(Topic ID: 242965)

Why Doesn't Navram save date and time?


By Ericpinballfan

5 months ago



Topic Stats

  • 37 posts
  • 17 Pinsiders participating
  • Latest reply 5 months ago by schudel5
  • Topic is favorited by 2 Pinsiders

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#1 5 months ago

With Navram installed why is it everytime I turn pin on its July 1st at 4pm?
I know i could shut off clock as not visible, but its an experiment.
Just really wondering why navram won't save date and time?

#2 5 months ago

It’s because the real time clock is no longer being driven by batteries when the game is off

#3 5 months ago
Quoted from Wharhed:

It’s because the real time clock is no longer being driven by batteries when the game is off

Thank you. Won't lie. I kinda already knew this.
Back to my topic question.
We know the why because of no batteries. But, we have the technology to ad memory backup,
Why no battery on Navram?

#4 5 months ago
Quoted from Ericpinballfan:

Thank you. Won't lie. I kinda already knew this.
Back to my topic question.
We know the why because of no batteries. But, we have the technology to ad memory backup,
Why no battery on Navram?

If your gonna use a battery then why nvram at all. That doesnt make any sense.

#5 5 months ago

NVRAM doesn't need batteries, that's why

Batteries wouldn't change how it behaves, it's stores data persistently without the need for power.

It's easier to think of it as equivalent to a flash drive that's plugged into your PC. You can put that in your pocket and the data is still on there, but that data never changes unless you manually change it (so a clock would never keep time).

#6 5 months ago

I'm confused at what you're getting at, the clock time is being saved. It just only runs when the game is on instead of running off battery power and game power.

Some people run both (which kind of defeats the purpose of using nvram) to keep midnight madness working.

If I'm not mistaken stern used internal battery ram on some of the white star games.

#7 5 months ago
Quoted from Mitch:

If your gonna use a battery then why nvram at all. That doesnt make any sense.

What about an nvram with a slot for a coin cell battery so that we can have a rtc. wouldn't have to use it but if you did then you get rtc.

#8 5 months ago
Quoted from Syco54645:

What about an nvram with a slot for a coin cell battery so that we can have a rtc. wouldn't have to use it but if you did then you get rtc.

Kinda of what I was thinking.

Quoted from Slim64:

Some people run both (which kind of defeats the purpose of using nvram) to keep midnight madness working.

Quoted from Mitch:

If your gonna use a battery then why nvram at all. That doesnt make any sense.

That's just the issue.
I want the games to have the Navram, eliminate the 3 AA batteries, and have the machine keep proper time.

#9 5 months ago
Quoted from Syco54645:

What about an nvram with a slot for a coin cell battery so that we can have a rtc. wouldn't have to use it but if you did then you get rtc.

acebathound See this idea above

#10 5 months ago

If you look at the schematic of TAF (which you reference) the Vbatt from the batteries goes to the RAM chip, ASIC and a bunch of other stuff which some controls and keeps track of time. Obviously when you remove the batteries that voltage goes away. The NVRAM can't push any voltage out to keep those running when the game is off. You'd have to go back to batteries to do that.

Now I'm not familiar with the pin-outs for the NVRAM but the Vbatt pins may not be connected to anything internally so running batteries and a NVRAM may be fine. But there are some jumpers on the Vbatt line that can be removed to isolate the RAM chip from battery voltage.

You'd basically have to find a NVRAM chip with voltage output to drive all the other stuff. I don't think that exists. And if it did you'd have to recharge the batteries and now you're into leakage issues again. You could make a plug-in power supply and connect to the Vbatt terminals, but if the power goes out or you unplug the game you'll lose the time. I'd suggest understanding the schematic and NVRAM before you start running 2 sources.

#11 5 months ago
Quoted from Ericpinballfan:

Kinda of what I was thinking.

That's just the issue.
I want the games to have the Navram, eliminate the 3 AA batteries, and have the machine keep proper time.

Why not just do a remote battery holder and keep the factory ram in place. I thought the only advantage over factory ram with nvram was the fact that it retains memory without power?

#12 5 months ago
Quoted from Slim64:

Why not just do a remote battery holder and keep the factory ram in place. I thought the only advantage over factory ram with nvram was the fact that it retains memory without power?

Essentially NVRAM is a fit and forget thing, you never have to think about replacing batteries again.

That said I don't know how long Lithium batteries typically last in a pinball machine, I'd assume they would hold a charge for at least 2 if not 3 years.

How much is NVRAM and how much would it cost you to get it fitted (if you aren't capable yourself)? I assume that price would buy an awful lot of packs of Lithium batteries...

If money is no object then outside games that use the RTC it's a no-brainer.

#13 5 months ago
Quoted from Durzel:

That said I don't know how long Lithium batteries typically last in a pinball machine, I'd assume they would hold a charge for at least 2 if not 3 years.

I run Energizer Lithium AA batteries in all my games. I just did this to all of them a few years ago (2016 perhaps). I have spot checked some by pulling them out with the game on and testing voltage. The ones I've pulled were well over 1.6V each. I did have one game with something bad on the board that was killing even the Lithium Energizers. I thought it was the blocking diodes and I replaced those and still the same issue. I did end up putting NVRAM in that one game and all is fine now, but obviously no clock.

#14 5 months ago
Quoted from schudel5:

I run Energizer Lithium AA batteries in all my games. I just did this to all of them a few years ago (2016 perhaps). I have spot checked some by pulling them out with the game on and testing voltage. The ones I've pulled were well over 1.6V each. I did have one game with something bad on the board that was killing even the Lithium Energizers. I thought it was the blocking diodes and I replaced those and still the same issue. I did end up putting NVRAM in that one game and all is fine now, but obviously no clock.

