NVRAM Troubleshooting

Having issues with your NVRAM installation? We'll try to help get you going!

Below are some basic troubleshooting steps we recommend if you're experiencing a problem with an NVRAM module.

Note: We realize that everyone has a different level of experience with circuit boards, soldering equipment and repair knowledge of pinball machines. If suggestions made seem "too basic", please entertain us for a few minutes by verifying you've performed the suggested steps. This guide is meant to save EVERYONE time and hassle when things aren't working & sometimes it's the obvious stuff that actually is the cause of the problem.

RAM, Explained In Layman Terms

To understand what's happening when NVRAM or RAM doesn't work, it's easiest to think of a RAM chip like a house. A house has an address (house number, street, city, state, zip). There's people living in the house. When someone in the house orders a package, for the transaction to be completed successfully the product they ordered needs to be sent to the CORRECT address and it needs to be the CORRECT item they ordered.

In our house example, the customer wouldn't be happy getting the WRONG package at the CORRECT address. Nor would they be happy if the CORRECT package was sent to the WRONG address, because they still don't get their package.

RAM in your pinball machine works similarly. It has multiple address and data pins (really those are most of the legs on any RAM or NVRAM chip). Each one of these signals is critical for the RAM to function correctly. If just one address signal or data signal is broken or shorted to another signal, that's enough to cause the NVRAM or RAM to not function correctly. It's like sending the package to the wrong customer or wrong address -- only the pinball machine isn't getting the data it expects and weird things happen.

So how can there be a broken, intermitant or shorted signal on your board? Well, if the NVRAM required desoldering and soldering, if a trace or pad was nicked or shorted to a nearby signal, it will wreak havoc on these address and data signals.

Remember, it takes just be ONE missing signal (pin on the RAM chip) for a game not to boot.

EVERY address and data signal is important.

Problem: Machine Not Booting Or Acting Weird After NVRAM Installation

This is the most common issue since the NVRAM either works or doesn't (see "Layman" explanation above).

If the machine isn't booting at all, then something happened during the installation of the NVRAM Module, or if you had to desolder the RAM and install an IC socket then it's likely that there's a missing signal somewhere. Or in a worst case scenario, you plugged the NVRAM module in backwards (notch facing opposite direction of the notches on other chips on the board) and it blew the chip.

The best way we can help you is to isolate the problem is to prove to yourself, without a doubt, what ISN'T the issue. This will also help to alleviate some frustration, because right now everything may look like a black box & just want to get your game working again.

Try the original RAM chip in your game.

  • For plug-and-play NVRAM installations, you can utilize the original RAM chip you had removed during the installation.
  • For NVRAM installations that required soldering, if you were unable to salvage the original RAM chip you'll need to track down a working standard RAM chip that matches the model of NVRAM you've installed. So if you installed a "6264 NVRAM" in your game, you'll need a regular 6264 RAM chip.
If your game still doesn't boot or isn't functioning properly even after replacing the NVRAM with a regular RAM, then unfortunately that likely just eliminated the NVRAM module from being the problem. It's then likely a problem on the MPU board itself with a missing traces, bad solder joint, etc. Especially if the game was working fine prior to any board work that was done.

Don't Have Spare RAM? Try the NVRAM a different game.

An alternative way to troubleshoot is to try the NVRAM in a different machine to see if it appears to function correctly. You can do this if you have another game with the same type of RAM / NVRAM already in an IC socket, or a machine you already upgraded. Test the NVRAM there and see what happens. While not as 100% proof of a test as trying a different RAM in your non-working board, it can still help isolate things a bit if you don't have a spare RAM.

Okay Great, My MPU Board Has An Issue. How Do I Fix It?

Unfortunately, there may not be any "quick fix" as you'll now have to try to find what may be a needle-in-the-haystack issue. Without the tools for the job (logic probe, oscilloscope, multimeter) it will be much more difficult or nearly impossible unless you happen to visually catch an issue after looking the board over with a magnifying glass, etc.

Some basic steps in troubleshooting to isolate where the issue is are below.

STEP 1: Remove The Board From Your Game
You can't really check much in-game if the game is locking up. If you have a logic probe and know how to use it, you could try probing some of the RAM legs to check for missing signals while the game is on, but that's about it. It's now time to pull the board from your game to look at it on the bench.

STEP 2: Visually Check Solder Joints
We'd guess that 95% of the time the problem with a non-working board that WAS working before the NVRAM upgrade, is going to be at the solder joints where the IC socket was installed. An easy way to try to find an issue is to look closely with your eyes just a few inches away, or using a mangnifying glass. Inspect any traces going into pads and the solder joints themselves. Look for solder bridges. Look for nicked traces. Look for problems.

STEP 3: Check Adjacent Solder Joints With A Multimeter
Use continuity test on your multimeter to check adjacent solder joints at the back of the IC socket. On newer games there really shouldn't be continuity between adjacent most of these solder joints.

Note: On games using 5101 NVRAM, there will be continuity between some adjacent pins at the IC socket. You will need to refer to the schematic for your game to determine what SHOULD and SHOULDN'T have continuity.

STEP 4: Check Every Connection At The IC Socket
If you've exhausted the quicker methods described previously, you've done what you could to quickly isolate the issue. It's time to dig much deeper. Unfortunately this can get time consuming, but sometimes it's the only way. You're going to need to get a schematic for your game (some are available at IPDB.org, but unfortuantely there are no schematics for Gottlieb machines there.

