1983 IGT / ARISTOCRAT Battery replacement?

[Jeff/fixable?]

Sorry, let's try this again, I don't know what happened to my first post.  Do these old machines have a trickle charger? What lithium ion battery to use based on photos? This machine has not been plugged in for over 15 years. Thank you any help will be very much appreciated.

[rickhunter]

Those are not lithium ion batteries, they are just plain old nicads.  Since they are already leaking, you should remove them immediately to prevent any further damage to the pc board.  The more modern S2000 slot's mpu's are known get damaged by leading batteries.

[Jeff/fixable?]

Thank you. Do you or anyone know if it's ok to replace those old batteries with lithium? If so which one/ones? The batteries look like they had two connections on one side of the board, and one connection going to the board on the other side, anyone understand that? On the two connection side, it looks like the acid corroded one of the connections, is that possible? Thank you. 

[rickhunter]

You can't just switch battery chemistry on batteries that have a charging circuit. Lithium ion batteries can cause fires if they don't have a smart charging circuit that stops the charge when they reach capacity.  I would remove the battery assembly and cut open the plastic sleeve to see the batteries that are inside.  Most likely, they are just plain old 1.25 v nicads.  you could just buy a pair with solder tabs and connect them to the mainboard.  And yes, looks like the acid leak corroded the connection to the board.  Your machine may require further evaluation if the acid damage is more extensive than just the battery leads.

[Jeff/fixable?]

Great job explaining, thank you! Do you or anyone know if I can use these NIMH instead of the NICAD?


Nickel-metal hydride (NIMH) batteries have a higher capacity than nickel-cadmium (NICAD) batteries, which means that they can generally power your device for longer. They also don't suffer from the same memory effect, so they won't “forget” the ability to achieve a full charge over time.[/color][/size]Mar 9, 2017[/size][/size]Thank you again.

[rickhunter]

The charging profile of a standard NiCd battery would overcharge a NiMh battery causing the battery to overheat.  NiMh batteries do not do well when overcharged and could potentially lead to other issues.  The rule of thumb is, you can charge NiCd batteries with a NiMH charger, but not the other way around.

[Jeff/fixable?]

Thank you again! I replied before but it didn't go through.

[gwslotting]

What a coincident? I just acquired a non working unit exactly the same, a few weeks ago. Except mine is a nickle unit. 


Can we share information to help each other, at NLG forum or private message.


My first concern is also my batteries, in worse shape than yours.


1. In many designs, replacing the board batteries requires tedious RAM clear or equivalent procedure and backup chips. Can someone tell by the design of these old boards in such is necessary. I am still waiting for a reply to find a manual and schematic.


2. Does soldering in parallel new batteries before removing the old leaking ones increase the chance of not having to do RAM clear/reset


3. Are these just 1.5 volt ni cads


4. My unit was last fired up 12 months ago and the seller said that was the last time it worked.  So RAM / EPROM data still there?

[Jeff/fixable?]

Hello, no one has mentioned anything to me about the RAM etc? I did read that possibly with these older machines that's not a concern/issue? The batteries are 1.2 volt nicad each. I've been told by several people only to use the nicad batteries. There are several places that you can order "flat top" with tabs already soldered on. That's my next move, unless you have more information.
My board checks out so far where there was some acid damage, just not sure if the green material that is lifted off the board a bit in a couple of places is a problem? How do you fix the green part? Thank you to everyone here for all the help so far.

[gwslotting]

Hi.


Disconnecting the battery may affect RAM /EPROM data on newer machines such as IGT 2000 etc. I agree with you that maybe these old machines, RAM/EPROM  data mah not affected due to the older main CPU processor used. But since I am still studying which processor and those  chip sets with white labesls that are  used on this board and their role, I am still weighing between removing the batteries now messing up data,  versus risking more damage to the circuit board. Right now the damage/corrosion only limited to the connections at the batteries terminal. Thank God. I am still thinking about adding a new set up batteries in paralle to the old ones just to give it juice.


My approach to replaceing batteries is not to use place the new batteries on the board, but solder jumper leads that extend to the outside of the Metal PC board enclosure, add a double AA battery holder, with modifications if necessary to avoid future hassel if the batteries have issues. See photo


By the way, do you have any manuals, printouts  on this machine.  I have nothing.


What do you mean by "My board checked out so far?"  Did you just turn on the machine?


Finally, "what to you mean by fixing the green thing".  I must have missed that part of your post somehow.

[Jeff/fixable?]

