EB832 Attempting to Communicate with Apex (Bootloader Mode)

_AV

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Some of my previous repairs:

And as always, uncensored, updated and corrected versions of my repair articles are a quick internet search away.

In our previous EB832 repair, we covered the most common issue with EB832: power bar not controlling outlets due to very low-quality parts used within the unit.

This time, I have another EB832 a fellow reefer mailed me for a repair service with a different but common problem: EB832 gets stuck at “The EnergyBar 832 is in bootloader mode and is attempting to communicate with an Apex base unit” while flashing orange rapidly.

The symptoms of the problem are very simple. When plugged into a power outlet and Apex over aquabus cable, the power bar flashes the orange Neptune logo very rapidly, but never attaches to Apex and does not show up in the list of Apex modules. In some instances, when not plugged into Apex, the EB832 may go straight into the fallback mode with the Neptune logo flashing slower and some outlets showing as ON on the indicator panel.

To understand the reason for this behavior, we first need to understand what the EB832 is trying to do on power on. What Neptune calls the “bootloader mode” for EB832 is, in this specific case, the waiting to hear from Apex head unit so that the EB832 can be attached as a module. It will continue flashing orange rapidly until it either hears back from the head unit or times out and goes into the “Fallback Mode”. There are several reasons the EB832 cannot communicate with the head unit, for example: the AquaBus cable is bad, corrosion on USB ports, etc. But those issues are usually very easy to verify by swapping cables and ports. And if nothing helps, the problem is somewhere deeper.

How deep? Let’s find out.

After some basic troubleshooting we determined that:
  • Apex head unit works correctly.
  • Aquabus cable is good.
  • EB832 port is in good condition. Still no communication when plugged into other aquabus ports on EB832.
From the above, we conclude that the issue is almost certainly with the EB832. Since EB832 communicates with the head unit via a USB-like physical interface, it would be useful to trace the connectivity on board of the EB832. It takes us to this small component.

1615491022449.png


This is a CAN transceiver chip that aggregates the signal from all aquabus ports and sends it off to the main controller for processing. This very same transceiver is installed on ALL Apex modules including the head unit. This transceiver is our first gate from the aquabus port and into the EB832. It is not uncommon for this component to fail, especially if there was any corrosion on the port which might have shorted the wires. After all, unlike USB, AquaBus carries 12V on the pins next to the data pins.

At this point we could just try replacing this transceiver, but for the purpose of this article, we will take a step further and verify that the problem is indeed with this component without removing it from the board. This can be easily done with an oscilloscope and also with a logic analyzer. We know that the input signal is going to be a CAN encoded serial and the output is straight serial going into the UART on the controller. Thus, we could look at the input on the CAN side from the head unit and expect a decoded serial output on the Serial side of the transceiver. For this, we will build a very basic circuit where we connect jumper wires from the transceiver over to the logic analyzer. A small breadboard is not at all necessary, but it is used just in case the problem is even deeper and some additional testing is expected.

1615491065555.png


0006.jpg

By now, we know that EB832 is waiting for a command from the head unit. It is reasonable to expect some signal coming in on the CAN side first.

CAN.JPG


Indeed, we observe some activity at an interval of less than a second. This is our head unit sending the probe to EB832 and expecting it to return an ACK.

But the ACK never comes back…

Now that we know that the input signal makes it to the transceiver, let us see if it gets decoded on the serial side.

0005.jpg

serial.JPG


And the answer is no. The transceiver receives the data but never decodes it on the other side. The transceiver is indeed bad and needs to be replaced. We previously verified that the transceiver gets adequate power to do its operation.

It is not clear to me why the transceiver failed. It is quite possible that it failed due to a short between the 12v line on the USB connector and one of the two CAN data lines on the same USB connector. But I do see these problems pop up periodically.

Time to remove the faulty component.

1615491141849.png


We will clean up the pads and prepare it for a replacement.

1615491155897.png


The original transceiver had fewer features. What I had in stock has additional features controlled by additional signal over the pins and that is OK because the additional features can be disabled by keeping some pins disconnected.

Let us install the new chip and test with the logic analyzer on the serial side.

1615491176207.png


Now the signal on the serial side has a similar pattern as the CAN side.

serial_after.JPG


From this point, the signal from the head unit is making its way into the main controller on the EB832. After assembling and testing, we verified that the EB832 can now communicate with the head unit successfully.
 
