QSI with battery question....

3 boards means it is a QSI OEM sound system. It should have a speaker in the fuel tank. Like a Proto-Sound 1 system, QSI OEM requires a 9v battery for proper function. The best way to test it is to charge up an 8.4 volt rechargeable NiCad and plug it in. The system has a charging circuit designed for NiCad batteries. You can use a 9v alkaline cell for short-term testing, but alkaline cells are not designed to be recharged and they should not be used with a charging circuit for very long. 

QSI OEM must be used with an 8.4v NiCad rechargeable. Some cheap "9 volt" rechargeables only have six internal cells and only put out 7.2 volts. The battery must be an 8.4 volt model with seven 1.2v cells internally. The QSI OEM charging circuit does NOT put out enough current to charge a BCR or a NiMH battery - you can only use NiCads in that particular system. Trying to run it with a BCR installed can blow the charging circuit. 

A QSI OEM system is a predecessor to Proto-Sound 1. It is easily identified by the three-board stack; a Proto-1 system only has two boards in the stack. 

I agree with above, except QSI continued to produce 3 boards sets for OM other than MTH and the newer versions had a beefer charge circuit so it will handle BCR.  G

Thanks for the reply guys.....yes there is a speaker in the tank so you pegged it.

What battery would be best to install long term??? I am conventional and have never worked on this QSI set up. Again thanks!

Any 8.4V with about a 150 mahr rating or better.  MTH/Energizer/Radio Shack etc...

Thanks! I have a new Energizer on hand...I'll check it! Thanks!

That's the first I've heard of any upgrades to the charging circuit. Art Boynton did upgrades for the undersized main power diodes; he did one for our museum a couple of years ago. Art told me several times that the charging circuit could not be upgraded. If they did upgrade the charging circuit, it's kind of odd that Art wouldn't have known about it, since he was their factory service rep. The QSI website used to refer all 0 gauge service to him at The Scaled Tin Rail. 

I thought his website did show the upgrade at a cost.  I talked to Art a few times.  I know the initial cut was no to BCR, but later that was changed.  The MTH boards were upgraded and many folks run BCR.  So I am not sure why the QSI board could not be upgraded.   G

I've used a BCR in many of my MTH proto 1 pieces, without issues. The one that did NOT like the BCR was the 1994 UP #5 GTEL 8500.  FWIW, I seldom, if ever use the volume all the way up in my stuff...except on the UP turbines.