Replacing the Sherman controller board without complete disassembly nor modification.

[null]

Thanks to previous work on the subject I was able to find a way to replace the Sherman controller board without complete disassembly or modification. Other methods have their own merits, ie better access by @fbhb .

Order can be somewhat changed:

- Remove the trolley assembly, the stems are held by two clamps between the batteries. This way you dont need to remove the handle.
- Open the top and put the LCD on the side so you dont have to unplug it yet.
- Unplug the batteries and drain the capacitors by turning on with the LCD, unplug everything you can access.
- Release the front light jack socket (square nut) and pull it out as far as it goes. This allows to lift the front of the heatsink up.
- Unscrew the 4x screws holding the heatsink to the shell.
- Loosen the two top screws of the shell (one on each side), this to make the heatsink less tightly clamped.
- With the help of a lever (some flat strong piece), carefully wiggle the board upwards, a bit from each side.
- When the back is stopped by the jack socket, pull upward at the front, forward and wiggle it loose.
- Disconnect the rear connectors if you didn't get them yet.

Consider putting some silicone in the joint between the shells to limit water ingress from the wheel well.

When mounting the new board the heatsink was a tiny bit longer that the first one, making it difficult to push in. It helped to shave off a bit of the front and back edges of the shell (which separate the airflow and the board area) with a box cutter. They are slightly tapered anyway (for unmolding) so you're just removing 1mm or so in the corners.

 

Front jack socket pulled out to liberate the board. See the shells have a little gap from not being clamped.

 

Lifting up the board, a little at a time. Trolley assembly is removed.

Silicone on the joint:

 

Edited March 18, 2021 by null

[fbhb]

Hey @null glad to see your replacement control board finally arrived and thanks for the mention regarding my mod to allow much easier access for board removal!  Your method will definitely be a great help to owners that want to go that route, so thanks for sharing this with the community.

The fact that I went ahead and did my mod for much easier access will be prove to be very useful for me once a second replacement board actually arrives, although I had Not exactly planned on needing to get back in there so soon!  

As we have discussed previously, I'm still waiting for confirmation from Veteran on the way forward with how they will address my control board failing for a second time due to the "flaky" 5A YZ-Power charger issues.  I'm not sure if anything will eventuate regarding the build quality of the 5A chargers themselves, but it would be a great step forward if a safety measure could be incorporated into the Sherman's firmware to prevent a faulty charger taking out the wheel's control board!

Anyway, I hope your Sherman remains trouble free now that you have the New board fitted and a reliable charger to use - please let me know how you go on?

Edited March 19, 2021 by fbhb

[null]

5 hours ago, fbhb said:

The fact that I went ahead and did my mod for much easier access will be prove to be very useful for me once a second replacement board actually arrives, although I had Not exactly planned on needing to get back in there so soon!  

Yes you got use of your mod faster that we would have hoped for! The new board might ship faster this time at least..

I didn't contact Veteran to report the issue, but should probably to make sure they hear it.. Whatever the issue was we havent seen as many boards killed by chargers elsewhere. I suppose other e-char issues might also be linked to flaky charging.

The replacement charger just arrived (a C1200) I'll do a little overview and cross fingers that it works well

Edited March 18, 2021 by null