DSS220 Can't Bootup

[Emmanuel Nwokafor]

We were called today about a Dolby DSS220 shutting down in the during shows see a pic for the behaviour of the server
I contacted dolby technician, he told me this may have something to do with the motherboard power distribution.
I've not come across such a fault before

DSS220 Screen5.mp4

[Marco Giustini]

You either need a new power supply or motherboard. If memory serves the DSS220 starts the PSU (high pitched sound) and then a couple of seconds later the mainboard receives power and the front fans start spinning. The PSU shuts down when the latter should happen. Hence, either the PSU is faulty or the motherboard is.

There is also a chance that something connected to the motherboard is shorted - HDDs, fans, CPU, memory etc.

IF you have permission and IF you know what you're doing, you could

1. Unplug ALL the HDDs and try to power up
2. Unplug all fans and try to power up
3. Unplug everything from MB except CPU and try to power up (motherboard will complain with BIOS BEEPS but that would tell you that it's working)
4. Try the PSU on a different motherboard - the plug should be ATX standard.
5. It says Screen 5, can you try a PSU from another screen? Maybe this should be point 1 as it's very easy to do

BEFORE you attempt any of the above, please be aware that you may lose all the settings and content and OS on the server. So you must be prepared to reinstall the whole thing. As a minimum, you should get an INSTALL copy of the operating system in case you need to reinstall everything. Again, that will wipe the whole storage, including settings.

[Leo Enticknap]

You will have to do this if the OS partition got corrupted.

The Achilles' Heel of a DSS220 is its software RAID. The pro is no RAID card to crap out; the con is that if it just gives you a GRUB bootloader prompt when you power it up, you have to do a clean install of the Show Manager software.

Agreed with Marco that trying a PSU from one of the other screens can't hurt, though every time I've had a bad PSU in a DSS220, no lights have come on at all, anywhere, including the green LED on the back of the power supply module itself. The fact that you do get front panel LEDs suggests to me that it might not be the PSU.

Still, trying one from another house is an obvious first step.

If you do need a replacement power supply module, Dolby will no longer supply them, because the DSS220/cat745 is now an EOL product as far as they are concerned. The good news is that the power supply module is a generic part made by a third party - Ablecom PWS-702A-1R. They are still easily available in the USA, e.g. here, though obviously I couldn't advise on what your options are in Nigeria.

If you do need to reinstall the software, I would suggest emailing cinemasupport [at] dolby.com, and asking them for a link to a "clean install" (not upgrade) ISO of the final version - 4.9.5.2 if your audio processor is not a CP950A, or 4.9.6.4 if it is. You will also need the utility that will burn this ISO to a USB stick such that the DSS220 can boot from it, which Dolby can also give you. The clean install version is not available on dolbycustomer.com - you have to ask them for it - likely because they don't want people accidentally nuking their servers to defaults, all content included.

You might as well install the final version, even if you were previously running an earlier one, because no license is required to upgrade a cat745 IMB.

[Marco Giustini]

Leo, I was thinking that the PSU is ok with no load but when the MB powers up and the CPU starts drawing current, the PSU fails and shuts down. But indeed it could be many things.

[Leo Enticknap]

Point well taken, and I am now seeing the power supply modules on older DSS220s bite the dust on a regular basis. The good news for Emmanuel is that if he is in a 5-plex with DSS220s in more than one house, it won't cost him any time or money to diagnose or rule out a bad power supply as the cause of this fault.

[Pete Naples]

Try changing the MB CMOS battery

[Marcel Birgelen]

Don't think that changing the CMOS battery will solve the problem, although a server of this age should probably get a new CMOS batterry if it wasn't recently changed. A dead CMOS battery will yield you with a BIOS message that CMOS defaults have been loaded and a system incapable of keeping your system time when shut-down, but at the very least you should get something on screen when you connect a display to it.

Is this a single or dual PSU machine? I'm pretty sure this is a simple PSU-related problem. Like indicated before, the PSU probably craps out as soon as the system starts to draw some real power.

[Pete Naples]

I've seen a few lately with this behaviour where changing the CMOS battery brought it back from the dead.
Also Christie TPCs.

[Emmanuel Nwokafor]

The PSU is working, I've tried it on another DSS and it working perfectly. Still can't figure out what might be the cause for not booting up. For me I don't want to replaced the MB at this time. My last experience of such fault the MB was replaced and server started working fine.

[Pete Naples]

Emmanuel,

Try changing the CMOS battery on the MB, seriously.

[Marcel Birgelen]

You can always try to change the CMOS battery, it's just a few bucks at most, but even without the battery installed, it shouldn't behave like this. Maybe if the battery has a short, it could trigger some emergency shutdown from the motherboard side of things, but if changing the PSU doesn't help, then the motherboard becomes the next possible culprit.

I had a Supermicro server once, that suffered a problem with the PSU backplane, the thing both PSUs connect to, so even that's a possible option.

[Leo Enticknap]

Is this a single or dual PSU machine?

It has slots for dual redundant PSUs, but ships with only one installed:

DSS220_rearpanel.JPG
This always seemed to me to be a silly cost-cutting measure. All the previous units in the DSS line shipped with redundant PSUs, and the risk of one failing is known to become significant after around five years (and in other applications for which these modules are used). Add to that the software RAID making recovery from a power failure significantly more difficult, and the combination of only one PSU and no hardware RAID card makes the 220 significantly less reliable than its predecessors, IMHO.

[Marco Giustini]

Interesting point the battery thing.

I agree with those saying a battery shouldn’t cause that behaviour but in the end the MB has the power to shut down the PSU so it won’t cost much to test.

if not the battery, then I’m afraid the next in line is the MB but I would still try unplugging everything from the MB and try to power up.

another unlikely cause could be the PSU backplane.

[Marcel Birgelen]

It has slots for dual redundant PSUs, but ships with only one installed:

DSS220_rearpanel.JPG
This always seemed to me to be a silly cost-cutting measure. All the previous units in the DSS line shipped with redundant PSUs, and the risk of one failing is known to become significant after around five years (and in other applications for which these modules are used). Add to that the software RAID making recovery from a power failure significantly more difficult, and the combination of only one PSU and no hardware RAID card makes the 220 significantly less reliable than its predecessors, IMHO.

In general, I've considered the 220 a downgrade compared to the 200. Why they saved on a < $50 OEM ticket item like the secondary power supply as a default option, or the lack of a hardware RAID card is beyond me, especially if you consider the original list price of those machines.

Same thing when we ordered our CP850, but at least they offered a redundant PSU option. I guess when you design a system from scratch, designing for a redundant PSU may increase system complexity, but those systems are based on off-the-shelf Supermicro designs, which come with easily replaceable PSUs and a redundant PSU backplane by default...

[Steve Guttag]

The argument for single supply is that in a multiplex, you could have 1 or 2 spare supplies for the plex rather than having say 10 of them sitting in servers. Once we discovered that they shipped with just one (the first batch) we started supplying them with two supplies (the second slot and the power distributor is all there).

And I agree on changing the BIOS battery...I've had a low battery do strange things, particularly on boot up. It can really cause grief.