APC PDU AP7953 - internal flash/EEPROM corruption - loss of model data and MAC ADDRESS

[Thehopefulchurchtech]

Hello, if this is not the right forum section , admins please move.

I have just acquired 3 AP7953 PDU for a church project. having been told there are functional they are not. The internal "factory" setting for Model, Serial number, MAC address when interrogated via the serial port are corrupt. 

I can manually set IP address and ping the units, but that is all the ethernet functionality I can get. 

I can turn on 8 of the 24 ports via the serial, these are the only ones the unit recognises. I suspect because they didnt know what model they are.

Please Please Please -  is there a way of restoring the factory models, serial and MAC address to what otherwise are  working units. If there is not these are going to end up as WEE waste. 

Please can APC/Schneider do the moral thing and provide a process to resurrect these units in a day and age when the environment is key.

The units must have been individually loaded in the factory with these setting post build as the boards appear to be universal across models.

I am happy to sign NDAs stating that information is not to be shared or used for commercial benefit.

thanks in advance for any assistance.

[Teken]

This hardware has been EOL since 2022. As such does not have formal APC technical support.

Its obvious the PDU’s were sold because they are faulty. Your choices are to obtain the last firmware release for this specific PDU and see if it helps restore the equipment or replace the NMC inside.

From personal experience the NMC is physically bad and reflashing the firmware doesn’t resolve the issue.

In the interim if one of the PDU NMC is working swap it over to the other. If the swap resolves the problem you found the issue (Bad NMC).

If however swapping in a working NMC does NOT resolve the issue there are other hardware issues present! ☝️

You may consider submitting a service request to obtain the last firmware release and giving it a try.

Questions Ask . . . 👍 

[Thehopefulchurchtech]

As described above the "hardware" all looks good. The issue i belive can not be solved with a basic firmware refresh. Even if I do this the unit still wont know its MAC address or  model number. 

What I am hoping for is the maintenance / service / factory back door for loading this data. As you say these are EOL so there is no real reason for APC to not release a process. Especaliy if it can only be done via the serial port. i.e. right with the unit. 

[Teken]

All three NMC on the PDU have the same problem?!?

[Thehopefulchurchtech]

Yes all three appear to have corrupt epprom data around model and mac address to varrying degrees two the model amd mac all zeros. The other has a radndom mac address and random characters for the model number.

[Teken]

Do all three allow you to access the internal webpage of the NMC? If so show me the About tab for the hardware. 

What happens when you default the unit to a factory state?!?

[Thehopefulchurchtech]

No.. i cant get to the internal web page. The best I can do is Ping them once I set up manual IP settings. They wont DHCP. 

Fractoy reset defults back to no IP settings.

[Thehopefulchurchtech]

Okay -  I found a fix  to some of the bricked AP7953 which corrupted EPPROMS. The 4 units I have had 2 different versions of the processor board. But they both have a 128Kb I2C EPROM. This contains the unit identity and user settings etc. Without this being right the unit wont boot to be the correct model. On the type where the EPPROM is under the Battery, you can lift the Batter and read and write the chip in stitu using  suitable programmer (I use the CH341a Mini programmer) on the other type where the chip is off on its own it needs to be lifted from the board. 

The following is a read out from a working chip. The section in black shows where the MAC address is stored. I was able to alter to match the serial numbers and mac address of the other units and rewrite their chip and 2 of the dead  unit are now working. I have however got a failed firmware update on one of the others  

Corrupt System info serial readout

Its Corrupt EPPROM read out

working readout

EPPROM Dump for working unit

Amended to fix another unit

This was fairly major surgery... but thought I would post as may help others