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Author Topic: P94. Salvageable ?  (Read 1616 times)

Bob K

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P94. Salvageable ?
« on: June 03, 2016, 04:43:21 PM »

I am hoping Dave M can answer this one.

I love the Action P94, and have them in all my multi shaft boats.  Auto setup, ultra reliable, does everything it says on the tin. 

However, I have one that has suffered two sinkings (you can guess which ship) and amazingly still works.
A bit of surface corrosion, mainly on the pcb tracks, but the pot "R1" is getting a bit iffy.
I have replaced it with a new P94 unit that I had as a spare.

What I would like to know is if it is practical to refurbish the old one, basically a better clean than I can do plus replacing the R1 pot.  Is it a practical proposition, even an economic one? 





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plastic

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Re: P94. Salvageable ?
« Reply #1 on: June 03, 2016, 05:54:51 PM »

As far as I can see, all of the parts on that board should be happy being submerged & dried out - the pot & switch may suffer slightly so I'd replace the pot, but everything else should be ok.
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inertia

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Re: P94. Salvageable ?
« Reply #2 on: June 03, 2016, 06:33:27 PM »

Bob

Then only real problem might be soldering a new component to the corroded copper track. Sometimes you get lucky; sometimes you don't. Get yourself a glassfibre pencil http://www.maplin.co.uk/p/abrasive-fibreglass-pencil-kr61r and clean off all the surface crud as much as you can. Do check Flea-Bay first - Maplin are not known to be cheapest for anything. If you have any desolder braid then use that to remove the solder from the contacts of R1. If you PM me your address then I can send you some braid and a new pot for a mere few thousand pounds + P&P + VAT.*  8)

The fleet must be kept afloat at all costs!

Dave M

*This is for the benefit of those who still view me as a rampant capitalist. In reality the usual fee is a donation of your choice to the RNLI (Minimum 1).
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malcolmfrary

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Re: P94. Salvageable ?
« Reply #3 on: June 03, 2016, 10:13:10 PM »

Corroded solder can be a barsteward to melt - it needs a really good surface clean and a very hot iron with liquid solder on the tip to ensure that the heat goes where it is needed quickly.  A potential problem with a circuit that has been submerged is that the corrosion will not be just oxides, but other mineral salt products caused by the electrolytic action.
But a good clean to get rid of the surface muck and for the pot, giving it a good bath in alcohol switch cleaner and a good waggle while wet might restore its function without the hassle of digging it out and replacing it.  Braid is good for removing solder, I prefer my solder sucker.  Its just so satisfying to use.
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inertia

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Re: P94. Salvageable ?
« Reply #4 on: June 03, 2016, 11:21:26 PM »

Braid is good for removing solder, I prefer my solder sucker.  Its just so satisfying to use.
I always did harbour some suspicions about you, Doc...
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wombat

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Re: P94. Salvageable ?
« Reply #5 on: June 04, 2016, 10:36:39 PM »

Before trying any desoldering take either a brass bristle brush or some wire-wool to the board to get the solder shiny before desoldering. Looking at the pictures replace the pot and the resistor next to it. I would also pop out the IC and reseat it a few times to ensure good contact.


Wom
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