LC Power Arkangel with bad caps

[Half-Saint]

Re: LC Power Arkangel with bad caps

Actually the biggest caps are 2200uF 16V, the rest are all smaller. Also not gonna bother with the smallest of Samxon GFs which aren't venting (yet) and seem to be fine. They're jammed between the heatsink and the cable spaghetti so very hard to replace. 2200uF 10V cap is 10mm, 1000uF 10V is 8mm so no problem there. All of this is available in FC.

[c_hegge]

Re: LC Power Arkangel with bad caps

You can use FC for the 10V caps, but you'll have to use FK for the 2200uF 16V caps, cince 2200uF 16V FCs are 12.5mm diameter, and won't fit.

[Agent24]

Re: LC Power Arkangel with bad caps

not gonna bother with the smallest of Samxon GFs which aren't venting (yet) and seem to be fine. They're jammed between the heatsink and the cable spaghetti

I would recommend you do replace them, even if it's difficult. Samxon GFs are known to be crappy, just because they are small and not bulging means nothing. If they are right next to the heatsink there is even more concern as they will have been getting more heat.

[Half-Saint]

Re: LC Power Arkangel with bad caps

You can use FC for the 10V caps, but you'll have to use FK for the 2200uF 16V caps, cince 2200uF 16V FCs are 12.5mm diameter, and won't fit.

This is what happens when you look at the specs instead of the actual cap... the specs for Samxon GF say 12.5x20 for 200uF 16V. What's up with that?

I would recommend you do replace them, even if it's difficult. Samxon GFs are known to be crappy, just because they are small and not bulging means nothing. If they are right next to the heatsink there is even more concern as they will have been getting more heat.

Can someone recommend an easy way of removing the heatsink together with MOSFETs or whatever those things are called

[mockingbird]

Re: LC Power Arkangel with bad caps

This is what happens when you look at the specs instead of the actual cap... the specs for Samxon GF say 12.5x20 for 200uF 16V. What's up with that?

That's the message we were trying to get across. Glad you caught it in time. Replace all the PSU caps.

Can someone recommend an easy way of removing the heatsink together with MOSFETs or whatever those things are called

You need solder wick for this. Just wick away the solder on the FETs, and there should be two pins on each side of the heatsink that need to be desoldered too. You shouldn't need to remove the heatsink to replace the caps in between them. Simple desolder the cap, clear the holes with wick, and put in the replacements - long leads and all. The long leads then allow you to maneuver it into the holes.

[Agent24]

Re: LC Power Arkangel with bad caps

This is what happens when you look at the specs instead of the actual cap... the specs for Samxon GF say 12.5x20 for 200uF 16V. What's up with that?

Probably custom order. Or sometimes they sell several sizes of the same capacitor, eg: skinnier but taller. If they do this will be in the datasheet.

If yours is not listed, just look through the datasheet to find other caps with the same can size as your ones, which will give you a close idea of what ESR and RCR yours will be.

[Half-Saint]

Re: LC Power Arkangel with bad caps

Probably custom order. Or sometimes they sell several sizes of the same capacitor, eg: skinnier but taller. If they do this will be in the datasheet.

If yours is not listed, just look through the datasheet to find other caps with the same can size as your ones, which will give you a close idea of what ESR and RCR yours will be.

Thanks guys for all the tips. I finally managed to desolder the rest of the caps, including the one hiding beneath the heatsink. I couldn't get to it without desoldering one of the toroidal ferrite coils. Now that all the caps are out (sans the really really small ones), I ordered everything else that I needed and now all I can do is wait and hope that the recap does the trick.

Thanks to you, I learned a few valuable lessons and even if it doesn't work after the recap, I have something to show for.

Cheers

[Agent24]

Re: LC Power Arkangel with bad caps

Some people say don't bother with the small ones, but I tried that and I would advise you do replace the small ones too, especially if they are startup capacitors. I was caught out on a Dell PSU that exhibited very strange symptoms that turned out to be dead startup capacitors.

[Half-Saint]

Re: LC Power Arkangel with bad caps

I was caught out on a Dell PSU that exhibited very strange symptoms that turned out to be dead startup capacitors.

I'm curious about how you came to that conclusion? It would probably never occur to me :-)

[Agent24]

Re: LC Power Arkangel with bad caps

I'm curious about how you came to that conclusion? It would probably never occur to me :-)

They were the only capacitors I had not tested or replaced, when I did replace them it powered up normally. When I tested them they had very high ESR.

I had originally been thrown off because it would start, run for several seconds (though without a power-good signal) but then go into a 'reboot loop' - so I thought it was something wrong with the output monitoring circuitry.

[Half-Saint]

Re: LC Power Arkangel with bad caps

I ended up replacing 9 caps and spent about 4 hours on the job:
3x 2200uF 16V
1x 2200uF 10V
4x 2200uF 6.3V
1x 1000uF 10V

but because of Farnell's MOQ I had to order 20 caps which ended up costing me 36€ with shipping.

I had quite a lot of trouble putting the new caps in place because of the wire spaghetti surrouding them. In the end I also got a nasty electrical shock while I was tucking in the PCB containing the connectors for modular cables while the PSU was still plugged in.

All in all, a precious lesson learned thanks to you guys :-)

Cheers

[goodpsusearch]

Re: LC Power Arkangel with bad caps

I think you should replace 3 small caps:

1x10uF 25V
2x220uF 25V
All of them are placed under the center heatsink.

When I tested the caps of the Thermaltake psus, they had too high esr and low capacity.

[goodpsusearch]

Re: LC Power Arkangel with bad caps

Just make sure that, after the recap, the "floating" transistor is not touching the heatsink! There is a transistor there that Channel well technology didn't attach to the middle heatsink. This thing is not insulated and it shouldn't make a contact with the heatsink.

[Half-Saint]

Re: LC Power Arkangel with bad caps

While I haven't replaced the small caps yet, I found another problem with the PSU. I tested the PSU with an old slot 1 motherboard and it seemed to work fine. However, when I tested it with a modern motherboard which uses an additional 4-pin 12V connector, the system wouldn't boot. Maybe I haven't used enough solder on 12V leads when I resoldered them to the PCB.. any other ideas?

[Agent24]

Re: LC Power Arkangel with bad caps

Did it power on at all? Or power on but no POST?

[Half-Saint]

Re: LC Power Arkangel with bad caps

It powers up but the screen remains black, CPU fan works and the hard drive spins up. No beeps.

[Agent24]

Re: LC Power Arkangel with bad caps

Do you get +5v on the POWER_OK pin? (Pin 8, grey wire)

Also, did it POST the system before you recapped it?

[Half-Saint]

Re: LC Power Arkangel with bad caps

Sorry for the late reply, was out of town since Wednesday.

Just tested the PSU with an old socket 370 motherboard which only has a 20-pin ATX connector and it booted up fine. I'm beginning to suspect my soldering of the 12V lines...

[Agent24]

Re: LC Power Arkangel with bad caps

It's possible if you did not make a good connection there is not enough power getting to the extra connector and the board cannot start, unfortunately the cables have a big thermal mass and require quite a lot of power to heat them up properly

[Half-Saint]

Re: LC Power Arkangel with bad caps

I figured out the reason why the board wouldn't start. The PSU being modular, I forgot to re-connect the 12V connector on the PSU side! It was attached to the main 24-wire cable with some zip ties and I didn't notice it wasn't connected to anything on the other end :-)