MPU4032 IP KVM Questions: Connection for RS-232 Serial Devices? Fan Replacement? HDMI?

[John T Davis]

Hello, out there!
I'm looking for advice on the Avocent MPU 1U models. The 32-port one: Avocent MPU Digial KVM Switch | IT Management . I picked it up for next to nothing compared to what they usually go for used, but its fans are horrid and sound like they're dying.

Does it take standard 12v 40mm fans? Something else?

Also, I have some network equipment I want to interact with that only has RS-232 console out. Does anyone know where i can get RS-232 CIM modules that work with these? Assuming I can't just use a standard RS-232 cable/Cisco rollover.

Lastly, I have one machine that only talks HDMI. Any suggestions on finding reasonably priced (used?) HDMI/DP CIMs?

Thanks!

 

[gregsachs]

There is a serial module,
MPUIQ-SRL. It needs 5vpower from USB or other source. I haven't used, but aware of.
There is also a HDMI module, HDMI USB Server Interface Module with virtual media, and CAC
but you are probably better off getting a HDMI->VGA adapter and using one of the commodityVGA modules.
No idea on the fan question.

 

[John T Davis]

There is a serial module,
MPUIQ-SRL. It needs 5vpower from USB or other source. I haven't used, but aware of.
There is also a HDMI module, HDMI USB Server Interface Module with virtual media, and CAC
but you are probably better off getting a HDMI->VGA adapter and using one of the commodityVGA modules.
No idea on the fan question.

Thanks! I'm actually feeling a bit stupid right now. I got this thing for $140, so it was still a great deal, but I didn't realize I'd need an adapter to hook up plain RS-232 console-based devices. I have 8 of them. The VGA modules are actually cheaper.

Update on the fans: They're 30mm x 15 mm 5v 3-pin fans.
I ordered some 3-pin 5v Noctuas (40mm x 20 mm) to try to replace them. It's going to be a tight fit.

 

[gregsachs]

You really want a console server, something like an avocent acs8000 or similar I believe, but I don't have experience with those at all. Opengear is also a name I have heard of, but again zero experience. I'd look for a brand like avocent/vertiv with easily available firmware, i suspect that the serial consoles are in even less demand than the mergepoints on secondary market and thus pretty reasonable.

 

[John T Davis]

You really want a console server, something like an avocent acs8000 or similar I believe, but I don't have experience with those at all. Opengear is also a name I have heard of, but again zero experience. I'd look for a brand like avocent/vertiv with easily available firmware, i suspect that the serial consoles are in even less demand than the mergepoints on secondary market and thus pretty reasonable.

I actually have an ACS 6008; it's a great unit. I access the serial consoles on it via SSH'ing into the ACS or, in a pinch, connecting to the ACS by serial.
It's dead silent. I don't think it even has a fan.


I was going to replace that with this unit, but I don't want to have to buy a bunch of expensive RS-232 adapters right now.
I think I'll leave the ACS in place, and use the MPU for devices that don't need a serial port. I have a few of those.

Then I can get one of the serial adapters for the MPU and use that to control the ACS, and use the ACS to control the serial devices I have (switches, mostly). That's probably more cost effective (and less cabling) than trying to get everything on to the MPU.

 

[John T Davis]

Another update on the fan noise.

After getting the top cover off, only one of the fans appears to be bad. The other two are relatively silent when spinning by themselves. They're audible, but not loud.

I should probably try to find a replacement OEM fan, but the ones I've found so far are ridiculously expensive. Like, paid $50 shipped for 3 Noctuas.
It would cost at least $35-$40 shipped to get one OEM fan.

I decided I'd rather have a couple of spares on hand for that much money.

 

[John T Davis]

@gregsachs Thanks again for your help.

Are you familiar with the model names on the Avocent adapters?

