Question about replacing a capacitor and component ID

[jpyerry]

Alright guys, I apologize for the newbie like questions here, but here goes:

I am trying to repair the board of an APC Smart-UPS 1500 that I recently acquired.

Firstly, the largest capacitor on the board is a 40V 2700uF 3 pronged snap-in style capacitor, Jianghai brand CD298 series. I've read that this brand is somewhat dubious quality, so I would like to replace it with something higher quality. But, I've been unable to source a replacement 3 pronged snap-in capacitor of similar specifications, so I am wondering if there is any intrinsic reason that I would have to use a snap-in capacitor? It seems like something along the lines of a Nichicon HE capacitor would easily exceed the specifications of the existing capacitor (and be considerably smaller), but isn't available as a snap-in capacitor, let alone a 3 pronged version. So, is there any intrinsic reason that I must use a snap-in capacitor, are capacitors simply snap-in for mechanical stability reasons, if so, I could probably shore up any mechanical instabilities with a healthy amount of silicone-rubber?

Next, I am having a hell of a time finding information on some of the chips on the board. There are 4 smallish transistor looking devices on the board. They have 3 leads, maybe 3-4mm square in shape, they are branded ST, and have the following writing on them:

MRC
D5NE
10
30A402

I have typed every possible combination of these letters and numbers into google and searched the ST website using every combination as well, and I've turned up absolutely nothing on them. I'd love to get a datasheet on them, but if that is unavailable, just knowing what they do would be fine too. I would have posted a picture of them, but using my cheap Nikon Coolpix camera, I've been unable to get a clear picture of them, I think I would have to use a manual SLR with a macro lens to capture them accurately.

Any help or advice on either of these problems would as always be most welcome.

Thanks,
Justin

[mariushm]

Re: Question about replacing a capacitor and component ID

Are you sure it's only 40v and not 400v ?

3 pronged, snap-in style capacitors are usually used for 100v+ capacitors. If it's really low voltage, perhaps they used snap in due to vibrations or something.
Either way, for just 40v capacitor, you could probably safely use any radial capacitor.

As for chips on board, it would have helped if you said the designators on the pcb for those chips.. as in q103 or something like that.

Here's a few service manuals, they're not exactly for smart ups 1500 (well one claims to be) but I suspect the 1500 model is similar to 1400 and possibly 1000 as well



(this one's in russian or some language that uses that alphabet but schematics might help)

Save them to your pc because i'll delete them in a few days.

See if the schematics look like your apc.

[jpyerry]

Re: Question about replacing a capacitor and component ID

Are you sure it's only 40v and not 400v ?

3 pronged, snap-in style capacitors are usually used for 100v+ capacitors. If it's really low voltage, perhaps they used snap in due to vibrations or something.
Either way, for just 40v capacitor, you could probably safely use any radial capacitor.

As for chips on board, it would have helped if you said the designators on the pcb for those chips.. as in q103 or something like that.

Here's a few service manuals, they're not exactly for smart ups 1500 (well one claims to be) but I suspect the 1500 model is similar to 1400 and possibly 1000 as well



(this one's in russian or some language that uses that alphabet but schematics might help)

Save them to your pc because i'll delete them in a few days.

See if the schematics look like your apc.

Thanks for the quick reply!

Yes, I am quite sure it is 40V, I've included a picture for you.

The unknown components are indeed marked Q11, Q18, Q22, and Q23. I actually managed to snap a semi-clear photo of them, boxed in in red. I got lucky just now.

As for the schematics, I appreciate them, and I've downloaded them, but I am about to go to bed now and will be travelling out of the area for my sister's wedding tomorrow, so I won't be able to study them until after the weekend. But, I will let you know if they are close to what I have.

Thanks,
Justin

[Khron]

Re: Question about replacing a capacitor and component ID

Those components are indeed transistors (MOSFETs, to be exact), STD5NE10 (ST omit the beginning of the part number, since it's virtually their logo ) in IPAK casing.



And regarding the big capacitor, i've seen 3-prong versions in datasheets of Panasonic snap-in caps.

[LLLlllou]

Re: Question about replacing a capacitor and component ID

Thanks for the quick reply!

Yes, I am quite sure it is 40V, I've included a picture for you.
Thanks,
Justin

Assuming you have space for 18mm diam.:

http://www.digikey.com/product-detai...1624-ND/756140

or if you only have room for 16mm:

http://www.digikey.com/product-detai...963-ND/3664384

Both have 7.5MM lead spacing.

[PeteS in CA]

Re: Question about replacing a capacitor and component ID

Digi-Key should carry snap-in parts from multiple good quality vendors - Panasonic, Nichicon and United Chemicon. The part you have is three prongs to improve mechanical stability - it's relatively tall for its diameter.

Jiang Hai quality aspires to mere mediocrity. My first and only encounter with their parts was some years ago. My manager handed me an unopened box that he said were samples for testing (what we did is another story). The box stunk, like dead fish! I opened the box and found an even more malodorous sealed bag of samples. The caps did not do well in our test, though venting left the parts smelling less awful. These parts were a low impedance series, allegedly similar to Nichicon HE, not a snap-in series like what you have. Back in the mid-late 00s Rifa was selling Jiang Hai parts, so that may be why APC used them.

[tom66]

Re: Question about replacing a capacitor and component ID

The third prong is usually tied to the positive or negative and acts as a mechanical support for the capacitor.