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dank reefer

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This recently happened to my EB832. It ended up being the head unit that was causing the issue. But the culprit of it all was the Neptune Display screen that caused the head unit, and a Cor-20 driver to flake out.
 
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_AV

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This recently happened to my EB832. It ended up being the head unit that was causing the issue. But the culprit of it all was the Neptune Display screen that caused the head unit, and a Cor-20 driver to flake out.
Sounds about right. Did you end up replacing the head unit to fix this?
 

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Sounds about right. Did you end up replacing the head unit to fix this?
Yes. Neptune was able to replace it, and also the COR driver. Reason I know it was the screen was that as soon as I got the new head unit and plugged in the screen, the EB832 went into Bootloader/ Failback mode within seconds. After removing he display and rebooting the the Head unit it all went back to normal and haven't had an issue (knocking on wood) since then which was about 1 month ago.
 
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I'm willing to bet that the display shorted aquabus to 12v on the same connector. Historically, there has never been any protection on the CAN circuitry against this across Apex generations.
 

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Ha!
You'd know better than me. Ill send it to you and you can play with it if you'd like. The screen that is :D
 

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I have 2 eb832 that just crashed on me. One does not connect to the apex brain and just flashes. The second one connects just none of the outlets click on. Can u PM me the details to have you fix these.
 
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I have 2 eb832 that just crashed on me. One does not connect to the apex brain and just flashes. The second one connects just none of the outlets click on. Can u PM me the details to have you fix these.
PM sent.
 

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OMG _AV, I can't stop watching you videos, great work! You inspired me to dig up my broken EB832 as I have the exact same issue here, blinking light but never connects. Of out curiosity I pulled out my old oscilloscope and connected it to the can transceiver chip. I can see packets flying by on both can channels and serial. Oddly though the CANH channel intermittently goes to ground, CANL stays with its voltage range. Do the CAN transceivers do this when they're toast?
 

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Hi there and thank you for watching. :)

I have not run into this issue myself, but there's literally nothing else in this circuit on the CAN side. Unless you are having a short on the AquaBus/USB connector, it must be the transceiver. Are you getting anything intelligent on the serial side?
 

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Existence

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I checked on all the connectors looking for signs of a short but nothing sticks out. I tired connecting to the Aquabus and I'm not seeing those drops to ground when the eb832 is not connected, which I guess is good. The serial lines are showing traffic, but I don't have a decoder so I'm not sure if they are all valid frames.

Interestingly though, when I plug the broken EB in it emulates my other (active) EB832, switching on and off ports to match it. It doesn't show up in apex though, and remains blinking. Originally I though the IDs might have been the same but I don't think that's the case as it still doesn't work if it's the only EB plugged into the head unit. I wonder if the "switching" frames somehow bypass most of the Micro logic.

It's very weird.

BTW, when I was attaching wires I was laughing how easy you made it look, those things are TINY!
 
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I know that EB832 falls back into offline mode if it can't talk to the head unit. But I also observe periodically that it sometimes doesn't do that until plugged into aquabus. There are bugs in Neptune's protocol implementation, so I'm not surprised that odd things may happen on partial connect.

With that said, I'm struggling to come up with a test that doesn't involve swapping the transceiver. It's easy when you have spares, but harder if you have to order some and wait for them to arrive.
 

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Thanks for the insight. So true on the spares, I think I’m going to grab a couple of the can transceivers, I found these ones that look like a match SN65HVD232QDRQ1. Mine looks to be 5V. I think I will grab a bunch of CAPs too and replace them while I'm at it.
 

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Well all be, it worked! I replaced the CAN transceiver and it connected. Thanks for all the videos it really helped, plus I got to use a old hot air rework station I bought years ago which was just collecting dust. One less thing in the landfill! Now I think I will attempt to replace all the CAPs, I bought a bunch of higher temp Nichicon replacements so will give that a go.
 
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This is great. Job well done. Definitely replace all 4 electrolytic caps on the 12v PSU.
 

Existence

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Thanks! I got the CAPs all replaced and it seems to be working well.
I went a little crazy on mouser and bought a replacement Fan and new outlets receptacles too. The fan was easy but the receptacles are super difficult to replace. I got one off and replaced it but it requires a ton of force to pull the sockets off. You have to push pretty hard too to get them back on. Mine are only a bit corroded so I don't think I'm going to risk it to try and pull the others, seems like way to much force is needed on the PCB, unless there's a trick I'm missing.
 
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You'd want to use low melt solder to get those outlets out. Too much plastic and too much solder around to do it safe otherwise.
 
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