help IDing a Diode from a charger.

[skeletor]

so I went and plugged an align pack into my charger and it smoked, I pulled the pack and it appears to be ok.. the charger did not fare so well, it's a common sense RC balance charger BTW.

in the pic you can see D23 on the right melted the solder and fell off, D26 let the smoke out and D27 on the left started to melt the solder.

The board has it marked as a diode and it is marked "SK 34".. does anyone know what it is and where I could get one to replace this with ? I don't care if it's not a surface mount component, any replacement will do, preferably something I can pickup at the local radio shack..

thanks,
rich.

[plane_spotter]

http://download.siliconexpert.com/pdfs/2004/08/25/semi_a/1/dds/ds/ds13006_r8.pdf

YOU MAY BE ABLE TO CROSS REFERENCE FOR A STANDARD LEADED PART.

GOOD LUCK

[RC-Tester]

An International Rectifier 30BQ100 Schottky will *exceed* the specs required in an identical package. Should be available from Mouser etc.

HTH

Rod

[skeletor]

thanks Plane Spotter and RC-Tester, I ordered a couple of 30BQ100's from Mouser.

rich.

[dleroi]

thanks Plane Spotter and RC-Tester, I ordered a couple of 30BQ100's from Mouser.

rich.

Not to be a nudge, the IR part should certainly work. but why didn't you replace it with the original part (SK34)? They're common and also available from Mouser, Digikey, etc.

[Dan Baldwin]

Not to be a nudge, while it's possible that the only damage done to the charger was the diodes, it's not likely.

Do you know what caused the charger to smoke? Pack hooked up backwards?

Dan

[Dan Baldwin]

Here I am being a nudge again

Mouser doesn't show 30BQ100's in their catalog, rather they suggest 512-S310 as a replacement. The original SK34 is a 40 volt schottky diode with a forward voltage drop of .5 volts at 3 amps. the 512-S310 is a 100 volt schottky with a forward drop of .85 volts at 3 amps, so it will be less efficient, and run hotter.

Dan

[RC-Tester]

Here I am being a nudge again

Mouser doesn't show 30BQ100's in their catalog, rather they suggest 512-S310 as a replacement. The original SK34 is a 40 volt schottky diode with a forward voltage drop of .5 volts at 3 amps. the 512-S310 is a 100 volt schottky with a forward drop of .85 volts at 3 amps, so it will be less efficient, and run hotter.

Dan
If you are in Euroland RS stock the 30BQ100 as 254-0695

HTH

Rod

[Probedude]

Not to be a nudge, while it's possible that the only damage done to the charger was the diodes, it's not likely.

Do you know what caused the charger to smoke? Pack hooked up backwards?

Dan

Must have been. Those diodes are on the secondary side of the transformer. Hooking the battery up backwards forward biases that schottky and shorts the battery through the transformer winding.

The rest of the charger may be just fine - unless there are some tantalums on the secondary that saw reverse potential. Tantalums HATE that!

[skeletor]

yes, I plugged in an Align pack which has the same plug but wired differently so it smoked, I am usually more careful about stuff like this but not this time. it was only in for a few seconds. everything else looks fine and it powers up.. I am willing to try a couple of 96c diodes to see if it can be salvaged :) doesn't look like there are any tantalum caps in there. there are a couple of other SK34's on the input side so I'm going to do a swap with the 512-S310's.. if it get's hot I suppose I can always replace them with 1N5822's

thanks all,
rich.

[dleroi]

there are a couple of other SK34's on the input side so I'm going to do a swap with the 512-S310's.. if it get's hot I suppose I can always replace them with 1N5822's

thanks all,
rich.

Rich,

I still don't understand why you are looking for substitutes for the SK34s, when SK34s are available from the same places as the substitutes are. Are you thinking they are hard to find?

- Don

[Probedude]

yes, I plugged in an Align pack which has the same plug but wired differently so it smoked, I am usually more careful about stuff like this but not this time. it was only in for a few seconds. everything else looks fine and it powers up.. I am willing to try a couple of 96c diodes to see if it can be salvaged :) doesn't look like there are any tantalum caps in there. there are a couple of other SK34's on the input side so I'm going to do a swap with the 512-S310's.. if it get's hot I suppose I can always replace them with 1N5822's

thanks all,
rich.

Don't both fixing the input side - as you said it powers up fine.

[skeletor]

Rich,

I still don't understand why you are looking for substitutes for the SK34s, when SK34s are available from the same places as the substitutes are. Are you thinking they are hard to find?

- Don
Originally I just asked for something to replace the burned out SK34 with, and not knowing my way around suppliers like digikey and mouser is why I asked here. I did the obligitary google searches for SK34's but all I got were datasheets so I didn't think I would be able to find them. I did not state that I was looking for a substitute part, all I wanted was to get my charger running again in the shortest time frame. For some reason I just ran with what was suggested by RC-Tester.

well, the 512-S310's arrived yesterday and I pulled one of the SK34's from the input side and replaced the fried one. the one that melted the solder and fell off still worked so there are 4 SK34's on the output side of the charger (it only charges up to 4S), and one SK34 and one 512-S310 in parallel on the input side.

It works :) :) I charged a bunch of packs last night which means I can go fly again today..


thanks everyone,
rich.