventative recap?

^
Well, bench PSUs are a different story, but I was referring more specifically to stuff which would be used in a PC

[Pentium4]

Re: How often do you guys do a preventative recap?

Since my Japanese caps are too big and it's just an L&C, do you think it's even worth replacing the YC caps with slightly used Teapo and OST caps? They shouldn't be stressed heavily, they're 2200uf 10V. I want to recap the entire thing, and I replaced that 4A rectifier with a 6A one

[goodpsusearch]

Re: How often do you guys do a preventative recap?

Since my Japanese caps are too big and it's just an L&C, do you think it's even worth replacing the YC caps with slightly used Teapo and OST caps? They shouldn't be stressed heavily, they're 2200uf 10V. I want to recap the entire thing, and I replaced that 4A rectifier with a 6A one

Make sure that the caps are not near a heat source like a resistor, that the fan is cooling effectively the psu and of course avoid to put non japanese caps on the 5vsb line. Almost forgot, NEVER use 85Celsious caps.

You could also search the datasheets of the caps to check if they are low esr or general purpose. Don't use general purpose even if they are 105C rated.

[mariushm]

Re: How often do you guys do a preventative recap?

I don't see any point in replacing the 4A rectifier, you won't draw more than 3A or so on that... and I doubt

In old design power supplies you will have resistors near each voltage rail, which load them with about 0.1-1 watts usually.

Here they are on your psu



Those designs need a minimum load to regulate and prevent oscillations and those resistors will get warm. You can bend them to be a bit further away but there's not much room there to put them away from the caps.
Maybe if you move the cables around so that the resistor core is further away... but they will still be covered by the cables so they won't be cooled by the fan.

You could just solder some cable in the holes where the resistors are soldered, put the cables through some heatshrink tube, solder the resistor to the cables and then heat up the heatshrink over the resistors to insulate them and glue the resistors to the metal case .. now they should be far away from the capacitors.

The inductors may also be quite warm but there's not much you can do about it.

[goodpsusearch]

Re: How often do you guys do a preventative recap?

I didn't notice these filter coils getting warm until now. The toroid ones can get very hot though.

[Pentium4]

Re: How often do you guys do a preventative recap?

Yeah I try to bend them farther away. So, you think the YC's can handle the heat?

[jsmoke]

Re: How often do you guys do a preventative recap?

never done a preventative recap, although I am a big fan of "If it ain't broke, fix it!".

[lti]

Re: How often do you guys do a preventative recap?

never done a preventative recap, although I am a big fan of "If it ain't broke, fix it!".

I agree, especially if it is new or is still under warranty. I don't see why anyone would recap a new device before they even test it to see if it works.

[momaka]

Re: How often do you guys do a preventative recap?

I don't see any point in replacing the 4A rectifier, you won't draw more than 3A or so on that... and I doubt

I agree.
Considering most computers don't draw more than 200W under max load, there probably won't be more than 2A going through that bridge rectifier.

Those designs need a minimum load to regulate and prevent oscillations and those resistors will get warm.

They do indeed, but I have been changing them on many of my power supplies. In fact, the edited pic you posted is of my 250W Deer PSU. In that PSU, I actually changed the minimum load resistors with slightly higher resistance ones because the old ones were producing so much heat that they were carbonizing the output wires.

This is what that PSU had before:
3.3V rail: 10 Ohm 2 Watt (~1.1 Watts dissipation)
5V rail: 47 Ohm 1 Watt (~0.53 Watts dissipation)
12V rail: 100 Ohm 2 Watt (1.44 Watts dissipation!!!)

Those resistors got so hot that even the PCB started to darken a bit. So this is what I changed them with:
3.3V rail: 47 Ohm 1 Watt (moved from 3.3V rail)
5V rail: 270 Ohm 1/2 Watt (IIRC) (notice how high I went with this one - this is because the computer this PSU is powering is a Pentium 3 which puts a heavier load on the 5V rail than anything else)
12V rail: 2x 1 KOhm 1/2 Watt in parallel for 500 Ohm combined

Since this PSU is designed to get feedback mostly from the 5V rail and the 5V rail is always well-loaded with the CPU, the regulation was actually really good.

So all in all, you can remove/replace those resistors but you have to be careful that the PSU is properly loaded if you want good regulation.