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Another DX7 BLANK SCREEN OF DEATH

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Old 01-08-2007, 06:18 PM
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Gryphon
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Default Another DX7 BLANK SCREEN OF DEATH

Hi all,

I am a fan of Horizon hobby products and I love my new Spktrum DX7. It has performed perfect in 6 outings and about 15+ flights plus numerous at home bench tests without even a slight wiggle on moving surfaces or a hiccup on the motor RPM.

Today, I turned on my transmitter to see the famous black screen of death that I have been hearing about but not really believing.

It's true there is such a thing and now I have it.

I tried to charge it with my computer charger set on 8 cell NiMh and using a correct adapter for JR radios that I have used with this radio before which does have the right polarity. It gave me error messages right away.

I pulled out the battery from my JR 8103 which read 10.0V before removal. When I put it in my DX7 I still had a blank screen.

I took the battery from DX7 and put it in my JR8103 and it read 10.4V so the battery was charged.

I thought that I had heard that during the blank screen the model may still be under control, so I tried to install a battery in my Electric model. non of the functions worked so it is not just a matter of the screen being blank, there is no signals leaving the trans,,,,,it is dead.

The lights on the (2) stock receivers supplied with DX7 that are mounted in the plane were off, they are normally on. I presume with no signal they are off...I'll ask Horizon to verify. But I'm sure both ends of the business will not be going out at the same time like trans and receiver.

I will try to contact Horizon.

I'm glad that I was not flying my high powered model at 125+MPH. I think Horizon should be happy too.

This is a bummer, the weather is perfect today and I have recently started flying after many months and now after about 15 flights I'm grounded again. DAMN....

Gryphon
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Old 01-08-2007, 06:57 PM
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zac dady
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Default RE: Another DX7 BLANK SCREEN OF DEATH

My dx6 also did this to me I've since sen it back to horizon. I wonder what is going on with them. What really blows is that my trex and five other airplanes are controlled by this transmitter. I hope they get this problem fixed. I'm just lucky it didn't do this in the air. I just got done flying left my transmitter in the car went out and got it that night put it on the charger next morning went to turn it on and blank screen. I'm still upset about it.
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Old 01-08-2007, 07:11 PM
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Default RE: Another DX7 BLANK SCREEN OF DEATH

I have similar "black screen" happening to my Futaba 8 channel radio. The root cause is that the NIMH battery being fast charged has a peak voltage that the radio can not take. The radio has been modified (by passing a diaode) to allow Sirrus fast charger to work.

The fix is usually pretty easy. Send to radio south to replace a part.

Switching back to Nicad battery and has no problem since.

In your case, make sure Horrizon can explain the root cause. Anything more fundamental that blowing a fuze is really a concern.

--qc

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Old 01-08-2007, 08:05 PM
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Default RE: Another DX7 BLANK SCREEN OF DEATH

I was not charging anything.

But while on the phone with Horizon, I remembered after fast charging a JR XP652 a few years ago, when I turned it on, I saw the screen come on and then pop, it went out. It was my fuse that had blown due to fast and overcharge situation.

So I said to the guy, can I open up the back and check the fuse without Voiding the WARRANTY. He said fine.

After the phone call, I opened it up and it looks to have an old automotive style round fuse but shorter, about 3/4" long. I believe it says 3A fuse.

I will change and see what happens.

But how the hell can I trust it now. If I over charged then fine, I will not do that again, but this happened for no reason.
Charging happened about 10 days ago and since I've flown 5 times in 2 days with the trans left in on position for several extra minutes each time.

I hate losing confidence in my parts. That is why I didn't want to fly with 72MHZ radio for the last 7 months.
And now this….

Later
Gryphon
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Old 01-08-2007, 11:06 PM
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Default RE: Another DX7 BLANK SCREEN OF DEATH

I would be very cautious about the service at radio south. I have a jr 8103 that I sent them back in Sep. for routine checkout and it was returned with wrong/different antenna and no working screen. When I called them they said to send it back so they could repair it. I called back on two occasions to check on the progress and they said that the LCD was backordered after the second call. I waited an additional couple of weeks and called Horizon to investigate this and they confirmed that the LCD's are backordered and that they may not be reproduced indefinately [&o]. I decided to call Radio South again to try to work this out since the radio was fine to begin with and I've been without it for over 4 months. I suggested that they keep the Tx and return the aluminum case(new), Tx battery(new), Rx and my $150. The lady on the other end laughed and told me to call back later and see if I could make that happen! I'm very dissapointed about this and I can't believe that they have been around so long and treat me with this kind of service. I intend to get my property and money back.
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Old 01-09-2007, 12:47 AM
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Default RE: Another DX7 BLANK SCREEN OF DEATH

The fuse can be checked out with a multi-meter. It should bave 0 zero resistence. If the reading is infinite, it has been blown.

I read somewhere that the DX-7 has the LION battery. Is that true? If so, I wonder if the charger is OK. Normally, each LION or LIPO cell should not be over 4.2v after fully charged. An overcharged LION or LIPO battery is pretty dangenous.

--qc
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Old 01-09-2007, 01:15 AM
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Default RE: Another DX7 BLANK SCREEN OF DEATH

The fuse is blown right down the middle, no testing needed.

This was easy to see.
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Old 01-09-2007, 04:37 AM
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Default RE: Another DX7 BLANK SCREEN OF DEATH


ORIGINAL: nonstoprc


I read somewhere that the DX-7 has the LION battery. Is that true? If so, I wonder if the charger is OK. Normally, each LION or LIPO cell should not be over 4.2v after fully charged. An overcharged LION or LIPO battery is pretty dangenous.

--qc
It's a Ni-MH. The Battery mine came with is labled as Ni-MH AA 1500mAh 9.6V
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Old 01-09-2007, 10:12 AM
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Default RE: Another DX7 BLANK SCREEN OF DEATH

OK. Same problem as my Futaba 8UP. I recall Radio South also replaced a voltage regulator (a small component). Maybe DX7 does have such a device.

now we know how bad nimh batteries can be.

--qc
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