Are those two caps bad?

[goodpsusearch]

Re: Are those two caps bad?

+3.3/+5V output filter caps, they were 2x 1000uF 10V 10x16mm, ripple 1100mA, ESR 50 or 85mOhm, replacement: YXJ 2200uF 10V 10x20mm, ripple 1400mA, ESR 46mOhm.

The esr could be lower, for example 0.035 - 0.040. Don't be afraid. They should have used low esr caps and higher capacitance in the first place!

About 12V this is perfect:
YXJ 3300uF 16V 12.5x25mm, ripple 2230mA, ESR 32mOhm

Don't worry about dimater of the cap, I'm sure it will fit! It doesn't have to touch the pcb and 25mm is not too tall for an ATX psu!

Use a wet sponge for cleaning the tip of the iron.

Putting some fresh solder on the old solder joint always helps!

You can also use some flux.

" And last, when I finished to use the iron tip, I let it cool down and put it away. Is this ok or should I wet it with solder before cooling it down?"
I try to do that everytime because it protects the tip from corrosion, but sometimes I am just too lazy...

[ResistEnt]

Re: Are those two caps bad?

+3.3/+5V output filter caps, they were 2x 1000uF 10V 10x16mm, ripple 1100mA, ESR 50 or 85mOhm, replacement: YXJ 2200uF 10V 10x20mm, ripple 1400mA, ESR 46mOhm.

The esr could be lower, for example 0.035 - 0.040.

Ok so what about this?
YXH 2200uF 10V 10x28mm, ripple 1910mA, ESR 31mOhm.

Thanks for suggestions.

[goodpsusearch]

Re: Are those two caps bad?

That will do!

[ResistEnt]

Re: Are those two caps bad?

Uff guys the time runs too fast!
Still very busy and unable to proceed atm...

Anyway I ordered from Distrelec, capacitors are now at home

I had to choose some caps different from what I wrote above, since Distrelec wasn't selling them, but I stayed on known brands (Rubycon, Nichicon and Panasonic). Now I just have to do the work.

I'll let you know as soon as I'll find the time to make it.
Meanwhile, I take the opportunity to thank again all of you who supported me.

Bye.

[ResistEnt]

Re: Are those two caps bad?

Finally,
with the next week I should be able to do the soldering job.

I still have three more questions for you.

1. +12V output filter cap, it was a single capacitor of 1000uF ESR 39mOhm.
   You told me to replace that one with a 3300uF, but unfortunately I haven't found a perfect replacement from Distrelec. The order is done, I have all caps at home and of course I'd like to avoid placing a new order (mainly for shipment taxes). For the doubt, I bought all these possible replacements:
   (a) 1000uF ESR 38mOhm
   (b) 1500uF ESR 20mOhm (too low?)
   (c) 2200uF ESR 20mOhm (too low?).
   Brands are Rubycon for 1000 and 2200, Panasonic for 1500uF. Which one would you use?
2. Can I try the PSU, after replacing caps, without connecting it to the motherboard? I searched the net and found that it should be sufficient to short-circuit the green wire and a black wire to the connector. Do I have to remove the short right after the PSU boots up or has it to stay on the connector? I also read that the PSU should be under load, can I simply connect it to an empty hard disk?
3. About the sewing needle, is there a particular reason why the solder won't adhere to it? After all, it's stainless steel so it's not covered by oxyde. What am I missing?

Thanks, I'll let you know.
Bb.

[goodpsusearch]

Re: Are those two caps bad?

1. (c) 2200uF ESR 20mOhm (too low?).
Out of curiosity what are the series of those caps?

2. Yes, you can connect it to fans, DVD-Rom drivers, old/broken HDDs and old motherboard

3. It's stainless steel. Stainless steel and solder don't do well together!

[ResistEnt]

Re: Are those two caps bad?

Wow, very quick reply!

1000uF is a Rubycon ZLJ.
1500uF is a Panasonic FR type A.
2200uF is a Rubycon YXH.

Ok so the point is "steel", not "stainless"

[ResistEnt]

Re: Are those two caps bad?

I soldered the new caps in.

Apart from the too high temperature of the tip (I don't have a temp-controlled iron) and the consequent carbonized flux residues I removed from the board, the joints look good to me and also the soldering process was quite straightforward.

But before replacing the PCB in its case and solder the mains connector, I checked the voltage filter outputs for possible short circuits.

I found just 20 ohms between the ground and 3.3V, is this normal?

[goodpsusearch]

Re: Are those two caps bad?

That's the minimum load resistor that your multimeter sees. It's on the low side, meaning that it is going to generate a lot of heat and that heat reduces the caps lifetime. Many members here (for example, momaka, Pentium4 etc) change those resistors with higher values in order to reduce heat and improve efficiency.

[malikbilalahmad]

Re: Are those two caps bad?

First of all you should have change this blasted capacitor 1500uf/6.3v i hope your problem will solve

[ResistEnt]

Re: Are those two caps bad?

Good news!

I soldered the new caps and the mains connector, now the PSU is up and running

I first attached it to the wall plug, turned the back switch to the "I" position and measured the +5VSB voltage. Weirdly, it was below 3V and wasn't stable at all.

Then, I attached some loads (one HDD, one DVD player and one DVD burner) and remeasured the +5VSB voltage: it now was stable and equal to 5.05V.

I short-circuited the PS_ON signal and the PSU started. I measured all voltage rails and it took some time to see stable values, that now seem to be maintained:

• -12V: -11.62
• -5V: -4.97
• +3.3V: 3.41
• +5V: 5.15
• +5VSB: 5.05 (even if no load is applied)
• +12V: 12.12
• PS_ON signal when PSU off: +4.93V

I then attached all things, mainboard, another HDD, a FDD and the video card, pressed the Power On button on the case but nothing happened.

I disconnected anything but the initial load (HDD+DVD) and connected one thing after the other, trying to boot up anytime.
I think the problem was with the video card, since the three times I attached it I found three different behaviours:

1. the PC didn't boot at all;
2. the PC booted up but stopped after POST, no warning sounds, monitor off;
3. the PC booted regularly.

What I did between the three situations has been to clean the video card with compressed air, to clean the AGP connector on the mobo, to try with a second -PCI- video card.

... and I still have to replace the bad cap on the video card!

I tried the PC yesterday evening and this morning, it seems ok now.
Don't know if it'll be next week or the following, I just have to try repairing the video card now yup

Thanks again for your support, I'll let you know.

P.S.: is it normal that voltages, just after the first connection of the PSU to the wall plug, were not at the nominal values? Is this ever happened to any of you too?

Bye bye.

[ResistEnt]

Re: Are those two caps bad?

Here we are!

Last week I desoldered those damn Sacon caps from the video board, and replaced them with Panasonic caps.

The PC is running fine since then, and the message "The video card is not receiving sufficient power" does NOT appear anymore!

I deduce all went ok.
Thanks to all of you.
See you next time, bye bye.

[TechGeek]

Re: Are those two caps bad?

YaY!!!