Outboard power for IMB

[Caleb Williams]

And -it might be only my impression- did you have to brake the male, for the female to fit?

The top plastic of the Molex is cracked, it came to us that way, but the connector is not broken. The connector on the GDC side is male. I connected the female power connector from the old DSS200 to the male connector from the power supply and it just worked

[Ryan Gallagher]

The Dolby IMS servers do not have a molex connector on them, only the GDC's, and I'm not sure what all models do. The SR1000's and SX4000's we have on the shelf both do. I just ran a test with an SX4000 that's lost it's identity, and it fully booted running off of the power supply in a re-purposed DSS200, images are attached. For Dolby servers your best option is still the dock, or a projector.

I like the always handy VGA monitor mount ya got. A molex is a winning feature there on those GDCs!... but maybe Dolby didn't want anyone leaving one powered without cooling, plus the BOM cost of the connector on every unit. Edge connectors have almost zero cost (well the male side anyway).

[Marco Giustini]

A Molex socket on the board. So simple. No adaptors. No fuss. Just a random PC or Server!

[Marcel Birgelen]

I understand the allure of building/buying your own PCB to use an adapter, but you'd better be damned confident that the schematics you sent were correct, AND that PCBWay followed them perfectly to manufacture the board for you. A crossed or shorted trace could mean the loss of a server, and that's not a risk I'd be willing to take on a fleet.

I think it's all a matter of perspective.
Only GDC has a molex connector, but did they certify running it this way? It also was a bet if it would work. Putting the wrong voltage on the wrong power bus could also have fried the IMB and nobody is going to pay for your IMB either if your ATX power supply craps out and starts putting 120 Volt on your 12 Volt bus. (And I've experienced server PSUs doing just that, although it was 230V .)
The power supply for the USL adapter is as good as the power supply you provide yourself.

At least, the USL design was built by folks that actually built an IMB themselves. If I have the schematics, I can check if the output on the traces is exactly what it is supposed to be, at least according to those schematics.

I've never checked it, but the Dolby docking station, while it may work with other brand IMBs, is it certified to use it with GDC or Barco makes?

In the end... nothing in life is without risks.

[Hong Sung Hyeok]

Here is it

GDC says not to use them because they may break, but they do work.
The quality and durability of these adapters are generally poor, so you should never connect them to the IMB while the power is on.

[Marco Giustini]

A word of advice on power supplies: only buy good brands from a reputable supplier! The nastiness you will find inside cheap supplies can be very dangerous!

[Phil Ranucci]

Thanks all. The Dolby dock is just too expensive since i'd need 6 or 7. The whole reason for the search is that I can't depend on the staff to turn the power on and off for an hour or so a week. I spoke with GDC and they never made any sort of bench supply for their IMB. I mentioned the molex connector and was told, "yes I've seen that but don't know if it works". The board is labeled 12v on the molex, and the supply Hong posted looks interesting. might give it a try.

[Caleb Williams]

Did GDC make any recommendation for long-term storage of the servers? Again, I'm wondering if they even need to be powered on periodically other than to ̶c̶h̶e̶c̶k̶ ̶t̶h̶e̶ ̶b̶a̶t̶t̶e̶r̶y̶ ̶v̶o̶l̶t̶a̶g̶e̶ check server operation every month or so since the batteries probably aren't rechargeable. Is there something else (like an LD board) in the Barco you're trying to keep alive?

Aside from the fan/power usage, there might be a way to set up some automation to power on and off the projector so you don't need staff to flip switches. Does the model of Barco you have keep the IMB powered regardless of the Barco's state? I'm thinking like the S2 Christie's, you could automate the projector going from standby (IMB off) to powered up (IMB on), then back to standby on a schedule. If you have remote network access that would lend itself to an automated solution even better, assuming the Barco doesn't always power the IMB.

[Marco Giustini]

was told, "yes I've seen that but don't know if it works".

Surely they know or they can find out?
"I don't know" for such an important question can only mean two things
- They can't be bothered
- They DO know but they don't want you to know

Neither of those cases cast a good light on them.

[Ryan Gallagher]

Since 12v barrel type power supplies are a dime a dozen, in fact you might already have some. If one was feeling really cheap and experimental there are adapters to molex.

https://a.co/d/bDKQy5e

Making sure the supply is rated for the load is the trick. Buy one higher rated one and then measure it powered on under load? Use/buy lesser rated once known. This is technically a computer though so one has to account for some inrush current, which a RMS meter won't resolve. So overshoot a bit on the rating unless you have a really fancy power meter or peak/hold features seem to be revealing the inrush.

Or if you have an ATX supply you trust with the molex 12v rail cables... use the pin jumper trick to have it powered on without a motherboard, could probably power several GDC IMBs with just one of them (but they'd all have to be in the same location).

[Marcel Birgelen]

Keep in mind though, an ATX power supply will revert to powered down state if there is an intermittent power failure. It's the battery-powered microcontroller on your mainboard that triggers the "power on" if you have configured that way. Without a mainboard, that signal will not be there.

Also, some more modern ATX power supplies refuse to start at all if there is no motherboard connected.

Another last thing: ATX/AT molex power connectors also include 5V rails. It looks to me like all those hacks power the IMB via 12V only?

[Marco Giustini]

To power on an ATX power supply you just need to short the PowerOn pin (green) to ground (black). A paperclip would do - but you can buy a proper adaptor with a switch on it. That would keep the PSU powered on indefinitely as long as the PowerON signal is shorted to ground - even after a power cut.

Motherboards will usually have a "what to do after a power cut" option which can be set to "Power On" "Last State" or "Power Off" but that is a BIOS option, not a power supply feature.

Unless I missed something, I'm not aware of a PSU requiring a motherboard to power on. It might require a LOAD one one or more rails, but I'm not aware of a special communication between the PSU and the MB.


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[Marcel Birgelen]

You could permanently jump the two "power on" signal wires in the motherboard connector. I've had issues with some fancy ATX PSUs that wouldn't want to properly startup without a motherboard connected to the main motherboard connector. They would power-up shortly, but then quickly power off. I'm not sure if they detected that there was no load on the motherboard pins or if they did so, because there was no communication. Modern PSUs and motherboards DO communicate with each other via internal USB.

Any older/less fancy ATX supply will probably just work fine though.

As for the MOLEX 5V lines: You could potentially cut them to be sure.

[Marco Giustini]

Modern PSUs and motherboards DO communicate with each other via internal USB.

Can you link a model that has this feature? I've never heard of it. Are you sure you're not referring to RGB lighting? That would work via USB.

Edit: Ah cool, some VERY FANCY ones do. So unnecessary!

https://www.corsair.com/uk/en/p/psu/cp-9020259-uk/hx1000i-fully-modular-ultra-low-noise-platinum-atx-1000-watt-pc-power-supply-cp-9020259-uk

[Marcel Birgelen]

We have a bunch of of those Corsair 1000W PSUs around here, don't know their exact make and model, but they all look alike . Most of them are about 2 years old. Some of them I've given away, and I've kept a bunch of them as spare. I've also tried to use one on the bench to power some equipment and it became very clear it won't work without connecting it to a mainboard.

Most if not all of them also have support for RGB lightning I guess, but those are the kind of features I'm not interested in. The motherboard, can, however, monitor and control the fan speed and power stability of the GPU.

We have a bunch of rendering machines with GPUs in them and we upgraded those to dual GPU machines, luckily before the memory prices started to explode. We replaced the PSUs with 1500W ones, not from Corsair, but some other brand which I've forgotten, but they also do communicate with the mainboard.