Hello, Great idea on the battery replacement! Sorry I do not have any manuals. I did a continuity test on the areas that looked corroded, everything checked out fine. On the green stuff, I was referring to the silk screen part of the circuit board that is corroded. Please let me know what you figure out on the chips/ram etc, because it's too late for me I removed the batteries. Thank you again. 👍

[Paul]

To clean off the battery corrosion I clean the corroded area with vinegar.
The battery corrosion is from the alkaline in the battery  and the vinegar is a weak acid.
That will stop any further damage.
Just rinse and dry the board very well before reusing.
Here in Texas I just put them in the sun for a couple of hours.

[Jeff/fixable?]

Great, thank you 👍. I did a bit of cleaning with alcohol and a q-tip, I hope that's okay? I read that online somewhere.

[gwslotting]

I would go with Paul's recommendation and then alcohol.  Alcohol does not neutralize/dissolve the old battery leak as well. Alcohol best use in driving away remaining moisture on circuit boards. Some even dip cell phones into alcohol after the cell phone got wet or drops into water, and it works. Google something like "how to clean battery leak on circuit boards" and one will find tons of vidoes and articles

[Paul]

When I repair boards with acid damage ( battery leakage or capacitor leakage)
I’ll remove leaking components then put the board into a tray of vinegar till all the foaming stops.
Then rinse in a tray of distilled water to remove the vinegar.
Then if the board is small enough I put it in a tray of 95% or higher alcohol.
If to big, I use compressed air to remove most of the water then dry in a oven or outside in the sun.
Just remove EPROMs from the board to protect from UV light.

[gwslotting]

Thanks for sharing Paul..
[
Only thing is nowadays  91% isoprophy alcohol mostly sold in stores. Someone put them on ebay at $40 (incl shipping) per 32 ml, ie. $160 per gal !!!  Label said "anti bacterial, anit viral.. 91% alcohol. Back label said only active ingredient is 91% isopropyl and water"  I bet the 91% is fake too, maybe only 50%.. Unless I am way off, normal times 32 fl oz is less about $1.50 per bottle at Walmart or CVS (are we allow to mention store names?)

Disgusting during COVID.  I guess freedom means not wearing face mask, infect others and price gouging. I am in California. Both Texas and California are in deep.....on COVID issues


https://www.ebay.com/itm/91-Isopropyl-Alcohol-32-oz-Anti-Virus-Antibacterial-Cleaner/333663974800?hash=item4dafec3590:g:Kq0AAOSwHiVfF79B

I hope more Ebay users report this seller under  "Report this item  price gouging".

99% isopropl by mail order price went up crazy. Only 50% iso  left in stores, won't even kill the virus ! I guess your approach leaving the board under shade in the hot Texas sun is cheaper. Yes, covering up those EPROMS.

Question: many of these 40 year old electronic boards with 40 year old RAMS and EPROMs are very rare. Would you take the risk of pulling them and copy them on EPROM programmers, make of few back ups, or at least read the binary file to see if there are any corrupted codes?


take care

[Paul]

If you can’t find anyone that has already copied the chip files the it would be a
good idea to pull the chips and copy them.
I’d buy new chips to copy the files to and put the original chips away for safe keeping.
BUT - Just remember to be very careful as if you break the chip the machine may
 never work again.

91% will work it just has more water in it.
Try your local grocery or drug store.

[jrr]

Not being familiar with IGT slots I do have a question - why are you not replacing the CMOS RAM with NVRAMs? In the video/pinball side of things we are happily using NVRAM to replace 5101s, 6551s, 6116s, 2116s, etc.
Happy to expand on this further if people are interested, but I would need to know which CMOS RAM you are using and a schematic of the device as some applications of 5101s are not compatible with the current NVRAM layouts.John :-#)#

[gwslotting]

With reference to Paul post on chip backup, I bought two different EPROM programmers, a few used 2716 EPROMs (new ones hard to find cause they don't make them anymore.), I erase their contents with EPROM eraser. I also have anti static floor mats, wrist band and built a cable to connect to the ground of a house wall socket. (Yes, the neutral and hot prongs removed !) When I did my post here, my unit is not running. Now it is running fine with the execption of loud grinding noise at the end of every pull/spin.  See my other post on "loud grinding noise"


I have been debating whether I should pull the 3 EPROMS (on my MPU board) and make backups. But really worry about 36 year old EPROMS when pulling them out. I have to bet against these EPROMS are living on borrowed time as they are designed only for 10+ years... 


Which way would you go.... ? 


Outright buying and selling EPROM contents within NLG forum are forbided. I asked these questions before and all the senior member and officials said no no. (See my other post on copyright). So it would be difficult even to find replacement EPROMs or buy the codes. Besides, there are so many versions of IGT Aristrocrat models that one must find the exact model EPROM, or be good at assembly language to modify the EPROM codes...