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Inverter damaged by leaking moisture absorber. Repairable?


Psycloud

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A few weeks ago our inverter started whistling like a boiling kettle.  It wasn't switched on (as we are on landline) but was connected the 12v system as per normal. I disconnected the inverter and discovered it was wet - upon further investigation it turned out that a moisture absorber in the cupboard above the one the inverter lives in had overflowed.  There were still crystals in the top section but the water container was completely full so it seems it can absorb more than it can hold.  It is similar to the one pictured below....

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I have opened up the inverter and had a look and can see 2 resistors that have corroded and a transistor that has gone pop.  I have cleaned out all the slimy water (contaminated with calcium chloride) which had managed to get inside and think I could make an attempt at replacing the resistors without too much trouble (they are pennies on eBay) however I'm unsure where to get a similar transistor as Google doesn't help with any of the numbers stamped on it (well it's neighbour). 

Can anyone please help identify a suitable replacement transistor? 

Many thanks

David

 

 

image2.JPG

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I think you have another leak above the moisture container as the crystals will only obsorb so much from the air so the container must have been getting its water from elsewhere, most likely a drip from above.

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Happy for a Mod to rename this to "overflowing". 

Yes I am aware they need to be emptied but this is the first time I've ever had one overflow so it's not uncommon to just deal with them when the crystals have disappeared.  On this occasion I had forgotten about this one - an expensive mistake possibly :(

Just now, Robbo said:

I think you have another leak above the moisture container as the crystals will only obsorb so much from the air so the container must have been getting its water from elsewhere, most likely a drip from above.

No leak from above.  The cupboard contains clothing and it was all dry.  The container was below the clothing.  I think it may be a case of the water capacity being too small for the amount of crystals provided.

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I think your transistor is made by Inpower Semiconductor (IPS) and is as marked.  

Try starting here for the spec and then look for an equivalent if you can not find an exact replacement  -  http://www.inpowersemi.com/en/product.aspx?KeyWord=ftp08n

Added  -  You could have had a look on ebay as you would have found this  -  http://www.ebay.co.uk/itm/100-New-And-Original-FTP08N06A-Transistor-TO-220-/182183314075?var=&hash=item2a6af8c29b:m:mBXRlhFUZTUYHu_5XkQP91w

or even this if you want lots of them - http://www.ebay.co.uk/itm/10pcs-FTP08N06A-N-Channel-TO-220-MOSFET-Transistors-/282448029367?hash=item41c336e6b7:g:H3YAAOSwE0JZAG7T

 

Added some more - There are probably some metal migration tracks which have caused the overload, so have a good look all over the board where it was wet, and give it a good brush with a stiff nail brush or similar to remove them.  Try not to remove any surface mount components whilst doing this.  If there are surface mount comps on the board, water will tend to wick underneath them so there may be shorts where you can not see, but hopefully not.  Best have a probe with your meter, but as inverters make high voltages make sure it is all disconected etc.

 

Edited by Chewbacka
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3 minutes ago, Psycloud said:

I think it may be a case of the water capacity being too small for the amount of crystals provided.

No - I think the reason that the 'tank' is removable, is so that you can empty it and 'replace it'.

It is designed (well - all the ones we have used) so that you get 2 or 3 'fills' from one lot of crystals.

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Water damaged electronics are generally 'beyond economic repair'. It is just possible that you'll replace a few obvious components and get lucky but I wouldn't hold out much hope. 

As it's also had calcium chloride in the water it needs to be thoroughly flushed with clean water (and dried, obviously) as the remaining salt will corrode the tracks and other components. 

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12 minutes ago, Neil Smith said:

You could give it a good spray all over with contact cleaner, it can't do any harm but might get to places you can't clean.

Neil

If you do, be sure to use one that leaves no residue (I think the Maplin one fits the bill). Some contact cleaners include a conductive oily substance which is intended to help the contacts to conduct. 

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Had it been clean water it might be recoverable.  My phone took a good dunking but slowly recovered 100% after opening up and giving it a quick rinse.  I think the chances of fixing are very small but worth trying.

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Depending on the circuit sometimes when a big transistor dies it takes some little transistors with it even though they don't show obvious damage, then when you replace the big one it just dies instantly. This is probably less true of modern electronics but have a look for any little transistors that might be connected to the big one.

Is this an expensive recent inverter?   if its not then just replace it.

...........Dave

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9 hours ago, Neil Smith said:

You could give it a good spray all over with contact cleaner, it can't do any harm but might get to places you can't clean.

Neil

Contact cleaner probably will not wash of the dried salts, I think you need to use di water.

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I read from time to time claims that people bung their PC motherboards in the dishwasher once in a while to clean them. They are fine if dried fully before plugging back into the PC.

I remain to be convinced though. 

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On 07/05/2017 at 09:36, Chewbacka said:

I think your transistor is made by Inpower Semiconductor (IPS) and is as marked.  

Added  -  You could have had a look on ebay as you would have found this  -  http://www.ebay.co.uk/itm/100-New-And-Original-FTP08N06A-Transistor-TO-220-/182183314075?var=&hash=item2a6af8c29b:m:mBXRlhFUZTUYHu_5XkQP91w

Added some more - There are probably some metal migration tracks which have caused the overload, so have a good look all over the board where it was wet, and give it a good brush with a stiff nail brush or similar to remove them.  Try not to remove any surface mount components whilst doing this.  If there are surface mount comps on the board, water will tend to wick underneath them so there may be shorts where you can not see, but hopefully not.  Best have a probe with your meter, but as inverters make high voltages make sure it is all disconected etc.

 

Thank you - I initially couldn't see the FT in the part number hence why my searching failed.  I have now ordered some.

I will give the board a good brush, thankfully there wasn't too much ingress so with any luck it may be salvageable.

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18 hours ago, dmr said:

Depending on the circuit sometimes when a big transistor dies it takes some little transistors with it even though they don't show obvious damage, then when you replace the big one it just dies instantly. This is probably less true of modern electronics but have a look for any little transistors that might be connected to the big one.

Is this an expensive recent inverter?   if its not then just replace it.

...........Dave

It wasn't massively expensive - £250, but I can't really afford a new one right now.  In some ways I'm pleased it was only a cheap one as I'd have cried if it were £500+ :)  It's worth having a pop if I can resolder the obvious components for £10. We'd only really used the thing in anger for about 2 weeks whilst out travelling -  most the time it sits around waiting for our next trip out.

10 hours ago, Mike the Boilerman said:

I read from time to time claims that people bung their PC motherboards in the dishwasher once in a while to clean them. They are fine if dried fully before plugging back into the PC.

I remain to be convinced though. 

Hmmmm - well she wouldn't let me have a dishwasher on the boat so I guess that's out the question for now ;)

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16 hours ago, jddevel said:

It`s a great shame that human error -something we`re all guilty of has such repercussions. I don`t suppose it`s covered under your boat insurance or if you have a house it`s accidental  damage policy?

I doubt it will be covered, and as it wasn't massively expensive we're probably better off trying to repair then taking a hit if it doesn't work.  Our house is rented out and has landlord insurance, not private contents.  Hey ho - live and learn, live and learn.

14 hours ago, Chewbacka said:

Contact cleaner probably will not wash of the dried salts, I think you need to use di water.

OK - I'll give it a go with DI water - thanks.

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