Out of curiosity, did you use remote battery holders?

#15 5 months ago
Quoted from Ericpinballfan:

Out of curiosity, did you use remote battery holders?

Nope. Just replaced alkaline with lithium.

#16 5 months ago

Lot of effort to run a wildly inaccurate clock.

Don C.

#17 5 months ago
Quoted from Syco54645:

What about an nvram with a slot for a coin cell battery so that we can have a rtc. wouldn't have to use it but if you did then you get rtc.

There is literally no difference (except for power capacity) between a lithium coin cell battery and AA lithium batteries you can just install in your CPU battery pack. If this is what you are wanting, don't bother converting to NVRAM.

Quoted from Ericpinballfan:

That's just the issue.
I want the games to have the Navram, eliminate the 3 AA batteries, and have the machine keep proper time.

What you are asking is not possible as the RTC resides on the ASIC.

#18 5 months ago
Quoted from Durzel:

That said I don't know how long Lithium batteries typically last in a pinball machine, I'd assume they would hold a charge for at least 2 if not 3 years.

AA Lithium batteies should last 5-10 years depending on the climate the machine is in.

#19 5 months ago
Quoted from Ericpinballfan:

Out of curiosity, did you use remote battery holders?

If you go with lithium batteries, there is no reason to even bother with a remote holder; in the extremely rare event these do leak, you will never see the kind of corrosion you get with alkaline batteries.

#20 5 months ago
Quoted from Don_C:

Lot of effort to run a wildly inaccurate clock.

again, replacing alkaline batteries with lithium batteries is zero effort.

#21 5 months ago
Quoted from Pin_Guy:

again, replacing alkaline batteries with lithium batteries is zero effort.

It's also zero effort for someone to grab alkaline batteries to replace them with later.

#22 5 months ago
Quoted from ForceFlow:

It's also zero effort for someone to grab alkaline batteries to replace them with later.

I guess...just didn't occur to me as no one but myself has ever worked on any of my machines.

#23 5 months ago

To keep the same functionality, just get a battery holder that can mount somewhere outside of the backbox and still be wired there. They are easy to find and cheap.

#24 5 months ago

RTC is cool to have in some games, depending on if you care about those features.... most don't.

#25 5 months ago

The ASIC has the RTC built into it. You need to power the ASIC to get the RTC to run when the game is turned off. The ASIC consumes too much current for a lithium coin cell. CR2032 would last a year or so before it dies based on some standby current readings german pinball posted.

The best idea I came up with, and people still said it was a dumb, was to use NVRAM and a 5v wall wart to power the ASIC when the game is off.

https://pinside.com/pinball/forum/topic/wpc-real-time-clock-and-nvram-solution

Worked fine. I had Johnny Mnemonic setup like that ^

#26 5 months ago
Quoted from Pin_Guy:

I guess...just didn't occur to me as no one but myself has ever worked on any of my machines.

At some point you will sell a few of your games.

#27 5 months ago
Quoted from ForceFlow:

It's also zero effort for someone to grab alkaline batteries to replace them with later.

Which is why I tell people to put on a "replace only with lithium batteries" label on the board.

#28 5 months ago
Quoted from schudel5:

I did have one game with something bad on the board that was killing even the Lithium Energizers.

Did that game have a WPC Rottendog MPU? I have seen 2 already eat up Lithium batteries within 8 months. Even alkalines seem to get taken out in a month.

#29 5 months ago
Quoted from PinballManiac40:

At some point you will sell a few of your games.

Perhaps when I'm no longer part of this world.

At that point everything will probably go together including all my PCB repair gear, spare boards, spare parts, etc...

#30 5 months ago
Quoted from PinballManiac40:

Did that game have a WPC Rottendog MPU? I have seen 2 already eat up Lithium batteries within 8 months. Even alkalines seem to get taken out in a month.

Nope. Original WPC95. It was weird that only one of the cells went dead, the other two were fine. Defies logic if you ask me.

#31 5 months ago
Quoted from schudel5:

Nope. Original WPC95. It was weird that only one of the cells went dead, the other two were fine. Defies logic if you ask me.

Did you check to see if that Lithium set was made in China?

#32 5 months ago
Quoted from PinballManiac40:

Did you check to see if that Lithium set was made in China?

No. With 32 other games all running Lithiums and just this one taking out a single cell, whether lithium or alkaline, I didn't think that would matter. All batteries were bought at the same time from the same vendor in the same bulk pack. I've not had a single issue with any other cell in any other game.

#33 5 months ago

Energizer Lithiums coupled with a 3 dollar remote battery holder and your troubles are over.

#34 5 months ago
Quoted from schudel5:

I did have one game with something bad on the board that was killing even the Lithium Energizers. I thought it was the blocking diodes and I replaced those and still the same issue.

Could this issue (http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#WPC-95_CPU_Factory_Modification) be the reason?

#35 5 months ago

Hmmm. I'll have to check and see. Although it's not either game it could be the issue. Thanks for the link.

#36 5 months ago
Quoted from schudel5:

Hmmm. I'll have to check and see. Although it's not either game it could be the issue. Thanks for the link.

I don't know the history of your machines but people / operators frequently swapped boards between machines. I never assume that a board in someone's machine is an original (although in most cases it is an original and matched serial numbers).

#37 5 months ago
Quoted from DumbAss:

I don't know the history of your machines but people / operators frequently swapped boards between machines. I never assume that a board in someone's machine is an original (although in most cases it is an original and matched serial numbers).

Prototype machine serial 00001. So I have no idea if it was grabbed from another machine when they were building it or what. There are no serial numbers on the boards, just the cabinet. Anyways, NVRAM installed and problem is gone... so far.

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