Ref this post: https://pinside.com/pinball/forum/topic/volume-suddenly-at-maximum-wpc-hurricane#post-6866321

It looked like rlbohon3 was able to source the U5 (X9C503) IC in ref. post. I'm working on a game that may need U5 (X9C503) replaced. I'm having trouble finding that IC, but there is a Maxim IC that is available and looks like it may be a compatible replacement (DS1804-050). Does anyone know if the Maxim chip will work as a substitute for the X9C503?

I should have asked this...The problem the customer is having, is as follows:

The game is set to (made up numbers here) volume 10. The volume stays at the set volume the entire time the game is ON. After coming back the next day or whenever, the volume is at 7 (or some other setting). So I was thinking it might be bad memory in the U5 chip.

I looked at Marco and didn't find that, but I didn't think to search on the old part number. Thank you.

If you look at the datasheet, the X9503 has on-chip nv-ram that is used to save the setting. I assumed that's what was used, but I don't really know.

EDIT...
Here's a paragraph from the datasheet:

When the device is powered-down, the last wiper posi-
tion stored will be maintained in the nonvolatile mem-
ory. When power is restored, the contents of the
memory are recalled and the wiper is set to the value
last stored.

There are not a lot of posts about that IC and nothing about the volume changing between power ups. It is the only thing I can think of to try to solve the issue.

I don't think it actually shows a number (WPC owners chime in here). I think it just shows a bar graph level. I was just using the number thing, to describe what was happening.

OK it looks like the volume does have a number -- I found a video on youtube.

If it is not U5 causing the problem, I'm not sure where to go next. Coyote comment makes sense -- there is no obvious way to read the current setting on U5, unless the CPU somehow measures the current volume resistance and puts a number on it when the game starts.

Let me know if anyone has suggestions on how to troubleshoot the problem further.

Thank you.

Robotworkshop Good idea, but this is a friend's game and neither of us have any other WPC games.

PinRetail He said he recently changed the batteries and there are no other issues of lost game settings or errors displayed. But its a great idea and I'll make sure the voltage is >3.5V at D2, and double-check there are no startup errors, and verify one 'bong' at power on. I'll report back with the results.

I appreciate the suggestions...keep the ideas coming

This is a really good idea, which I should do even if it does not solve this problem. I've changed all my games to the RAMTRON (I wish they still made the PDIP version!) and never had a problem.