• I'm trying to figure out the difference, overall, between SDRIQ, DSAIQ, and MPUIQ cables. I know the MPUIQs are almost certainly meant to be paired with the MergePoint MPUs, but my understanding is that the older cables will work as well, and those are much cheaper online.
• For the VGA option in particular, what would you go for?
  • is the MPUIQ-VMC just as good as the VMCHS? I think the only difference on the latter is that it has USB 3 for the built in virtual media device, which ... does not feel like something worth more than double the price.
  • I'm planning to hook these up to servers that don't have IPMI, so I can access the BIOS and do other things (like system updates) that aren't safe to do over SSH.
• For serial cables, what's the difference between the DSRIQ-SRL and the MPUIQ-SRL? I only need a single serial connection to my ACS6008.

 

[gregsachs]

Apologies if you have seen this already;
Here is the compatability matrix:

https://www.vertiv.com/49fd0e/globalassets/shared/avocent-kvm-adapter-compatibility-matrix.pdf

DSR-* are older units, but still supported, the MPU units are newer.
From the manual,


I believe you are correct that the VMCHS is just the newest USB/VGA module, except for the compact one, the SFIQ-VGA.
I'm definately not an expert on these, just use one at home for a couple boxes with out remote console.
I'm using a couple of the USB-2/VGA and a display port unit

 

[John T Davis]

Apologies if you have seen this already;
Here is the compatability matrix:

https://www.vertiv.com/49fd0e/globalassets/shared/avocent-kvm-adapter-compatibility-matrix.pdf

DSR-* are older units, but still supported, the MPU units are newer.
From the manual,
View attachment 44989

I believe you are correct that the VMCHS is just the newest USB/VGA module, except for the compact one, the SFIQ-VGA.
I'm definately not an expert on these, just use one at home for a couple boxes with out remote console.
I'm using a couple of the USB-2/VGA and a display port unit

Thanks! I saw that chart in the manual, but honestly I got so overwhelmed trying to shop for dongles (I already bought a small horde of HDMI to VGA converters and hope this cabling isn't a nightmare) that I kind of forgot about it.

I kind of hate that chart, though, because I'd like it to tell me what if anything the newer ones actually get me.

That said, I think the MPUIQ-VMC is probably at the affordability sweet spot ($11 on eBay? Or, more generally, about half the price of the VMCHS (which appears from photos to have USB3). And at ~50-60 MB/s (USB2 speed, assuming little overhead), would be like using a stable, but not fast SD card if I had to load media with it.

And that's a big if. I'm in the same room with all this equipment. I can just get up and stick a USB stick in whatever. My main need is for the KVM functionality itself, not the remote media.

 

[Rand__]

Just be warned, older "compatible" models might work but not support all features sometimes.
I used to get the old VGA + PS2 dongles and just map those into USB for keybard/mouse but that stopped working at some point for some servers.
The USB (would need to check if it was DS ones or newer, but def USB2) sometimes didnt do all i wanted.

The serial cables work but expensive (rarely used).

I havent used mine (1016 iirc) in ages due to IPMI but I think they were good value if you find the matching dongles.

 

[John T Davis]

Just be warned, older "compatible" models might work but not support all features sometimes.
I used to get the old VGA + PS2 dongles and just map those into USB for keybard/mouse but that stopped working at some point for some servers.
The USB (would need to check if it was DS ones or newer, but def USB2) sometimes didnt do all i wanted.

The serial cables work but expensive (rarely used).

I havent used mine (1016 iirc) in ages due to IPMI but I think they were good value if you find the matching dongles.

Thanks for the warning about the adapters. I went with the PMUIQ-VMCs. Hopefully they'll work. I actually don't have any devices that do IPMI right now; everything is HDMI/USB or serial. So this is going to be a useful box to pair with my 8 port serial console server.

I got my 32-port (4 virtual screen) model for $136 shipped, and paid about another $100 for the dongles I wanted, which is still a better deal than any of the 8-16 port models I saw used on eBay, and less trouble (and probably cheaper) than trying to build my own with a modern Pi KVM and a splitter.

$45 for replacement fans since one of them was dead and I decided to replace them all instead of having the other two inconveniently die in the future.

