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Apex to repair or to replace


Oleg

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I need some advice. My Apex controller main module broke. So I have sent it to Neptune's and they said that the repair is going to cost $150. So I wonder is it possible to find used controller for less than that? Just main module. I do not need a display nor energy bar.

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Well I kind of know what went broke. When I removed it from the stand I felt something was rattling inside and there was smell of burned plastic so I opened it up and I found one of large capacitors just fell off and one place on the board looked like something burned. I took some pictures. I'll post them later.

My guess is that capacitors just should not fell off the board on quality product. But the warranty is over so I have no choice other then pay for repair.

 

Oleg, did Neptune tell you any more about what went wrong, or why?

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Wow, that seems expensive for a capacitor change.....those components are dirt cheap. I suspect you are paying for their time to verify that it is working properly after being fixed.

 

Darren

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They said the board is damaged so they are replacing entire board, in essence entire controller.

 

Wow, that seems expensive for a capacitor change.....those components are dirt cheap. I suspect you are paying for their time to verify that it is working properly after being fixed.

 

Darren

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...I took some pictures. I'll post them later.

It would be interesting to see the pictures.

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Looks like a fried power transistor. (Hard to say, though. I can't read the device part number or reference designator.) There was a ton of heat on that board. Even the battery lead is showing discoloration. The replacement was probably the best option. Was the capacitor that was rattling around blackened, too, or did it look pretty clean?

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Capacitor looked clean. I wonder if problem started because capacitor fell off or capacitor fell off because of the heat.

I also could not find the place on the board where that capacitor was. C51 looks like it can be one, but it looks clean.

 

Looks like a fried power transistor. (Hard to say, though. I can't read the device part number or reference designator.) There was a ton of heat on that board. Even the battery lead is showing discoloration. The replacement was probably the best option. Was the capacitor that was rattling around blackened, too, or did it look pretty clean?

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I hadn't noticed the capacitor in the top of the pictures. It looks like an axial-leaded device - it's hard to see, but it looks like there are leads coming out of both flats on the cap. If that were the case, it wouldn't fit in the space for C51, which is laid out for a radial-leaded device. Also, those through-holes look unused. I can't see, off hand, where it would have come from, though. It does look like it was exposed to the heat from the failed part, though.

 

Based on the surrounding components, the fried part looks like it might be a DC-DC regulator. There's also discoloration around pin 5 of U18, in the vicinity of R31 an inch or two away.

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(edited)

I hadn't noticed the capacitor in the top of the pictures. It looks like an axial-leaded device - it's hard to see, but it looks like there are leads coming out of both flats on the cap. If that were the case, it wouldn't fit in the space for C51, which is laid out for a radial-leaded device. Also, those through-holes look unused.

 

I thought so too. I'll open new one some day just to see where everything was.

 

Now I wonder more why it happened and how do I prevent it.

Edited by Oleg
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Oleg, I had a chance to open up an Apex and see what was there. Here's what it looks like inside:

gallery_2631296_685_97777.jpg

 

Here are my observations:

First, it's a radial leaded capacitor (not axial), 220uF electrolytic. It's on the output side of a low dropout 5V regulator, part number 1117-50, SOT-223 package. The capacitor has been tacked in between the output and common leads on the regulator during post-assembly rework. This was clearly done after production of most of the board was complete. It is likely there to absorb transients on the load side of the device. My guess is that it's there to absorb noise coupling in from the Ethernet or Aquabus data.

 

The quality of the primary assembly run is pretty good. However, the quality of the hand-assembly that was done afterwards (putting components like short jumpers, the battery, and the pictured capacitor) leaves something to be desired in my opinion. There are at least three issues that draw my attention regarding the rework quality. They are:

 

1) The failure to secure the retrofitted capacitor makes the solder joints susceptible to shock or vibration failure. While vibration should be minimal to non-existent in day-to-day operation, that is not the case during transport. An RTV or other adhesive can be used to secure it to the body of the adjacent data connector against which it leans.

 

2) The capacitor is tall and, in the assembly that I inspected, it was the second only to the LED in height. Unless this height is controlled, there is the possibility that the body of the capacitor can come into contact with the case lid. Any deflection of the lid, for example, gripping or squeezing the case in the vicinity of the capacitor may put stresses on the solder joint causing or initiating failure.

 

3) Flux residue from hand assembly and rework was not cleaned. That's the brown stuff that you see, for example, at the base of the capacitor. I'm amazed at that, personally, and believe that given the obvious care in assembling the rest of the board, that they did not take the time to clean off the flux. This can be a problem for a number of reasons. Corrosion is one. Many flux formulas are mildly corrosive and can degrade the quality of the board assembly over time. Another is affinity for water and conduction. Many fluxes are organic acids and will attract and hold water from the air, and may become mildly conductive causing electrical leakage and even metal migration.

