Replacing a 200V 1200µF Cap in a SMPS

[EasyGoing1]

So I have a Parallax 7355 RV SMPS, and it accidentally got plugged into 240V AC (kinda my bad...) Anyways, I found this link on Google, and the photos in that link look exactly like my board - burn marks and all. The only difference is, the cap that is closest to the bridge rectifier blew. I don't have a 200v 1200uF cap. I DO, however, have a 200V 680uF cap.

Looking at the bottom of the board, it looks like one cap connects from the input of the rectifier to ground, the other connects the output of the bridge rectifier to ground, so it looks like it's just conditioning the voltage.

My question is, would I potentially be causing any problems by using the 680uF cap, or should I just be patient and order the right one?

Thank you,

[Drassh]

Re: Replacing a 200V 1200uF Cap in a SMPS

Hello, someone correct me if i'm wrong but I have learned, that when replacing a cap, the voltage can be higher than the original but not lower. In the uF area it would have to be the same. So my guess would be to wait for the right one. ^.^

-Drassh

[EasyGoing1]

Re: Replacing a 200V 1200uF Cap in a SMPS

Hello, someone correct me if i'm wrong but I have learned, that when replacing a cap, the voltage can be higher than the original but not lower. In the uF area it would have to be the same. So my guess would be to wait for the right one. ^.^

-Drassh

I'm kinda looking for a more educated answer than that... perhaps someone who knows for certain ... Since it's only conditioning power, I would think that a lower uF rating would be fine but I just want to make sure that I won't be doing any more damage to the unit by lowering the micro farads. I'm thinking that at worse case, the signal coming from the rectifier won't be completely flat, but later on down the line it will get more regulation so it might be OK ... I'm just not 100% certain.

[eccerr0r]

Re: Replacing a 200V 1200uF Cap in a SMPS

depends on how much power you're drawing from the capacitors in the dead time. If you're not drawing much current, for now you probably temporarily can use a lower capacitance, unless they were depending on the higher capacitance for lower ESR.

So without knowing the circumstances, can't really tell...

[stj]

Re: Replacing a 200V 1200uF Cap in a SMPS

mains caps are expensive, i doubt they would have fitted 1200uf if they didnt need to.

[jiroy]

Re: Replacing a 200V 1200uF Cap in a SMPS

If you have another 680uF 200 v. (or 2 330 uF 200v, ) , you can put them in parallel .

[eccerr0r]

Re: Replacing a 200V 1200uF Cap in a SMPS

As an aside, I wonder how often these 120V-240V mishaps happen...
I have a 1200uF 250V capacitor that was a pull, and I see a telltale marking on it that something nearby gave up the magic smoke, and I wonder if this was pulled from a device that's the same as the one discussed here that too had suffered the same fate...

[EasyGoing1]

Re: Replacing a 200V 1200uF Cap in a SMPS

As an aside, I wonder how often these 120V-240V mishaps happen...
I have a 1200uF 250V capacitor that was a pull, and I see a telltale marking on it that something nearby gave up the magic smoke, and I wonder if this was pulled from a device that's the same as the one discussed here that too had suffered the same fate...

Well ... It would only happen if someone wasn't paying attention - and they made their own adapter to convert a 240V 30A twist lock down to a weird Y shaped three pronged 110V 20A connector and somehow managed to get both 110V legs from the twist lock onto each prong of the Y plug and didn't check it with his meter before using it on the RV ... I'm not naming names of course (*cough* me *cough*) ... but it COULD happen to anyone I'm sure ....

[stj]

Re: Replacing a 200V 1200uF Cap in a SMPS

i saw a few systems blown to hell back in the early days when people build there first system and didnt check the selector-switch on the psu before plugging it in!!!

never assume it's set to your voltage when new!!

[eccerr0r]

Re: Replacing a 200V 1200uF Cap in a SMPS

Now it makes me paranoid to always carry a multimeter with me, just to ensure arbitrary outlet's voltage is what it should be...

[EasyGoing1]

Re: Replacing a 200V 1200uF Cap in a SMPS

Now it makes me paranoid to always carry a multimeter with me, just to ensure arbitrary outlet's voltage is what it should be...

So ... I actually had to make a converter to convert from a 240 plug to a 110 plug and I used a diagram that I found online to wire the two ends together. The green was obvious, and the black was opposite of the green, but the white wire was supposed to be connected to the left side of the plug which would have just given me 110, but I read the diagram backwards. It was a mirror image thing and I didn't see it spacially in my head properly and I was in a hurry ... so I thought I had it right, but what I ended up doing was connecting the white AND the black to 110 leads giving me 220. Had I done it correctly, it would have been all good. I should have checked my work with the meter. Normally I wouldn't be checking for proper voltage if I were using manufactured cables, but in my case, they don't make the cable I needed ...

I ended up ordering the parts I need. Supposed to be here yesterday but so far, no parts.

[kc8adu]

Re: Replacing a 200V 1200uF Cap in a SMPS

its pretty common for me to see rv converters blown up like this.
i bet the warranty claims from accidents offset the cost of designing the unit for wide input.
you can try the smaller caps for a quick test and order the correct ones if it checks out.

[jazzie366]

Re: Replacing a 200V 1200uF Cap in a SMPS

So I have a Parallax 7355 RV SMPS, and it accidentally got plugged into 240V AC (kinda my bad...) Anyways, I found this link on Google, and the photos in that link look exactly like my board - burn marks and all. The only difference is, the cap that is closest to the bridge rectifier blew. I don't have a 200v 1200uF cap. I DO, however, have a 200V 680uF cap.

Looking at the bottom of the board, it looks like one cap connects from the input of the rectifier to ground, the other connects the output of the bridge rectifier to ground, so it looks like it's just conditioning the voltage.

My question is, would I potentially be causing any problems by using the 680uF cap, or should I just be patient and order the right one?

Thank you,

I'm gonna say definitely get the right cap. You can go up in voltage as much as you like, but unlike on the output of a SMPS you can't fuck with the capacitance too much. I'd say keep it @ 1200uF and if you want to insulate yourself from this again, you could step it up to 400V. However I'd say let's try not to do this again and just replace it with the proper cap. If you want 10 of the caps that you need for cheap, here's a good seller: http://www.ebay.com/itm/NEW-Lot-of-1...QAAOSwTY9ZX9bM It claims to be local pickup only, but for some reason that's only when I go to the actual page of the listing, it advertises shipping when viewed from eBay's search. If I were you I'd ask about shipping, even if it was 15$ in shipping, it's worth it.
For those who are going to bitch about it being 85C, yeah I know I know, it's NCC though, so there shouldn't be the slightest of problems.