But I also had to buy VGA to HDMI converters, so the whole thing ended up around $300. At least I can reuse those forever and ever, right? -_-

Still less expensive than other solutions I looked at, but that wow, I got a deal glow has faded.

 

[Rand__]

I've had mine for 5 years or so,
Avocent (now Vertiv) didm free support (no contract o/c) a couple years back when i was trying to map my Vertiv PSU to the PSU inlet of the MPU, very helpful.

So i think its a good deal and if you use it regularly its well worth the money

 

[gregsachs]

SIde note: For anyone intrigued, I have a 4 port unit listed for sale

 

[John T Davis]

I've had mine for 5 years or so,
Avocent (now Vertiv) didm free support (no contract o/c) a couple years back when i was trying to map my Vertiv PSU to the PSU inlet of the MPU, very helpful.

So i think its a good deal and if you use it regularly its well worth the money

Thanks! That's reassuring. I do plan to use it regularly, and when I think about other ways of accomplishing the same thing, this is still less money, but the initial outlay on cabling caught me off guard. I think I'll feel better about it once it's all set up and working. At the moment, it's a bit of an exploded mess in my office. (Still need to install the new fan.)

Speaking of the fan, I don't suppose you've ever needed to replace one? I'm trying to figure out the pinout on the 3 pin fan header inside to make sure I don't blow up one of my expensive Noctua 5V fans

SIde note: For anyone intrigued, I have a 4 port unit listed for sale

Good luck on the sale! You might also want to try listing on Reddit's HomelabSales subreddit. I've made some sales there.

 

[Rand__]

No, i never thought mine as too loud, but that might have been that its sitting next to a bunch of switches and servers

 

[John T Davis]

No, i never thought mine as too loud, but that might have been that its sitting next to a bunch of switches and servers

I actually think the included fans are pretty good. They're not silent, but they're not loud, either. My other electronics or music playing would be louder. Under other circumstances, I think I'd leave the unit unmodified.

But one of them is dead. It's loud, and grindy, and makes a horrible screeching noise. A 3 pin 5v Noctua 40mm was about half the price of the OEM replacement fan, so I wanted to try that.

I suppose that I'll find out when I try to do the swap.

 

[Rand__]

ah yes that would be annoying. Good luck with that

 

[John T Davis]

ah yes that would be annoying. Good luck with that

Well, that didn't work. I didn't break anything, but the Noctua 5v 3-pin is not a drop in replacement. It didn't spin at all, and the device gave me a "fan missing or stuck" error. So, I guess I get to learn how to use my multimeter.

(I found what looks like the OEM fans on Newegg, but I really don't want to wait 2 weeks for them to get shipped from China since I've already got 3 otherwise usable fans here. ... I'm sure I'll end up caving and just ordering the OEM ones at some point.)

 

[Rand__]

If your lucky the just swapped some pins

 

[John T Davis]

If your lucky the just swapped some pins

Seems to be the case. I'm constrained by not really understanding how to use my multimeter yet.
I managed to find the ground pin with a continuity test to a grounded part of the chassis. It does that much in AUTO mode, at least.

I found a video review of my multimeter and figured out how to measure voltage.

I've got continuity to ground on the center pin on the board's fan header. That diverges from the Noctua spec.

So it looks like this, when staring straight on at the fan connector on the board:
Board: 5v || GND || Tach (RPM)
Noctua: Tach (RPM) || 5v || GND

I have some 10 cm breadboard connectors I use for motherboard headers. It's sloppy, but I wired up the Noctua correctly, and it works great.
I need to secure the breadbin connectors to the Noctua connector. Do you think imitation Kapton tape would be enough for that? I don't need it to be the best glue ever; I just need it to not wiggle itself free.

Reference for Noctua (3 pin, 5V):

What pin configuration do Noctua fans use?

Can Noctua fans be used with only + and GND connected? All Noctua fans can also be used when only + and GND are connected. The fan will then run at full speed. Please note that modifications to our fans such as cutting the cables of a fan can ...

faqs.noctua.at