 

It's possible, looking at the failure of your board that the flux residue is part of the failure mode of your board. It may have become conductive, or changed the load characteristics on the regulator IC, causing it to overheat. It's also possible that the solder joints on the capacitor failed and that a lead became trapped between the regulator's ground and the output pin, again causing the device to overheat and burn the board. In either scenario, the root cause of the failure would be a defect in their manufacturing and quality control processes. It's also possible that the capacitor failed. However, it's difficult to see from your pictures if there was an obvious failure of that device (for example, I don't see a bulging or split case in the pictures).

 

In my opinion, Neptune should get with their assembly contractor and insist on better standards of rework and quality inspection. As for the Apex that I inspected, I've cleaned the flux off (using an industrial flux cleaner) and have secured the added capacitor to the nearby data connector. Hopefully this helps avoid the failure that you've experienced.

 

As for your situation, I personally think that Neptune should not charge you for a replacement board. This is a quality failure - a latent defect in their manufacturing process that they need to address to improve their product.

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Thank you Tom for taking your time to look at that. I'll open mine to clean up those issue that you pointed out. I also wonder whether the replacement board is any better or different from what I had.

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Thank you Tom for taking your time to look at that. I'll open mine to clean up those issue that you pointed out. I also wonder whether the replacement board is any better or different from what I had.

My money would be on it being the same. However, take a quick look when you get it and let me know.

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LOL. In case you can't tell, I've been involved in designing and manufacturing electronics and have even flown a few things in space. Establishing root cause in failures is critical with the rigorous testing protocols that are required in that industry. Controlled (quality) assembly methods are critical as well. I almost expect to see visible amounts flux residue in some offshore commodity products, but am disappointed that I would see it in this product. I'm considering dropping a line to Curt (at Neptune) to at least try to bring some attention to this.

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I'm considering dropping a line to Curt (at Neptune) to at least try to bring some attention to this.

 

That's a very good idea. I did send him an email, trying to explore how and why this thing happened and what we can do to prevent those and of course to enquirer on the status of the repair. He replied with just they status of the repair, tracking number and such and completely ignored other questions :)

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That's a very good idea. I did send him an email, trying to explore how and why this thing happened and what we can do to prevent those and of course to enquirer on the status of the repair. He replied with just they status of the repair, tracking number and such and completely ignored other questions :)

 

One more question. Where can I find flux cleaner in NOVA? Radio Shack?

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One more question. Where can I find flux cleaner in NOVA? Radio Shack?

I'm not sure where you'd get it here. I'm sure there are places. I had some in one of our assembly labs at work, so I used some of that. You can find some on Amazon. In the past, I probably would have gone to Arlington Electronics or given them a call. However, I've not been there in over 20 years and they may not even be in business anymore.

 

The way I remove flux manually is to have a short bristled flux brush (I normally cut the bristles down to about 1/4" for added stiffness) and apply it to the circuit card with a kimwipe (you could probably use a good paper towel that doesn't fall apart easily) placed between the brush and the board. The wetting action of the flux remover dissolves the flux which is immediately picked up by the absorbent kimwipe, thereby cleaning the board of much of the flux residue. For flight projects, we have a special washer that's much like a dishwasher. It uses RO/DI water and we monitor the outgoing water until contaminants fall below a certain ppm and the water essentially runs clear.

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  • 2 weeks later...

Just so you're aware, Oleg, I sent a note to Curt over at Neptune about this matter this afternoon, asking him to forward it to the appropriate people in charge of quality at Neptune. I included both your photo and mine with that email. In it, I outlined my observations and recommendations, and included my opinion that you should not have been held accountable for a failure of this nature, despite it being outside the warranty period. While the last part may see little action, if any, I hope that they can and will fix their assembly procedure to take care of the sub-standard quality of their rework on this board.

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Curt got back quickly, letting me know that the circuit card design has been updated to eliminate the rework around that capacitor. That's a good thing (and it saves them money, too). Now, if they can just clean up the flux on the board, I think they'll have a better assembly.

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Thank you Tom. I have got my Apex back from repair. New board has the same hardware version 1.1 as old one. Although there is one extra capacitor (I think), the blue one in the middle.

It seems like it has more flux than old one. Here is how it looked before cleaning:

 

gallery_2632507_993_26366.jpg

 

gallery_2632507_993_70863.jpg

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