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Old Aug 07, 2010, 07:35 AM
Registered User
Varazdin, Croatia
Joined Aug 2006
21 Posts
Help!
Headplay goggles - reversed polarity

Hi everybody,
I reversed polarity on the battery that powers Liberator of my Headplay goggles. One element exploded, as you can see on picture below. I would like to know whether anyone has been in similar situation. What are my options? I emailed Headplay’s support and am awaiting their reply.

Thanks for help,
Zoki
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Old Aug 07, 2010, 08:50 AM
ΜΟΛΩΝ ΛΑΒΕ!
Pennsylvania, U.S.A.
Joined Feb 2005
236 Posts
Well, at the very least, you fried a simple capacitor. The problems is that surface mount stuff can't take a lot of abuse, so I would guess that something else got nailed as well. Usually caps are used as a noise filter of sorts in the input stage, so it's not necessarily a "Make or break" component in that context. I'm afraid there's just no way to tell for sure, without replacing components.

You could throw a regular cap in there by leaving the "Legs" long and letting the cap stand up in the air. The problems is that you don't know the capacitance value anymore, since it's destroyed. It's a guessing game at that point.

If you aren't skilled at electronics/soldering, I would suggest sending it back to the Headplay folks for repair. If you have a friend that's good with electronics, you might want to ask for a big favor about now.
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Old Aug 07, 2010, 09:37 AM
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Australia, QLD, Gold Coast
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It's not a capacitor, It looks like it was an inductor, named L11, for capacitor should be named Cxx.
In the very first look it seems it connect the negative polarity of the input power jack/battery to ground of board.

Check it if it is so then,I think just connect two point together it will be fine, I recommend you to use a 300mA~500mA fuse and put it between two connections.
If it works, fine, otherwise you have some other parts failed.
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Old Aug 07, 2010, 10:42 AM
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Varazdin, Croatia
Joined Aug 2006
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Thanks for replies,
I will wait until monday to get Headplay's answer, and then decide what to do next. Local computer shop took Liberator and they will try to check which parts are burned on monday, so I can't try anything until monday.
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Old Aug 07, 2010, 02:00 PM
ΜΟΛΩΝ ΛΑΒΕ!
Pennsylvania, U.S.A.
Joined Feb 2005
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You're right. Looked like a "C" to me, with part of it obstructed by the carbon staining. When comparing it to other caps, it does look different. So yea Definitely an inductor. I still say that it's very likely that something else probably took a hit though. It's the ones that don't have any obvious marks that always come back to bite you.
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Old Aug 10, 2010, 01:00 AM
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Australia, QLD, Gold Coast
Joined Aug 2007
856 Posts
I have a broken left visor mirror/glass.
I am willing to buy your goggles if you could not fix the liberator box.
http://www.rcgroups.com/forums/showthread.php?t=1289401

Habib
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Old Aug 10, 2010, 02:00 AM
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Netherlands, NH, Edam
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Headplay couldn't even mount a $0.20 reverse polarity protection diode? Geezzz ...

Cheers,

Sander.
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Old Aug 10, 2010, 02:05 AM
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Australia, QLD, Gold Coast
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Quote:
Originally Posted by ssassen View Post
Headplay couldn't even mount a $0.20 reverse polarity protection diode? Geezzz ...

Cheers,

Sander.
That sucks, I agree, its a DIODE.

Habib
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Old Aug 10, 2010, 04:08 AM
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Varazdin, Croatia
Joined Aug 2006
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Hi,
here is Headplay's reply on my email.

Zoki,

I showed your pictures to one of our engineers. He would like to see a picture of the complete setup you had connected at the time, and he may (or may not) have some recommendations for you going forward.
Repairing this circuit board would be difficult at best, and may not be possible.

Headplay does not have any direct to customer sales at this time, but previously we had not sold the Liberator and Visor as separate products, only as components of the Headplay Personal Cinema System (PCS).

Thanks,
Headplay Technical SUpport


I sent them back more pictures of setup so now again waiting for reply.

Zoki
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Old Aug 10, 2010, 11:10 AM
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Germany
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I am very interested, because I have the same problem with my headplay like you:

my problem


Could you repair it?
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Old Aug 10, 2010, 11:27 AM
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Varazdin, Croatia
Joined Aug 2006
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Quote:
Originally Posted by CyberCrash View Post
I am very interested, because I have the same problem with my headplay like you:

my problem


Could you repair it?
I saw your post.
I will post Headplay's reply once i get it, hope they will have some kind of solution. If not, we will have to try to solve problem ourselves.
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Old Aug 10, 2010, 12:09 PM
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Hey Zoki,
thank you. Maybe they tell you how to fix this.

When did you write them?
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Old Aug 10, 2010, 12:38 PM
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Varazdin, Croatia
Joined Aug 2006
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Quote:
Originally Posted by CyberCrash View Post
Hey Zoki,
thank you. Maybe they tell you how to fix this.

When did you write them?
Well, I wrote them yesterday, now is 9:30 AM in Los Angeles, they'll probably reply by the end of working time.
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Old Aug 18, 2010, 03:51 PM
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Varazdin, Croatia
Joined Aug 2006
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After a lot of waiting i finally got headplay's reply. As I promissed, I am posting complete reply.

Zoki,

Here is the result of our engineers investigation into this issue. It doesn't sound like it can be repaired.


"The problem is due to connecting reverse power to the adapter input when the AV input is connected and powered from the same source (see attached diagram). Under these conditions, the AV connection is providing interconnection between the Liberator and camera where the GND level is different:
- the liberator has battery positive connected to GND, -the camera has battery minus connected to GND.
This results in the interconnecting cable providing a short across the battery through the Liberator. L11 inside the Liberator is the point that interconnects the AV GND to the power adapter minus input. This is normally only carries current from AV signals (in the order of a few milli-amps), and is not capable of withstanding the current from a shorted battery (many amps). This is why L11 was destroyed. Once L11 became open-circuit, reverse voltage would be applied across the AV input ICs (which connect to both input power minus and AV input GND); this would cause these ICs to be destroyed. When correct polarity power was later applied to the Liberator, the power input fuse would be blown due to the damaged ICs.

The Liberator does provide reverse-power protection on its power adapter input. However, it does not provide protection against connecting AV equipment with a different power-connections for AV GND (nor does most equipment that I know of)."




I would also like to use the opportunity and ask if someone is willing to sell the Liberator.

Best regards,
Zoki
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Old Aug 18, 2010, 04:13 PM
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Germany
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732 Posts
I received a reply myself:


We have heard from a small number of FPV users that have experienced this issue. It is likely that you accidentally created a short of the external battery burning the L11 component on the circuit board. If you were using the battery to power your receiver as well as the Liberator this may be the cause, or possibly a common ground. Regardless of the cause, it wouldn't be an easy fix. You might be able to bridge the L11 on the circuit board but I can't really recommend this as a fix as you would be removing the protection that L11 provided.



But what can we do not to encounter the same problem again?
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