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Aussie Pinball Forums => Technical Matters => Circuit Board Repair Guides => Topic started by: beaky on May 23, 2011, 09:25:56 PM

Title: WPC CPU acid damage repair
Post by: beaky on May 23, 2011, 09:25:56 PM
My next board repair is a WPC CPU  board with acid damage.
I will start by removing the battery holder and I.C's then i will neutralise the corrosion with a vinegar solution.
   
Title: Re: WPC CPU acid damage repair
Post by: pinnies4me on May 23, 2011, 10:07:46 PM
Gosh I hate the dreaded "acid" leaks.

Do you recommend or install for the customer remote packs?
Title: Re: WPC CPU acid damage repair
Post by: beaky on May 23, 2011, 10:12:59 PM
Gosh I hate the dreaded "acid" leaks.

Do you recommend or install for the customer remote packs?
yes i do and will be doing it for this board.  ^^^
Title: Re: WPC CPU acid damage repair
Post by: Caveoftreasures on May 24, 2011, 11:41:23 PM
I saw this board tonight, and at first glance it looks ok. THEN you look closely, and it has suffered alot of acid n heat damage.

But as I say, Never Fear, Beaky is here !  Andy will strip it n make it as physically as good as it can ever be.  ^^^

It needs alot of little parts, alot of soldering and de-soldering, but it shld come up fine. Because the parts are so many and so small, it will be a very time consuming fix, but Andy thrives on this sort of stuff.
Title: Re: WPC CPU acid damage repair
Post by: beaky on May 26, 2011, 04:24:07 PM
I have removed all the components pretty much the same way Strangeways did in his thread on acid damage repair http://aussiepinball.com/index.php?topic=2343.0 (http://aussiepinball.com/index.php?topic=2343.0)

There are a few tracks that have been eaten away and the acid had made its way down to the plugs at the bottom of the board.
A lot of the legs on the components were corroded nearly all the way through and there was a big blob of corrosive crap under one of the I.C.s so of course i will be replacing all these with new parts.
I will add a parts list later on for this
Title: Re: WPC CPU acid damage repair
Post by: beaky on May 29, 2011, 05:08:56 PM
after removing all the solder i sanded all the corroded areas with fine sand paper to reveal the copper, i then cleaned with the 50/50 vinegar solution to neutralise any remaining acid. I then rinsed in warm water and cleaned with alcohol. I then tinned all the tracks & pads then de soldered all the solder from all the holes. cleaned with alcohol again and gave the top of the board a light coat of pcb lacquer (the type that is able to be soldered through) before i lacquered the board i masked all the plugs and empty I.C. sockets with masking tape as i do not want any lacquer on these as it will cause all types of trouble if theses are sealed        
Title: Re: WPC CPU acid damage repair
Post by: beaky on May 29, 2011, 05:19:45 PM
next i have added all the I.C. sockets and resistors making sure the solder flows through the holes to the top side. fortunately all the solder throughs where ok.
I have found that a lot of the tracks have corroded right through where the tracks meet the pads. the corrosion is so small you need a strong magnifying glass to see them.
now to wait for the axil type capacitors to turn up so i can finish the job.   
Title: Re: WPC CPU acid damage repair
Post by: beaky on June 28, 2011, 07:15:13 PM
I have now finished this repair.
I added the jumpers for all the corroded tracks on the bottom of the board.
all switch rows, columns and dedicated switches are working fine.
I finished up with another coat of clear lacquer top and bottom then added some labels for the headers and a remote battery holder.  
Title: Re: WPC CPU acid damage repair
Post by: ajlaird on June 28, 2011, 09:20:18 PM
Nice one, a fair bit of work involved to fix that board!
Title: Re: WPC CPU acid damage repair
Post by: beaky on June 28, 2011, 09:27:51 PM
thanks mate.
another board is saved from the scrap heap.
Title: Re: WPC CPU acid damage repair
Post by: zoltar420 on November 04, 2011, 05:05:59 AM
Wonderful thread and great results on your work.  I am new to the boards and am currently trying to fix my T2 pinball.  I saw you added jumpers for the messed up tracks.  How can you tell if a track is messed up?  Sorry for the noob questions, im new to board repair and would really love to get my T2 acid leak fixed.  Any links or pointers to get me in the right direction is appreciated.

