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Replacing MTH batteries

MTH's original ProtoSound and ProtoSound 2.0 systems can create great anxiety when the systems backfire. The culprit is often a component that's hardly hi-tech. It's the battery. Read on more.
By Jim Riccioli
Published: January 22, 2010
The age of miniscule computer chips has delivered sweet sounds to modern toy train locomotives. But such systems can add a sour note when they start acting "funny."

MTH's original ProtoSound and ProtoSound 2.0 systems can create great anxiety when the systems backfire. The culprit is often a component that's hardly hi-tech. It's the battery. Read on more.

The culprit

Although MTH circuitry continuously recharges the battery whenever you run your locomotive, the original factory-installed NiCad (nickel cadmium) battery deteriorates with age until it can no longer hold a charge or reach its full voltage capacity, no matter how long you charge it. At this point, the battery must be replaced.

MTH reports that fully a third of the locomotives returned for repair could be serviced at home by recharging or replacing the battery.

How do you know the battery in your locomotive is going bad? If your locomotive is several years old, the sounds stop when you interrupt power, the whistle or horn are distorted below 10 volts, or the locomotive will not sequence through forward, neutral, and reverse properly, your locomotive likely has an undercharged battery.

In MTH's sound systems, a bad NiCad also can create a tech-y problem. As an aging or long-idled battery fails to deliver the voltage needed to allow the sound system to power down properly, the locomotive's computer chip can get "scrambled" - basically, the software becomes jumbled by the electrical irregularities so that the system can no longer think properly. The net effect is usually that the locomotive stays locked in one direction, or the sound sequences become corrupted. If that's the case, there's nothing you can do to get it working properly again except to send the locomotive to MTH, which simply replaces the bad chip.

However, the problem can be avoided entirely by paying attention to the battery before it has a chance to scramble your circuit.

The fix

MTH has this suggestion: If you haven't run a ProtoSound-equipped locomotive for a few months, charge the battery before running the locomotive and cycling through the various sounds. You can charge the battery by removing it and sticking it in the appropriate battery charger (such as MTH no. 50-1005 or battery chargers sold at Radio Shack and Wal-Mart, among other places). Or simply put the engine in neutral on the track and turn the throttle to 15 volts for 14-16 hours. You can also do a quick charge for an hour using the same procedures and then test the locomotive to see if the battery and sound system are functioning properly, and then finish charging it later.

If the battery is bad, obtain a new NiCad from MTH or replace the NiCad with an 8.4-volt 150-mAh Nickel Metal Hydride (NiMH) rechargeable battery. NiMH batteries don't usually exhibit the "memory" problem of older NiCads. If you've ever had a cordless vacuum or rechargeable screwdriver "go bad" you've faced this problem before. MTH lists a Radio Shack NiMH battery (stock no. 23-529) that's suitable, but some operators prefer Rayovac's NM1604-1, available at Wal-Mart and other retailers. (Beware of 9-volt rechargeable batteries that don't deliver at least 8.4 volts when fully charged. Energizer only lists a 7.2-volt rechargeable NiMH battery, which is not adequate for MTH's system.)

How to do it

Removing the old battery and installing a new one is easy. The battery is attached to the typical wire harness/connector that you see in appliances which use 9-volt batteries. Simply charge the new battery as directed, remove the locomotive shell, and have at it.

Like MTH, you may want to use a piece of mounting or servo tape (double-sided padded adhesive tape such as the type used in radio control models available at hobby shops) if you want to secure a loose battery in its proper position. Refer to your locomotive's manual on how to remove the shell.

MTH's design generally requires that the battery be present for the locomotive to work at all. (There are some exceptions with MTH ProtoSound-equipped locomotives made before 1998). So, if you own an MTH locomotive with sounds, you'll have to deal with the battery sooner or later. Sooner is better.

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How about the B.C.R. replacement? Once in you never half to replace the battery agin!
5 stars
just the info. I've been looking for to fix a locked in forward engine. Thanks
all charged up about the info- right on
Phil G., Contact the good folks at MTH customer service ( early afternoon EDT is best) and ask to speak with a service technician. They will be glad to talk you through the shell removal. Even though I only live a half hour's ride to MTH headquarters in Columbia,MD, I have always been able to solve any issues over the phone,right at my home workbench! P.s My favorite source of Tinplate Traditions trains& stuff is Sidetrack Hobbies in Leonardtown,MD( check em' out!
Hi Phil, I looked at the manual (available on the MTH website) and I'll be darned if I could find the "how-to" part about removing the shell. While I might suppose the screws holding the boiler on the model might be obvious, I generally hesitate before I start unscrewing things at random. You might want to try and contact MTH service for help. FWIW they also have the manual for the early ProtoSound engines online and they contained the notation that if the battery needed to be changed, contact MTH to return the product for repair.
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