I've been running several AP7940 and AP7941 PDUs, and recently one of each developed problems with communications. They both stopped responding through the network connections.
On the AP7941, the ethernet link light is occasionally blnking green. I connected to he serial console and found the network settings were correct; they were as I had set them up many years ago. However, in the Advanced... menu, it shows no link. I've tried different cables and ports on my switch, including those used by another working AP7941, and this unit just does not make the link. I suspect the port has some problems. So I can't control this unit remotely, but I seem to be able to go through the serial port and control it.
On the AP7940, the status light is blinking, indicating it does not have a valid IP address. I connect to the serial console and see some strange things. First, the console does not always accept my keystrokes, so I have to repeat characters that I type random numbers of times. Then I see that the IP address is all zeros, so I set it and the netmask and gateway to what they should be. But when I select the "Accept Changes" item, all the numbers I just set go to zero again. The same with anything else I try to set. If I reset the device, the status LED goes red for a long time, and the status display shows "d8". I did not try to control any of the power ports with this, as I'm not sure what it would do. Is the problem with this unit just the network interface, or has something else gone bad in it?
Is it possible to replace just the network interfaces on either of these PDUs?
The AP7940/41 have embedded network cards, which are not replaceable. Would you be able to give me the serial numbers of each unit you're having issues with? And what versions of firmware they are currently running? You can see the firmware revision when you log in serially (which seems to work on both units) - on the main page, it will show an AOS and and APP version, I'm curious on both.
For the issue with the AP7940, "d8" is not an expected result of the LCD display - could it have been "88" instead? The display will show 88 while the unit is booting. Does it stay on 88, or does the display eventually change to show the load in amps? Secondly, has the baud rate of the serial interface been changed, or are you still accessing it with 9600?
On the AP7941, have you tried to reset the unit to default configuration through serial, then reconfigure only IP settings?
Thanks for replying. I got the system information from both units:
AP7940: NMC: v3.3.0, PDU APP: v3.3.1, S/N: BLANK, Model: BLANK, build date: 11/8/2006
I've reset this unit to default, rebooted, and each time I tried to set its IP addresses, they always go back to 0 after logging out (required for the settings to take effect). During the reboot/reset, a red LED shows, and the display shows 88. Then it goes to strange displays, like "d8" yesterday, and what looks like "b8" today. Eventually the display settles down to "Er". I noticed that the key responses become erratic right after the unit is reset or rebooted. Then some time later, the key responses become normal. Can I upgrade its firmware in this state? Would it help with the problems I'm seeing on this unit?
AP7941: NMC: v3.3.4, PDU APP: v3.3.3, S/N: IA0710003962, Model: AP7941, build date: 3/6/2007
On the AP7940, after reset to default and reboot, I'm able to successfully set its IP address, but it still shows "Link down" in the Advanced network menu. This is confirmed by the lack of link light on the ethernet port.
That last paragraph was referring to the AP7941, not the AP7940 as I mis-wrote.
With "Er" on the display of the AP7940, the age of the unit, and the erratic behavior in general - it sounds like there's a power supply fault. You can check the status of the power supply through the serial interface under "1 - Device Manager" --> "2 - Power Supply Status". The power supply on a PDU is not a user-replaceable component.
The AP7941 issue sounds a little less cut and dry. In order to fully apply IP configuration the unit does need to reboot to apply changes. After assigning IP info and logging out, do the NMC LED's go off then back on again? Also, have you tried to do a 1 to 1 direct network between the PDU and a laptop/desktop ot rule out anything network related?
The power supply status on the AP7940 does show FAILED. Since this is essentially a plug strip with switched outlets, I'm curious what makes up the primary power supply.
I did reset the AP7941 before setting its IP addresses, and the LEDs all go through their start-up sequences after I log out to let the new IP settings take effect. But it still shows the same things after its reboot: The Link LED is out, and under network/advanced menu, it shows Link Down. But all the IP parameters are correctly recorded. So it's the ethernet port that's gone bad. And I guess I can't replace just that either.
The power supplies on a switched PDU monitor the current being passed through the PDU, power the display module, and control the outlet relays.
I would agree with the AP7941 - if the link remains down and all the settings are properly enabled, it sounds like a hardware issue. On these older units the display module/network card is embedded and not user-replaceable.
Looks like the current replacement for the AP7940 and AP7941 are AP8940 and AP8941. $1000 for the AP8941, because of a failed ethernet port...ouch!
Thanks again, Matt.
To try to take the sting out of it - the AP8941 is based on our NMC2 hardware, so that model supports v6 firmware and all of the security fixes/interface additions that have been made over the last 5 or so years. This unit also has a removable display module, so if anything does go wrong with the display (or network card), that component can be replaced. There's also a bunch of bells and whistles for the AP8xxx series, like support for temperature probes, USB upgradeable firmware, and the display shows much more information over the older 7 segment displays of the AP7xxx's.
It looks like I got lucky.
Another project had recently retired their AP7940, and I grabbed it to replace mine.
I connected the serial port of my AP7941 to one of our terminal servers, and I can now remotely connect to it through the TS. It's slow, since it's running at 9600 baud, but it works.
thanks again for all your guidance on this.
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