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Electronics experts...need your help in identifying a component :-)

txshan130

Well Known Member
Posted this in classifieds last week trying to find some parts but now looking at repairing the board on my "smoked" MX-20. Please see pics below and let me know if anyone can identify the orange and silver component. I believe the one that burned up is an exact duplicate of the one that is still there...

The label above the one remaining component says "C27"...guessing it is some sort of capacitor???

Thanks in advance...

- Brian

See pics below (3rd pic shows closeup of part after burned residue was cleaned up)--->

https://www.dropbox.com/s/fkyvge83rl8niuz/IMAG7040.jpg?dl=0

https://www.dropbox.com/s/t059xpsfdbvdefs/IMAG7039.jpg?dl=0

https://www.dropbox.com/s/2hjpncyr51ufojr/IMAG7054.jpg?dl=0

And here I found a pic of it exactly....but still don't know specs

tant%20china%203.jpg
 
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Well, good luck trying to find a schematic or anything in the way of useful parts information about the MX20. That would be nice, but probably not going to happen.

Given its size and location, I would suspect it is part of a fairly high voltage inverter power supply for the CCFL screen backlight. When I see one like that rather spectacular example, it's almost always a safe bet that just replacing the capacitor will not fix anything. When they blow like that there is almost always another failed component that caused it to do a spontaneous solid-to-vapor phase change, or one that has failed because the cap shuffled off its mortal coil.

If your soldering skills and tools are sufficient, you might remove the other one to see if it's got markings on the bottom or not. That might be a place to start. At this point I wold say you have nothing to lose. If you could find the value of the missing part, you could replace it with an exact substitute or just tack-solder a thru-hole part in its place.
 
It's a surface mounted capacitor but you'd need to have the markings on it to know what the value of it was. You might contact Apollo and ask them what the part is or have them send you the replacement. Not very common for a capacitor like that to burn up, I would bet there's more wrong than just that part.
 
I may know some people who have the answer. If I find out anything I'll contact you offline.

mcb
 
Was the fried part similar to the orange cap? If so it looks like a Tantalum capacitor. Kemet makes some of those type I think.

Is the orange cap that remains (C27) in parallel with the part the burnt? You can check by ohming out the pads.

If you have verified that there is still not a short present by measuring across those pads then you can add a replacement part. Its not all that common for caps to short, but it does happen especially if they are under rated.


First you would need to measure the voltage across the pads when the circuit is powered up. That will tell you the minimum voltage rating of the replacement cap. Sometimes they are marked (for example 35V) and sometimes they have the capacitance marked also (for example 22uF). You can often tell based upon the package size of the cap the rating since there may only be a few options for value and rating in that size package. It doesn't look like the other orange cap has any markings though. So you may need to guess. I could help you make an educated guess if you find the family of parts.
 
Slow down

I may know some people who have the answer. If I find out anything I'll contact you offline.mcb

Switching type power supplies do not react well to guessing part values! Everything from radio interference to smoke could be the result.

With luck, Mike will get you the proper part number.
On the bright side, Most tantalum caps seem to fry from internal shorts so replacing it and possibly a fuse link may be all that's needed.
 
Thanks everyone for all the great info and help so far...keeping my fingers crossed to get some more info shortly. As mentioned above, nothing to lose because if I don't fix it, it will just be an expensive paperweight on my desk :)

BTW, I did call the Garmin/UPS AT folks who said they have never released repair/technical info on the MX20 and never will...but of course they were happy to offer up the idea of replacing it with a very expensive GMX-200...

Thx again for all the ideas and help.
 
Well actually its not rocket science. Evaluation of just a few parameters and that's it.

I would bet that if there isn't any other damage that it would operate as is if there is another cap in parallel. There would probably be more ripple but that would be it. I'd still suggest adding the parallel cap since ripple current may be a factor in the reason for having two in parallel in the original design.
 
Any luck

Hey. Any luck with diagnosing the problem? We have an identical problem with C28 burnt out. We're thinking of replacing the cap. Have you had any luck finding a replacement part?
 
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