Dell used to be really good quality....

[mockingbird]

Re: Dell used to be really good quality....

Because there just there to link two circuits together. It could be a jumper wire instead.

Some of the caps will be Low ESR, some will be general purpose. The best thing is to traw a diagram of all the wiring, then desolder the wiring to get the PCB free, and then mark, measure, and identify all the caps.

List them here along with the series and I will tell you what to get.

As for my preferences, I like UCC the best.

[PCBONEZ]

Re: Dell used to be really good quality....

ASUS has been doing full board polys for the majority of their boards for about 2 years...just saying.

And screwing it up.... just saying.

[PCBONEZ]

Re: Dell used to be really good quality....

I think I can get the right replacements. But Low-ESR, High Ripple Current? Any series you like in particular? Almost anything has to be better than this crap.

I think I'm going to do a full recap...

Are coupling capacitors electrolytic? And what is the reason behind not replacing them?

Thanks for all of the help.

Coupling caps don't work very hard.
All they do is pass a signal through them while blocking the DC.
Signal current is tiny compared to Ripple current.
.

[PCBONEZ]

Re: Dell used to be really good quality....

On the 'beer can' cap that looks to have a bloated top.
The top has a plastic disc on it that is held in place by the sleeve.
- It's there as electrical insulation.
Sometimes the discs will bow up even though the cap under it has not bloated.
Push down on it with your finger to see if the cap under it is actually bloated or not.
[With the thing de-energized of course!]
.

[TheLaw]

Re: Dell used to be really good quality....

Coupling caps don't work very hard.
All they do is pass a signal through them while blocking the DC.
Signal current is tiny compared to Ripple current.
.

So replacing the coupling caps would be bad? I mean...if I replace value for value, how could it go wrong? Or is it ESR specific or something...

[TheLaw]

Re: Dell used to be really good quality....

Because there just there to link two circuits together. It could be a jumper wire instead.

Some of the caps will be Low ESR, some will be general purpose. The best thing is to traw a diagram of all the wiring, then desolder the wiring to get the PCB free, and then mark, measure, and identify all the caps.

List them here along with the series and I will tell you what to get.

As for my preferences, I like UCC the best.

What do you mean of the "wiring"? When I recap, I draw a quick diagram of the PSU and mark the value of each cap. Then I desolder them all and replace them.

I'm not home right now, but I'll do so tonight.

Is there any reason why I can't use Low ESR for all of them?

[mockingbird]

Re: Dell used to be really good quality....

When you try and take out the PCB (Because you have to get at the underside to desolder the caps), you'll notice the wires connected to the power socket and possibly voltage selector switch are a hinderance. You should desolder those from the PCB so that you can freely move about with only the PCB. It will make the job a lot easier.

[TheLaw]

Re: Dell used to be really good quality....

When you try and take out the PCB (Because you have to get at the underside to desolder the caps), you'll notice the wires connected to the power socket and possibly voltage selector switch are a hinderance. You should desolder those from the PCB so that you can freely move about with only the PCB. It will make the job a lot easier.

Dell actually made it easy...or rather Hipro did.

The IEC socket's wires go into a socket on the board. So all I had to do was pop the socket.

The voltage selector switch was screwed in, so all I had to do was unscrew it and it easily came out.

So I have PCB out. There are about 18 electrolytics on the board. However, about 9 of those are tiny values, like 1uF-47uF. So are these the coupling capacitors you speak of? It would seem like a pain in the but to replace even these. If it is necessary, I'll do it, but...

Anyway. Here are the values of the big capacitors. Not the smaller ones. I'm assuming they are pretty unimportant.

6x G-Luxon 2200uF @ 10V
1x G-Luxon 2200uF @ 16V
1x Teapo 220uF @ 35V
2x Teapo 330uF @ 200V


Not too many caps really, but then again, I think it's like a 120W PSU or something.

I'm doing a big order of Mouser soon for another project so I'd prefer they were sourced from there. It seems UCC KY are out of stock on Mouser though...

Thanks a bunch.

[PCBONEZ]

Re: Dell used to be really good quality....

So replacing the coupling caps would be bad? I mean...if I replace value for value, how could it go wrong? Or is it ESR specific or something...

