(Topic ID: 197541)

Whitewater Bigfoot acting up.


By Arcade

2 years ago



Topic Stats

  • 9 posts
  • 3 Pinsiders participating
  • Latest reply 2 years ago by Arcade
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There have been 4 images uploaded to this topic. (View topic image gallery).

Bigfoot board (resized).jpg
WH20 (resized).png
IMG_4548 (resized).JPG
IMG_4547 (resized).JPG

#1 2 years ago

Hey all.
Suddenly the spinning head on my Bigfoot started going bonkers.
Yesterday I turned on the game and the head was in a constant fast spin counter clockwise and would not stop until power off.
Then today he just refused to turn during a game at all, but he did reset himself at power up.
I first suspected the opto board but after taking it off and cleaning it well he still will not work during a game.
However he passes all test in test mode. Both optos register well, and the game knows his position.
He also spins fast counter clockwise in test mode but very slowly clockwise.

I have read about the C2 cap leaking on the little driver board under the playfield on the bottom left.
I did not have time to remove this board yet and check it but I did snap quick pic with my phone.
I can't see any damage to U1 from the photo, but thought I would post it up in case some of you have better eyes for this stuff.
What would you guys try first?
Photo of driver board and the opto board I cleaned up below.

IMG_4547 (resized).JPG

IMG_4548 (resized).JPG

#2 2 years ago

Well, I was just going to pull off C2 since they seem to be a problem for many people with leaks underneath.
I thought I had a 35v cap to replace it with but all I have are 25v.
So now I have to wait until Monday when my local store opens again.
While I have the board off I am going to check all the traces to U1.

#3 2 years ago
Quoted from Arcade:

Well, I was just going to pull off C2 since they seem to be a problem for many people with leaks underneath.

Looks like you are on the right track. Unfortunately, there definitely was some electrolyte leakage from C2 and it is corrosive just like when alkaline batteries leak. So zooming up, I see U1, D6, C2, and R1 that need to be replaced, at the very least. It is best to inspect the board with 4x or higher magnification.

Once you remove these parts, it is best to lightly sand down the traces affected clean with vinegar and clean after with alcohol before installing new parts. Pretty much the same process as if you were cleaning up battery corrosion. From my experience, it is best to apply the heat only to the bottom side of the board when you are desoldering parts. Though, I tend to cut the legs/part on the topside to make it easier to remove. When you apply heat directly to the corroded area without treating it, it just eats away the traces/pads very quickly.

You can compare the dull color of the solder of what I had circled to other parts of the board that have shiny solder. That is what you're looking for in this case. Also to the left of the C2, there is a trace that was affected, which turned green just like U1 pin 1.

WH20 (resized).png

#4 2 years ago
Quoted from PinballManiac40:

Looks like you are on the right track. Unfortunately, there definitely was some electrolyte leakage from C2 and it is corrosive just like when alkaline batteries leak. So zooming up, I see U1, D6, C2, and R1 that need to be replaced, at the very least. It is best to inspect the board with 4x or higher magnification.
Once you remove these parts, it is best to lightly sand down the traces affected clean with vinegar and clean after with alcohol before installing new parts. Pretty much the same process as if you were cleaning up battery corrosion. From my experience, it is best to apply the heat only to the bottom side of the board when you are desoldering parts. Though, I tend to cut the legs/part on the topside to make it easier to remove. When you apply heat directly to the corroded area without treating it, it just eats away the traces/pads very quickly.
You can compare the dull color of the solder of what I had circled to other parts of the board that have shiny solder. That is what you're looking for in this case. Also to the left of the C2, there is a trace that was affected, which turned green just like U1 pin 1.

Thanks.
I will go ahead and take out the board and pull the cap off to start the cleaning process while I wait for my parts store to open.

#5 2 years ago
Quoted from Arcade:

Well, I was just going to pull off C2 since they seem to be a problem for many people with leaks underneath.
I thought I had a 35v cap to replace it with but all I have are 25v.
So now I have to wait until Monday when my local store opens again.
While I have the board off I am going to check all the traces to U1.

What's the voltage being applied to that cap? I ask because a 25V capacitor is actually better than a 35V if it's only got 12 volts going to it.

#6 2 years ago
Quoted from bobukcat:

What's the voltage being applied to that cap? I ask because a 25V capacitor is actually better than a 35V if it's only got 12 volts going to it.

Here is a photo I pulled from a similar thread to mine below.

Link to other thread.
https://pinside.com/pinball/forum/topic/another-bigfoot-problem-wh20

Looks like it is 12 volts only.
Any experts out there. Because I have a ton of 25v 100uf caps in stock.

Bigfoot board (resized).jpg

#7 2 years ago

25 Volt cap will work perfectly fine, electrolytic capacitors go bad faster if they are over-rated for the circuit they are used in. WMS probably used 35V because they were cheaper or were already used elsewhere in the BOM.

#8 2 years ago
Quoted from bobukcat:

25 Volt cap will work perfectly fine, electrolytic capacitors go bad faster if they are over-rated for the circuit they are used in. WMS probably used 35V because they were cheaper or were already used elsewhere in the BOM.

Awesome. Thanks.

#9 2 years ago

Success.
Big foot now working 100%
I removed the cap. It had leaked a bit on the negative leg.
Took the short route and just cleaned all the other parts and traces with vinegar then alcohol.
Tested all connections with a meter and then reinstalled.
He is working great again.
Thanks everyone.

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