Hello guys,

I would need your help today cause I'm trying to fix a volume issue on my CV.
The pin was working properly till yesterday ... then suddently, volume setting went up till max (32) without any reason.

First, I decided to unplug the speakers before loosing my ears

Then, I have checked the coindoor buttons : all were unresponsive. Everything else is working on the pin.
After that, I have checked the buttons one by one with my DMM : got 12V on each, then 0V when pressed.

I have double checked J205 and nothing bad there.

After, I have removed J205 wire and also the batteries to force a factory reset.
Right after the factory reset and the RingMaster test, the volume goes up to max from 12 to 31 in a few seconds (j205 unplugged here)
The screen keeps showing the volume level at max forever...

What can I do now to troubleshoot this issue ??

Thanks at all for your help

Yes sure, I will do that tomorrow. it’s too late now here in Paris

What was you thinking about ?

batteries were old (max date 2014 on them) but I did not mention any leakage or corrosion.

According the fact j205 has been removed and the dot is always showing the volume message at max, can we conclude the issue is coming from the MPU?

Yes, you’re right.. the batteries are quite far from the switch matrix.

I don’t think there is something related to leakage there, but I am gonna check this carefuly tomorrow.

After, I am gonna check U16 with my logic probe tester.

Some pictures ...

7ACB0339-DC7B-4FEA-AFAA-9B7C01112019 (resized).jpeg

7BB3CC6F-A0DA-4C6A-8F4E-3F0E1F924E6D (resized).jpeg

Ok i'm gonna check this in a few minutes.

What I have done just before your message was testing the U16 pins according to the guide i have found here :

http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Direct_Switch_Problems

But I'm not sure if I'm doing this well with my DMM...
Below is what I have done :

I have put the RED wire to U16 - pins 5 and then the black wire to ground braid.
Then pins 7 , 9 , 11

J205 is connected, no buttons pressed of course.

each pin is showing 12V DC when the red wire is on the pin and the black on the ground braid.
When i remove the black wire, the DMM shows 0VDC

I'm not sure if my test is useful or not ...

U16 pin 1,2,13,14 = 5.13V DC

Wow, ok.
I'm gonna remove the PCB right now and check that + pictures .
I'll keep you posted in a few minutes.

Fixed by pressing U9 !! and all the others UX on the MPU board

Thanks at all for your help !

Yes I’m gonna study the nvram way.
Never installed on my pinball machines so far.
I’m using mostly industrial batteries ( no leakage guarantee)