No, it's not bad to replace them.
Just trying to explain what they are.

These are usually going to be 22uF or less and 4mm or 5mm caps. [On Mobos & in PSUs at least]

Regardless of uF, not every 4&5mm cap is a coupling cap.
There are some other uses. You can't tell what it's doing there without tracing the circuit and drawing out the schematic. That's a little bit too much work for what it's worth to know exactly what the cap does. Most of the time they ARE coupling caps, but not always.
- In discussion "Coupling Caps" has come to mean small uF 4&5mm caps - even if they aren't actually coupling caps.

If they are 85C caps it's a reasonable preventative measure to change them to 105C caps in anything that gets hot.

[With what is coming, bear in mind that it's -unusual- for coupling caps to go bad and most people don't even look at them, let alone change them.]

They cause occasional problems on Intel made boards all the way back to socket 370. Some of those have small 4&5mm 85C caps that go bad [and may or may not bloat] sometime after about 5 years old. Time to failure depends on actual operating hours of the PC and how hot it is inside the case.

Also these are the ones that cause problems in Dell 620 mini-cases. [Long thread on that somewhere.] The case configuration puts them right next to a hot HDD and they fry after a while even if rated for 105C.

Someone [you will need the Way-Back machine to find this thread] found some bad ??22uF OST's in the chipset area and it was 'killing' the Vtt voltage entirely. As I recall it was an Asus board but I can't remember who posted the thread. [I suspect many of the Asus 'mystery failures' are due to cheap 4&5mm caps. Few people check those caps even when the board won't work so the problem never gets found.]

So: YES, they do go bad now and then..

In PSUs I replace them just because opening up PSUs far enough to change caps is a PITA and I don't want to do it twice.

--
They often aren't low ESR [and usually don't need to be] but it doesn't hurt to use 'entry level' low ESR caps.
I'll usually use something like LXZ, FC, KG or PW for those.
.

[mockingbird]

Re: Dell used to be really good quality....

According to what PCBONEZ is saying, I would recommend replacing ALL the caps. why not, you already have the thing opened.

Can you list also series and diameter of the caps (Height is less imoprtant than width) in mm? This would help me nail an exact replacement from Mouser.

If you're going with Mouser, forget about using UCC exclusively. We'll probably need to go with a mix of Nichicon/Panasonic/UCC. They even have a limited stock of Rubycon if you're prepared to pay a little extra.

[TheLaw]

Re: Dell used to be really good quality....

Alright. I have to be out so I'll make this quick. I've tried to get my measurements as close as possible. There's usually around 1-2mm leeway on every capacitor anyway, so don't fret too much.

6x 2200uF @ 10V-10mm
1x 2200uF @ 16V- 10mm
2x 330uF @ 200V- 22mm
1x 220uF @ 35V- 7mm
1x 22uF @ 16V- 5mm
2x 47uF @ 16V- 5mm
1x 2.2uF @ 50V- 5mm
1x 1uF @ 50V- 4mm
1x 0.47uF @ 50V- 4mm
1x 10uF @ 16V- 5mm
1x 4.7uF @ 50V- 5mm
1x 6.8uF @ 50V- 5mm
1x 47uF @ 50V- 6mm

I'll pay for whatever is good, but honestly, I doubt I'd see a difference between Nichicons/Pannys and Rubycons because this computer is already ancient and it probably won't get much use anyway. But whateverrr....

Thanks a bunch.

[TheLaw]

Re: Dell used to be really good quality....

Wait, Mouser doesn't stock Rubycon, do they?

The reason I am hesitant to do the small ones is because I've had some bad experiences desoldering super small components off mediocre quality boards. I've gotten better, but there's always that chance that I lift a pad, and I'm doomed. I mean...I could run a jumper wire, but that's ugly.

[mockingbird]

Re: Dell used to be really good quality....

Power supplies are easier because they're ususally only one layer. Listen, you did a good job listing the caps, but we really need the series to differentiate the GP caps from the low ESR caps.

Oops I meant NEwark. Newark has some stock of Rubycon, not much, but some.

