Here are some hints prior a repair.
May be it prevents you shipping a well working MAX to RDE and wasting money.
So please, at least read it.
The MAX Passwords are not in NVRAM
but in internal Flash. The procedure to erase the flash and load it again is not trivial and takes between 45 Minutes and 1.5 hours.
MAX 4000 power supplies
If you did already open a MAX 4000, which is not simple, take care near the power supplies. It is really deadly high voltage there. And never run a switched (electronic) power supply without load.
Because we cannot physically look into your dead MAX 4000 remotely, with 98% success the experience says, the +12V line is faulty.
To check the MAX 4000 voltage, connect the black cable of your Multimeter (Voltmeter DC) to any of the black lines comming out of the power supply on the DC side !!!, not on the AC side. - To be shure, look from what side the AC main plug cable comes and !!!! dont !!!! use that side. A detailed view to all connectors of both MAX 4000 power supplies is in our protected service area.
The DC side has many more pins and cables blue and yellow and red. Check all 4 voltages : that must be +5 and -5 and +12 and -12Volt
Never run a power supply without load !
If any of these voltages is gone, the power unit(s) is (are) broken. All MAX 4000 have 24 Volt fans. The 24 volts for the fans are made from +12 and -12 volts. The MAX 6000 has eight 12 Volt fans.
All 2000-4000-6000-3000 Maxes are E1 or T1, not both and its fixed. The TAOS software must reflect the actual WAN E1 or T1 speed.
It is not possible, to convert a 2000/4000 from T1 to E1. We did try it, it takes weeks and very sensible soldering arts.