Navy_Flyer

Well - I hope I did not do something dumb, but of course I probably did. We're talking about a Futaba 7UAFS. First, I have a jumper across the diode so I can use my AccuCycle Elite without taking out the battery. Well, it finally came time to replace the Tx battery so I bought a 2100 maH NiMH. I had to add the connector. Years ago I replaced the spade connectors (that made me very nervous with somwhat tentative connection to the battery pack) with a 9V connector to match the pack. So, I put a 9V connector on the new pack. Even after "checking it twice" (I thought), I plugged it into the transmitter and switched it on. I got 11.2V - for about 1 second, then... dead. Nothing - no power, no nothing.

I think I may have hooked it up backwards [&o]. I haven't had the opportunity to take the back of the case off yet. Did I do irreparable harm? Or did I just blow the fuse...? ..... anyone ?

I took the battery out of the Tx and checked it on the voltmeter - still shows 11.5+volts.

Campgems

Navy, do you mean a conector like a transistor radio battery?? If so, deep six it and solder on a J connector. Those connectors tend to corrode and cause paroblems.

It sounds more like your battery is dead vs reversed, or a bad connection. If you plug in the charger, does it show a trickle charge when you first start it? If you have a volt meter, plug the charger leads into it and then plug the other end into your transmitter. You should show voltage. It will also show if your leads are reversed. Even though you show voltage on the battery, you need to put a load on it to see if the connections are good. A bad connection will show voltage, but as soon as you put a load on it, it will drop to near 0V. You can use resistor, about 30 ohms will give you around 350 MA draw which should be enough to show the condition of the connections. Just put the resistor across the volt meter leads.

Don

Navy_Flyer

Yes, a 9V battery connector - so as to 'directly' connect to the Futaba factory pack with 9V connectors on it. The original setup has flat metal tabs for the 9V 'pins' to touch, and I was not happy with that arrangement - because the battery did not fit tightly in its compartment. I found that if you moved the battery a bit back, away from the spade lugs, the connection would be lost, albeit momentarly - but enough to possibly lose a plane. Have had this 'mod' on it now since 1993-ish. Anyway - to your point - the battery pack I replaced it with shows good- and I can charge/cycle it outside of the TX. So - did I hurt anything in the TX except maybe the fuse? I have still not had a chance to 'go in' and look at it.

Navy_Flyer

Well, the good news is the only issue was a blown 3A fast burn fuse. Replaced it, and the TX is up and working fine. The bad news is that this episode has revealed a weakness in the connector. I think I will take your advice and put a J connector on it. The 9V connector had worked to a 'loose' fit on the corresponding battery pack connector, and I was getting an erratic indication on the Transmitter's built in ESV. So if there is a silver lining, the fuse caused a re-engineer of the connection. It was only a matter of time before I had a problem with an aircraft airborne! Timing is everything.[:-]

Robotech

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I love happy endings. Better a 3a fuse than an airplane.