dx7 is dead

[gladish]

I tried charging my transmitter with an electrify triton 2 using a j4 adapter, which I was told to use by some guy at the local hobby shop. I'm certain I configured the charger to the right specs for the batter, and set the charge to 1 amp. After about 40 minutes. I stopped the charge and switched the radio on. Everything appeared fine, so I shut it off for a couple hours and now it won't turn on. When I put the triton charger on it, it complains about no battery. The a/c adapter that came with the radio doesn't turn it's l.e.d either. Is this an overcharged battery? What could have happened?

[Jermo]

:dontknow Sounds like a bettery issue. Try to charge it overnight with the correct charger. NiCads are a bit different than lipo. I'd go back to the LHS guy and tell him. If you followed his "advice" 100% then he gave you bad advice. No idea since I use the stock charger.
Jermo

[gladish]

The battery in my dx7 say 9.6v aa 1500 ni-mh. I was expecting nicad. I hope it's not marked wrong. When I plug the stock charger in, it doesn't appear to do anything. The l.e.d indicating that it's charging the transmitter doesn't light up..

[Jermo]

I mis-stated..ni-mh is correct. no idea. Take it to the LHS and let the guy figure it out.
Jermo

[capebob]

I'm not sure about the Spektrum line, but the JR, who manufactures the transmitter for Spekturm, puts a fuse in most of the charging circuits they make. Open it up and see if it has a fuse. I'm use JR radios and I've never had much luck fast charging a JR transmitter battery. If I need to fast charge a JR transmitter battery I remove the battery from the transmitter.

Bob

[DavidH]

I agree with Bob. It is most likely the fuse has blown in the radio. Since JR manufactuers the radio. I would think it has a fuse like the JR radios.

David

[gladish]

I'm not sure about the Spektrum line, but the JR, who manufactures the transmitter for Spekturm, puts a fuse in most of the charging circuits they make. Open it up and see if it has a fuse. I'm use JR radios and I've never had much luck fast charging a JR transmitter battery. If I need to fast charge a JR transmitter battery I remove the battery from the transmitter.

Bob

I considered this initially and after first inspection did not see any fuses. I just opened it up the tx case and yes, a .3A fuse is blown. It's right in the middle, under the top circuit board that the antenna attaches to. This circuit board doesn't necessarily have to be removed to replace the fuse, but it's a lot easier to get at the use by taking this board off.

The interesting thing is that it looked as though it worked for a good 30 minutes or so at 1A and actually charged. The transmitter initially turned on, but on the second shot it didn't. I'm hoping that the fuse really did it's job and protected the radio from damage. I'm now wondering if it's safe to use that battery again. There's really no need to fast charge, I just wanted to see if I could get more use out of the charger that I bought.

I won't know if things work until tomorrow. I have get to Radio Shack for a replacement.

[DavidH]

You sure the charge adapter you was using from the charger was the right polarity.

Most radios the center pin is positive and the outer shell is negative.
On your radio the center pin is negative and the outer shell is positive.

If you used the wrong polarity that would blow the fuse. But usually it does it as soon as the wrong polarity is applied.

Just to check the radio to see if it still works. I would take a test lead and connect across between the fuse holder. Then turn on the radio and see if it comes on.
If it doesn't and the battery is good. Then something happened to the radio. But I would think that nothing happened to the radio. That is why the fuse it there.

David

[pcool69]

I had the same problem. Replaced the fuse with a 3 amp fuse (all I had at the time) and it works fine. Probably not a good idea! I flew with the 3 amp last weekend but plan on getting a .3 amp before the next charge.

What is interesting is that I have charged my radio with the triton at .5 amps at least a dozen times prior to the blown fuse. I even cycled the battery 3 times after the initial slow charge. From now on I will use .3 amps to charge.

Make sure you double check the polarity of the charging jack with a meter before your next charge.

[WillJames]

If that fuse is in your charging circuit it is probably 3A and not .3 I would bet.

[stevehonn]

Isn't Spektrums advice that you don't charge with the battery fitted at more than 1A? I've been charging mine at 1A using my Robbe Infinity 3 without any problems.

[pcool69]

Just hung up with Horizon and it is a 3 amp not a .3 amp.

[Highlander]

I used an old charger lead, reversed the polarity and charge my DX7 using the socket on the TX using my chamelion charger. Most of the good chargers will alert you if it detects the wrong polarity.

[gladish]

IReading the markings on the fuse is pretty difficult. It looked like .3A, but all the .3 A fuses that I looked at are marked in MAH not with a decimal. So you'll see 315MAH not .3A. Regardless, I put a 3A and and it's working fine.

[flunk]

It's a 3A fuse, that's correct. I use a (home built) JR charge lead to charge my battery in the transmitter. I charge at 1A with my Swallow AC/DC.