bignasdy

well, I'm a dumbass. I was going to help at the clubs (yes..I joined one....) kids fly free day, with my trusty old senior falcon testbed, which I was breaking in a new mds.78 on, when I thought how nice it would be to quick charge my futaba through- out the day. I downloaded the diode jumping pictures from ace rc's website, and soldered the wire in there just like it says to do. Everything checked out fine, and a quick charge was accepted fine. The range check was normal. I got to the feild set up with a student, and went for a takeoff. The plane was in fine trim, but took off straight up. Good thing I had the 78 on there ,ha ha. I had zero control. My baby flipped, rolled and flew a beutiful inverted flite the oppisite direction, about 2 hundred yards, and crashed full throttle into the trees. After about an hour, I found what was left of the plane I built in the 70s, and used to test radios and break in all my new motors.
I guess I just didnt solder correctly, and .......
I will never mess with my radios again. Never have in the past, dont know why I did it now. My advice is to buy a radio that will do what ya want it to do in the first place. The radio was purchased in 1990 and never had as much as a glitch before. Hope yall can learn from my mistake!
david
"ya gotta be smarter than the equiptment"

bignasdy

dont know what I was thinking man. I'll just pull the thing out to cycle it if I need to. thanx
d

EyeflyRC

My Feedback: (147)

You cannot use a peak charger fast or slow unless you jump the diode or access the battery through an auxiliary connector.

00hex

Why don't peak chargers work through the diode? It should still be able to read the voltage. It's putting current into the battery, the diode doesn't block that. The voltage will be about 0.6 V lower, but that shouldn't make any difference. Does the voltage drop across the diode vary and confuse it?

A warning - I doubt that the diode is very tough, I wouldn't try to fast charge it at more than 1 amp or so (which is pretty fast if there's no peak detection!). All diodes become light-emitting diodes if you put enough current through them! (I did this by accident once. Very interesting.)

Ladyflyer

My Feedback: (2)

Not at all likely any thing you did with the diode caused that crash. Must have been unfortunate timing. The diode is not even in the circuit when the power is turned on. If the battery took the charge ,the jumper worked.
You stand a chance of creating a problem ANY time you open the transmitter. Repeated plugging and unplugging the battery is FAR more likely to cause a power failure crash than the operation of jumping a diode. The battery connector IS in the circuit and IS a point of potential failure that can only become WORSE with repeated use.
I ELIMINATE the plug and solder the battery leads to the board directly. I always jump the diode. The direct battery connection does improve reliability a bit ,and EVERY bit towards improved reliability is a plus in my book.

Al Stein

Either way it's a sad thing to kill a Falcon... let me know if you need plans to build a replacement.

Ladyflyer

My Feedback: (2)

Almost as sad as not understanding what the problem was and repeating the crash wit a new plane :-)

b1rd37

Crewdog, Sounds like you may have created a cold solder joint, the resistance at that point can cause a lot of heat at high currant.

Jerry

FHHuber

Not sure about all radios... (not even all Futabas.) I have a couple of older Futabas that the charge jack IS active when the power switch is on. You can "piggy-back" an exernal battery to extend durration with the TX on. in that case, the diode prevents a bad external battery from killng the internal battery. (how to go for a durration record... almost no other use for this capability.)

I haven't checked if this works on my newer radios... yet.

Peak detecting chargers need to be able to check the voltage of the pack, and the diode can prevent that. (which is why many people want to jump the diode.) With the diode in the circuit, many peak detecting chargers will not even sense that the battery is there, and will cut out immediately. Also the diode prevents an ESV from working through the charge port.

Ladyflyer

My Feedback: (2)

The charge jack on all Futabas that are equipped with the "protection" diode is isolated from the internal circuitry by the power switch. The diode is on the opposite side of the switch from the side that powers the transmitter. The diode is never in the power path from the battery to the transmitter power input . The old G series were pretty much the same setup without the diode . I don't recall any Futaba aircraft radios in which the charge connector wasn't disabled when the power was on . The main reason Futaba put the diode in was to prevent a short circuit outside the transmitter causing a fire the REAL danger. The odds of hurting the radio with a reverse charge are low. The repairs usually require a new battery , a couple of voltage regulators and possibly a new charger. Nowhere near as costly as a small fire !

Futaba has seen the light and is now putting a cheap (inexpensive, about sevevty five cents !) solid state,self resetting fuse called a "Polliswitch" in some transmitters where the diode used to be. The polliswitch has near zero ohms resistance up to it's current rating . When the current thru the Polliswitch increases ABOVE it's rating the resistance increases and limits the current thru the device .This is basically what many of us have been doing right along with fuses. It protects against fires caused by short circuits external to the transmitter and still allows discharging and meter reading at the charge jack. A case where the "leader" finally followed !

Tim_Indy

I've always jumped the diodes in my Futaba radios so as to be able to peak charge them. One reason I've had zero problems is that I take a piece of regular servo wire (or servo extension wire), open it and use a SINGLE STRAND of wire (super fine) to bridge the diode. This acts as a fuse so that for normal peak charging up to almost 1 amp, the strand carries the current. Any voltage spike will immediately blow the fuse (strand) and you'll be right back where you started, with the diode back in the circuit.

Tim