AZEQ6GT Mount fried

[Garnimoa]

Can anybody point me in the right direction in either getting a replacement circuit board for my mount.

My transformer 12V 7.5A literally blew up and smoke billowed everywhere. No I wasn't trying to test my mount and video recording it for a Youtube clip.

Oh well. Eager to hear what you all reckon, I should do?

Cheers Gerald

[Rerouter]

Seems orion can supply a compatible one
https://www.cloudynights.com/topic/697061-i-blew-up-my-atlas-azeq-g-motherboard/

Are you sure the mount PCB is damaged, and not just the plugpack failed?

I personally cannot believe stuff that costs this much does not have reverse polarity protection based on that thread.... its 45c for a 20A mosfet for a near 0 voltage drop protection in single units, at 1000 units its like 14c,

[JA]

Hi Gerald,

Sorry to hear of the bad news. Before you do any repair you need to understand what happened, otherwise the same may occur. The fact that your transformer blew up is curious as well as you said you also need a replacement circuit board for your mount. So to confirm you are saying the mount circuit board is damaged as well as the external power supply too?

For the power supply to blow up it either had an internal fault which caused a catastrophic failure or the load it was connected to (the mount) created the fault condition or there was a connecting cable fault or connector fault. You need to try and zero in on the root cause to eliminate the possibility of reoccurrence.

BTW was the mount supplied from the manufacturer with a power supply and was that the power supply and cabling used? The reason I ask is that a 7.5A power supply seems very generous for the manufacturer to be supplying

Best
JA

[Garnimoa]

Hi JA,
The power supply had a catastrophic failure. Two capacitors blew up making a mess of the electronics in the power supply unit. The mount was turned on and it seemed to suffer with a surge of power.
I am getting the unit repaired and just curious what to do to prevent another failure like this.
I think I will buy a DC battery and power up the scope that way in future.

BTW: The power supply was bought from Jaycar (out of warranty).
I don't have the original power cable anymore as the original owner lost it!!

G

[Rerouter]

would it be these caps that failed ?

https://www.cloudynights.com/uploads/monthly_03_2020/post-326840-0-57430500-1585331136_thumb.jpeg

also any clue as to a realistic current demand for this device? just to narrow down an exact fix

At best guess the device seems to lack any reverse polarity protection, however It is unclear if the failure mode was over-voltage or reverse voltage

My first recommendation would be fit a fuse inline with the power, this will prevent things going poor with what I will suggest next

Reverse polarity case
- Option 1: Fit a P channel mosfet, reverse polarity protection circuit (mosfet, 1 resistor, 1 zener diode) and it will be as safe as houses, as the input is open circuit until it sees about +3V in most cases
- Option 2: Fit a large diode backwards across the power connection wires, any reverse polarity will blow the fuse

Over voltage case
- Recommended: The current regulators fail at 18V, replace the 2x AP1117 series linear voltage regulators with 1x R-785.0-0.5 for the 5V regulator and 1x R-783.3-0.5 for the 3.3V regulator, with this it would take up to 32V to fry the main regulators, some ceramic capacitors may fail before them, but that should not hurt the rest of the device if fused
- Option 1: Fit a TVS protection diode to act like a shunt regulator until the fuse blows if the supply voltage gets too high, e.g. something like a P6KE18A,
- Option 2: I can probably help tweak the reverse protection mosfet circuit to also open circuit the input when the supply voltage gets too high, tell me if you want to explore this option