Apex "classic" Eb8 with unlit status LED

[Nomadic1]

I have an old EB8 that does not work. Powering it up will immediately activate the two relay based outlets, but there is no other sign of life. The status LED does not light (I have tested it via my DMM's diode test to make sure the LED is good) at all. I've disassembled it completely and have been checking the low voltage side of the board. The MCU is receiving 5V at its VCC pin, as are various other test points on the board. I'm not reading any shorts anywhere. There's been no salt ingress, and no corrosion is present, even on the Aquabus ports. Diodes pass testing, the bridge rectifier is working properly as well when it is powered on. Is it possible that the ATMEGA88 MCU is bad here? If it is, does that render this EB8 unrepairable (due to not having files to reprogram it available to the public)?

 

[braaap]

I have an old EB8 that does not work. Powering it up will immediately activate the two relay based outlets, but there is no other sign of life. The status LED does not light (I have tested it via my DMM's diode test to make sure the LED is good) at all. I've disassembled it completely and have been checking the low voltage side of the board. The MCU is receiving 5V at its VCC pin, as are various other test points on the board. I'm not reading any shorts anywhere. There's been no salt ingress, and no corrosion is present, even on the Aquabus ports. Diodes pass testing, the bridge rectifier is working properly as well when it is powered on. Is it possible that the ATMEGA88 MCU is bad here? If it is, does that render this EB8 unrepairable (due to not having files to reprogram it available to the public)?

Have you tried a different USB cord? I know it seems like the simple thing but multiple times I had a USB cord not work with my apex. Including with the classics and the 2016 versions.

If you have tried multiple of them then it could be the microcontroller. I feel like I saw a thread about it on RC one time. But considering you can get an EB8 for like $50-80 on here or ebay I wouldn't spend too much time on it. https://www.ebay.com/itm/2860521759...gea9rWPhAGVOITtb3c=|tkp:Bk9SR9aLi-69ZA&edge=0

 

[_AV]

The LED is powered directly by the MCU. If you get power to the MCU, but no LED, either the MCU is bad or the firmware in it is corrupt. Either way, it's a toast without firmware.

 

[Nomadic1]

Have you tried a different USB cord? I know it seems like the simple thing but multiple times I had a USB cord not work with my apex. Including with the classics and the 2016 versions.

If you have tried multiple of them then it could be the microcontroller. I feel like I saw a thread about it on RC one time. But considering you can get an EB8 for like $50-80 on here or ebay I wouldn't spend too much time on it. https://www.ebay.com/itm/286052175902?_skw=Neptune+EB8&itmmeta=01J7QE2RQ1V3ND9P2RT30ZC51M&hash=item429a09d01e:g:Jr8AAOSw5Yhm3nNE&itmprp=enc:AQAJAAAA0HoV3kP08IDx+KZ9MfhVJKkXJrL63DpoAd7iqhm9XE3ilFg5kgLz0hp80s6kCb2WBp3UInteoy3oVb72ejG1gY/JU201FsS2PQWhvzWznnw3Tlv38alOnedCCRQRoU/rO/4pKJC4wclihX+1TKNaqZTwXy/qnm5qZXZRXr7VJHMV8Zrtya2nxtPv7x+V0Ffr5+xmrSFvrsAoC8Xwp/ncs1LDtHiAUpt8hAXafh1vB8lkUmxJQcY3w1+dAcXEO7ZRbJV/fgea9rWPhAGVOITtb3c=|tkp:Bk9SR9aLi-69ZA&edge=0

Thank you, but the status LED should come on even without anything plugged into the AquaBus, so I don't think using a different cable would apply here.

 

[Nomadic1]

The LED is powered directly by the MCU. If you get power to the MCU, but no LED, either the MCU is bad or the firmware in it is corrupt. Either way, it's a toast without firmware.

Ugh, that's what I thought. I traced back the LED to the MCU and thought that can't be good that there's no activity. Thanks for preventing me from going down the rabbit hole and wasting a lot of time :)