FixReef is now also on YouTube!
https://www.youtube.com/channel/UCMAmpCr_0gSwhmTNGzXTPtg
Enjoy this repair, now in HD
I have previously done a fair number of water damage repairs. Electronic equipment and salt water do not mix well. This is especially a significant problem when said equipment is fairly expensive.
In this repair, I'm going to attempt to restore an Apex DOS after a significant water damage.
A typical water damage repair involves cleaning up corrosion around components and connectors, replacing burned power converters, etc. This repair is no exception.
However, what makes this repair unique is... the brain surgery.
But let's not get ahead of ourselves.
This repair started with a very simple observation: the main board of this DOS unit has seen some salt water:
Specifically, around the 24v ports:
Some SMD components corroded off and gone missing entirely:
Voltage regulator, capacitors... you name it:
But all of this can be fixed or replaced. After some ultrasonic cleaning, the board came back in a much better shape:
But that gaping crater, where the 24v connector used to be, is still a major problem.
Indeed, a major short of high current 24v rail and aquabus data pins to ground caused most traces around the connector to burn away. There is nothing to attach the connector to anymore.
The solution is to run wires to the other side of the board and connect pins to remaining traces:
But this was just the beginning. As it typically happens, a short on aquabus permanently damages the transceiver circuit.
The chip has to be replaced anyway, as it was significantly corroded as well:
+
It's being replaced with a brand new component:
However, after all missing components were replaced, all corrosion removed, all small burned parts cleaned out and fixed, one major issue still remained.
After fixing many of these units, I know what kind of power consumption to expect when powering up the board.
In the case of this board, it was using way more current than I would have expected.
I knew where to look for answers:
As I started poking around the main controller, I quickly realized that the main controller is gone. First, status LEDs on the board were off. Second, the controller was getting very warm to touch.
This is where it is important to pause and discuss a few things first.
It is not at all a surprise that the controller is blown. After all, it should be expected that the water damage would cause the input 24v power to conduct across many sensitive components.
It is unfortunate that the controller is gone, this doesn't happen with every repair, however.
But this is also when this repair gets interesting.
Neptune uses common Atmel AVR controllers for most of their Apex modules. Same AVR controllers are used in a variety of arduino boards, for example. They are functional, very popular, easy to program and inexpensive.
These controllers store custom firmware code and act as the main brain of the module.
Unfortunately, this also means that I can't just buy a replacement Atmel controller, put it on the board and expect the module to work as new. After all, the new replacement controller must be programmed first.
As you can imagine, Neptune does not make it easy to obtain the firmware. It is still quite possible, just not as easy as downloading it from their site.
Moreover, the firmware on each Apex module can be updated. That's why we see different firmware version numbers in Apex list of modules page.
On one hand, this makes obtaining firmware easier, on the other hand... remote firmware update means that there must be a bootloader.
This bootloader is permanent and cannot be updated. Therefore, it is usually not being distributed.
Neptune also locks the controller from any firmware memory reads.
All of this, so that a third party repair will not be able to repair and replace the brain of the module, unless a donor board is available.
But FixReef.com is not your typical third party repair, so we will press on with replacing the main controller anyway:
Once removed, the area is cleaned up and prepared for the new controller:
Now, a brand new controller is installed in place:
Every Apex module comes with a programming 6 pin header, positioned typically near the CPU. It is there to perform post production code provisioning.
I'll use this pin header to program the brand new chip using the AVR development board:
Finally, after reprogramming, the status LEDs light up correctly. The board communicates with the head unit, DOS is being recognized as having firmware version 007:
And more importantly, it can be controlled:
The brain surgery on this DOS module is now complete and the module is back in operation.
Stay tuned for more exciting challenges. Next up is a common Kessil A360X sporadic shut off issue.
https://www.youtube.com/channel/UCMAmpCr_0gSwhmTNGzXTPtg
Enjoy this repair, now in HD
I have previously done a fair number of water damage repairs. Electronic equipment and salt water do not mix well. This is especially a significant problem when said equipment is fairly expensive.
In this repair, I'm going to attempt to restore an Apex DOS after a significant water damage.
A typical water damage repair involves cleaning up corrosion around components and connectors, replacing burned power converters, etc. This repair is no exception.
However, what makes this repair unique is... the brain surgery.
But let's not get ahead of ourselves.
This repair started with a very simple observation: the main board of this DOS unit has seen some salt water:
Specifically, around the 24v ports:
Some SMD components corroded off and gone missing entirely:
Voltage regulator, capacitors... you name it:
But all of this can be fixed or replaced. After some ultrasonic cleaning, the board came back in a much better shape:
But that gaping crater, where the 24v connector used to be, is still a major problem.
Indeed, a major short of high current 24v rail and aquabus data pins to ground caused most traces around the connector to burn away. There is nothing to attach the connector to anymore.
The solution is to run wires to the other side of the board and connect pins to remaining traces:
But this was just the beginning. As it typically happens, a short on aquabus permanently damages the transceiver circuit.
The chip has to be replaced anyway, as it was significantly corroded as well:
It's being replaced with a brand new component:
However, after all missing components were replaced, all corrosion removed, all small burned parts cleaned out and fixed, one major issue still remained.
After fixing many of these units, I know what kind of power consumption to expect when powering up the board.
In the case of this board, it was using way more current than I would have expected.
I knew where to look for answers:
As I started poking around the main controller, I quickly realized that the main controller is gone. First, status LEDs on the board were off. Second, the controller was getting very warm to touch.
This is where it is important to pause and discuss a few things first.
It is not at all a surprise that the controller is blown. After all, it should be expected that the water damage would cause the input 24v power to conduct across many sensitive components.
It is unfortunate that the controller is gone, this doesn't happen with every repair, however.
But this is also when this repair gets interesting.
Neptune uses common Atmel AVR controllers for most of their Apex modules. Same AVR controllers are used in a variety of arduino boards, for example. They are functional, very popular, easy to program and inexpensive.
These controllers store custom firmware code and act as the main brain of the module.
Unfortunately, this also means that I can't just buy a replacement Atmel controller, put it on the board and expect the module to work as new. After all, the new replacement controller must be programmed first.
As you can imagine, Neptune does not make it easy to obtain the firmware. It is still quite possible, just not as easy as downloading it from their site.
Moreover, the firmware on each Apex module can be updated. That's why we see different firmware version numbers in Apex list of modules page.
On one hand, this makes obtaining firmware easier, on the other hand... remote firmware update means that there must be a bootloader.
This bootloader is permanent and cannot be updated. Therefore, it is usually not being distributed.
Neptune also locks the controller from any firmware memory reads.
All of this, so that a third party repair will not be able to repair and replace the brain of the module, unless a donor board is available.
But FixReef.com is not your typical third party repair, so we will press on with replacing the main controller anyway:
Once removed, the area is cleaned up and prepared for the new controller:
Now, a brand new controller is installed in place:
Every Apex module comes with a programming 6 pin header, positioned typically near the CPU. It is there to perform post production code provisioning.
I'll use this pin header to program the brand new chip using the AVR development board:
Finally, after reprogramming, the status LEDs light up correctly. The board communicates with the head unit, DOS is being recognized as having firmware version 007:
And more importantly, it can be controlled:
The brain surgery on this DOS module is now complete and the module is back in operation.
Stay tuned for more exciting challenges. Next up is a common Kessil A360X sporadic shut off issue.