Thanks Zoltar!!  <..>
Title: Re: WPC CPU acid damage repair
Post by: Caveoftreasures on November 04, 2011, 05:26:06 AM
Easiest way, SEND YOURS TO ANDREW (BEAKY) and get it fixed properly for a small amount. Andy does all my board repairs, as well as alot of other peoples. Send him a PM (personal message) by cicking on his photo/name etc.

He usually buzzes out all the tracks with a multi meter, plus other various tricks of the trade, as well as very close inspection with magnified lenses etc.

Well worth it to get it fixed by someone with over 20 yrs of experience. Hope it helps.  ^^^
Title: Re: WPC CPU acid damage repair
Post by: MartyJ on November 04, 2011, 07:39:01 AM
Easiest way, SEND YOURS TO ANDREW (BEAKY) and get it fixed properly for a small amount. Andy does all my board repairs, as well as alot of other peoples. Send him a PM (personal message) by cicking on his photo/name etc.

He usually buzzes out all the tracks with a multi meter, plus other various tricks of the trade, as well as very close inspection with magnified lenses etc.

Well worth it to get it fixed by someone with over 20 yrs of experience. Hope it helps.  ^^^
Wonderful thread and great results on your work.  I am new to the boards and am currently trying to fix my T2 pinball.  I saw you added jumpers for the messed up tracks.  How can you tell if a track is messed up?  Sorry for the noob questions, im new to board repair and would really love to get my T2 acid leak fixed.  Any links or pointers to get me in the right direction is appreciated.

Thanks Zoltar!!  <..>

Easiest way to test tracks is to have a good quality digital multimeter, set it to 'buzz' which is a continuity setting. Put one probe on the start of the track and the other probe on the end of the track. You will get a nice buzz noise from multimeter to let you know. Visual inspection is also a must.

Feel free to post ANY questions in the tech help threads and you will get answers..
Title: Re: WPC CPU acid damage repair
Post by: zoltar420 on November 04, 2011, 11:41:37 AM
Thanks for the quick replies!  I will try out the multimeter, see what I find.

Thanks Zoltar  ()
Title: Re: WPC CPU acid damage repair
Post by: beaky on November 04, 2011, 08:44:39 PM
Wonderful thread and great results on your work.  I am new to the boards and am currently trying to fix my T2 pinball.  I saw you added jumpers for the messed up tracks.  How can you tell if a track is messed up?  Sorry for the noob questions, im new to board repair and would really love to get my T2 acid leak fixed.  Any links or pointers to get me in the right direction is appreciated.

Thanks Zoltar!!  <..>
make sure you neutralise the corrosion. if there is corrosion damage around or on any of the i.c. pins the I.C. will have to be removed to clean up any corrosion under it.
Title: Re: WPC CPU acid damage repair
Post by: johnwartjr on November 18, 2011, 04:58:42 AM
Very nice job, I must find some of the PCB paint you reference earlier on, I've been tinning my tracks when I do similar jobs, but if I had the ability to make them appear 'green' again, it would add a nice touch to the repair!
Title: Re: WPC CPU acid damage repair
Post by: beaky on January 09, 2012, 09:56:44 PM
I use a normal clear P.C.B solder through clear lacquer and then go over some of the tinned tracks with a permanent green marker, I then give it another coat of lacquer.
I haven't found a perfect match marker yet but i will keep trying to find one, when I do I will let you know what brand and colour. 
Title: Re: WPC CPU acid damage repair
Post by: bigdaddy on January 09, 2012, 10:03:24 PM
 :D NOICE  #*#