[TheLaw]

Re: Dell used to be really good quality....

Power supplies are easier because they're ususally only one layer. Listen, you did a good job listing the caps, but we really need the series to differentiate the GP caps from the low ESR caps.

Oops I meant NEwark. Newark has some stock of Rubycon, not much, but some.

Oh sorry. I forgot about series. It's going to be rough. The G-Luxon labels are pretty crappy. I'll do my best. Especially on the tiny ones.

[TheLaw]

Re: Dell used to be really good quality....

Phew!

6x 2200uF @ 10V-10mm....G-Luxon "HM" @ 105C
1x 2200uF @ 16V- 10mm....G-Luxon "HM" @ 105C
2x 330uF @ 200V- 22mm....Teapo "LXK" @ 85C
1x 220uF @ 35V- 7mm....Teapo "SEK" @ 105C***
1x 22uF @ 16V- 5mm....G-Luxon "SM" @ 105C
2x 47uF @ 16V- 5mm....G-Luxon "SM" @ 105C
1x 2.2uF @ 50V- 5mm....Teapo "SS" @ 105C
1x 1uF @ 50V- 4mm....Teapo "SS" @ 105C
1x 0.47uF @ 50V- 4mm....G-Luxon "SX" @ 105C
1x 10uF @ 16V- 5mm....G-Luxon "SX" @ 105C
1x 4.7uF @ 50V- 5mm....G-Luxon "SX" @ 105C
1x 6.8uF @ 50V- 5mm....G-Luxon "SX" @ 105C
1x 47uF @ 50V- 6mm....G-Luxon "SM" @ 105C

***This one is hidden behind two ICs. It's really hard to see. On first glance I saw "GEK" but after googling, I can only find "SEK". It looks a hella lot GEK, but I'm thinking it's SEK.

Just a note.

I'm going to come up with my own list as well and see if I'm on the right track.

[02502536]

Re: Dell used to be really good quality....

hey guis i hab had dell for 14 years no problems and i justbought a car that my friend put a dell computer in its great

[TheLaw]

Re: Dell used to be really good quality....

hey guis i hab had dell for 14 years no problems and i justbought a car that my friend put a dell computer in its great

Troll?

[mockingbird]

Re: Dell used to be really good quality....

1) 10v 2200uF Samxon "GT" 10x20mm (Big Joe)
2) 16v 2200uF Samxon "GT" 10x25mm (Big Joe)
3) 200V 330uF UCC "KMH" 22mmx30mm (Mouser)
4) 35V 220uF UCC "KMG" 8x11.5mm (Mouser)
5) 16V 22uF UCC "KMG" 5x11mm (Mouser)
6) 16V 47uF Nichicon "KT" 5x11mm (Mouser)
7) 50V 2.2uF Nichicon "ST" 4x7mm (Mouser)
8) 50V 1uF Nichicon "SV" 4x7mm (Mouser)
9) 50V 0.47uF Nichicon "SV" 4.7mm (Mouser)
10) 16V 10uF UCC "KMG" 5x11mm (Mouser)
11) 50V 4.7uF UCC "KME" 5x11mm (Mouser)
12) 50V 6.8uF Nichicon "VR" (Mouser)
13) 50V 47uF UCC "KMG" 6.3x11mm (Mouser)

Regarding the SEK... Yes, farily common Teapo general purpose series. The spec sheet even says that it can be used for "coupling, decoupling". I will simply match the ripple.

Note for the first two caps I point you two Big Joe. These caps are very difficult to source at 10mm. True the owner of this site (TopCat) stocks Samxon GC and GD for this rating but GD and GC have too low an ESR. GT is perfect however. Newark *may* have a Panasonic FK part that would suit you here. (If you can fit a 12.5mm cap in place, let me know so you can place the whole order at Mouser).

Are you sure 12 is 6.8uF and not 0.68uF?

[Scenic]

Re: Dell used to be really good quality....

Big Joe? Big Pope? ...?

[TheLaw]

Re: Dell used to be really good quality....

It is 6.8uF.

I did some measurements. I think 12.5mm would be fine. It would be very tight, but I can do some manipulating and it should work fine.

Thanks for the indepth list!