Using the schematic, you're going to need to check each solder joint on the back of the IC socket has continuity to its end-point. In other words, if you're working with a 28-pin RAM chip, you'll need to check each one of the 28 solder joints on the solder side of the MPU board has continuity to the component (chip leg, resistor, etc) that the schematic references. You can usually eliminate some of these connections quickly if you can "see" where the trace goes on the back of the board.

Can I use a Logic Probe or Oscilloscope to troubleshoot signals?

Sure, these tools may help if you know what to look for (as far as timing diagrams, signals, etc). But we'd venture to guess that most people installing NVRAM aren't going to have this equipment and there's not really a good way for us to show anything useful in terms of what to look for.

RAM is accessed so quickly and if signals are shorted it's going to be difficult identifying what's going on with these tools unless you compare a working board's signals to a non-working board. It's also often easiest to check the more common, easier problems first, before diving into logic probes or using an oscilloscope. But, if you own the equipment, know how to use it & what to look for, then go for it!


We hear you! Believe us, we've had our share of repair attempts gone wrong over the years and it's really annoying to have to spend hours tracking down issues. It's much better if the upgrade goes successfully the first time. Unfortunately SH** happens, no matter how careful or how much experience you may have.

Our best advice if you're angry, stressed or otherwise not in a mindset patiently troubleshoot your board deeper? Walk away for a few hours, or a few days. Set the board aside. Come back to it when you're in a good mindset. Nothing good will come taking a shotgun repair approach a circuit board.

When you do decide to revisit the board, check just a few solder points at a time (as described in Step #4 above). Don't spend 3 hours poking around the board, just check a handful of solder points, walk away again and come back to it pick up where you left off. This will make it much less painful to get somewhere.

Most customers, after working through these steps, are able to identify their issue(s) and get their boards working again. So just know that the current issue you're having is only temporary.

Customer Stories (WPC Board Upgrades)

We have had multiple customers over the years email about WPC boards not functioning after an NVRAM upgrade.

Usually the email comes in like this..

"I just upgraded several WPC MPU boards with NVRAM and in each case, the machine no longer boots. I've done many successful NVRAM installations and never had a problem. I've been repairing boards for over a decade, I know what I'm doing. I have the right equipment (Hakko desoldering iron, temp controlled soldering station, etc). Solder joints look great, I don't see any issue with what I've done and I've inspected everything carefully. Help! What can I check?"

If we don't see mention that a regular RAM chip was tried in the board, that's our first recommendation. That's the "smoking gun" that proves, without a doubt, whether the NVRAM module itself is at fault or if it's an issue on the MPU board. If a regular RAM chip doesn't work, then the board has issues.

You may think "what are the chances I could upgrade 3x WPC MPU boards and none of them work?" It's happened. Thin traces and small solder pads that don't put up with a lot of heat are a recipe for issues. That's why in terms of WPC NVRAM upgrades, we rate the difficulty as "HARD". We're the only NVRAM manufacturer rating difficulty of NVRAM installations so the customer has an idea of what they're getting into, because we'd rather you know that upfront so you can make an informed decision about whether or not to attempt an upgrade yourself.

Can the NVRAM be bad?

Sure, there's always a chance. More-so if it happens to get installed wrong and the machine is turned on (since only a few seconds of the chip being shorted can blow the internal die on the nvram part).

But let's put it this way. Unless it was installed wrong, the chance of us shipping a bad chip is probably 1 in 1000. We rarely hear of issues and most of the time when we do it was from improper installation causing a blown chip.

Each NVRAM is tested multiple times before shipping (first, in a RAM tester, then via checksum test). This has worked well for making sure we ship functioning modules and the few that don't make the cut each year are weeded out (usually it's a solder problem we didn't see during assembly and we can fix it).

In other words, it's very rare that NVRAM just ships out bad.

In our experience (based on emails of issues and their resolutions), most often the problem is with the solder work that was performed on the board as part of the upgrade and not the NVRAM itself. It's just a fact of things. It's extremely rare for the NVRAM itself to be an issue unless it was damaged during installation or removal.

But, don't worry. If you do determine you have a bad module, we'll make it right for you! In most cases you'd send the module back to use (at your cost) and we'll replace or refund the cost of the module depending on your preference. Before initiating a return/exchange though, please try to use the information in this guide to determine whether this issue is with your MPU board or the NVRAM Module.

Still Having Issues?

If you're still having issues after following this guide, you can reach out to us via the Contact Page.

We'll definitely try to assist you any further if we can, but please realize we'll be limited with how we can help. That's why this guide was created, because the info listed is typically how we try to help a customer who's experienced issues with NVRAM installation.

Unfortunately there's no way to pin-point an issue directly. The best we can do is to try and isolate things from a top-down approach. It takes YOU (the customer) or someone with board repair experience to troubleshoot your board. That's why it's easiest to try a different RAM chip first, or try the NVRAM in a different game. Then, if your board still has issues even with a different RAM chip, you know that the problem exists on your MPU board. To isolate further requires a similar top-down approach to troubleshooting, but sometimes that means you eventually have to trace signals from the RAM chip to the components on the board they're connecting to using a schematic. Not an easy task, but such is the nature of electronics.

We hope this information has helped you!

If you have any additional suggestions of what to add to this page, please let us know!

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