Film-Tech Forum ARCHIVE: Datasat AP20 failure

This is topic Datasat AP20 failure in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=16;t=002242

Posted by Peter Castle (Member # 1997) on 03-12-2015, 02:15 AM:

Last June we decided to move from a CP500 (fed by a USL D/A) to a new sound processor. Looking around at the available units we decided on a Datasat AP20, only to find they were almost non-existent in Australia. But we went ahead, and have had no problems - until last night.

The unit decided to stop working - prior to our audience entering for the night's show (we only run once or twice a week). A pre-show test worked fine several hours before but, when preparing for the show, I discovered that there was nothing operating on the AP20, apart from the blue power light on the front.

Has anybody had this happen? Because we are the only unit our installer has handled, there are no spare parts. Datasat think it is the power supply and will ship one in. But what if that is not the problem? We have five days until the next show, so time is not entirely of the essence (unless a new power supply is not all we need). BTW, I tired cycling the power, holding the power button down, ... to no avail.

It is sad that there are so many pinch points in digital cinema that can cause a screening to be called off. This is probably the cheapest component. What do you think about us purchasing a backup unit, in case this happens again.
(We still have our CP500 and the other gear, but all our cables and plugs are now different.)

Posted by Carsten Kurz (Member # 5396) on 03-12-2015, 07:01 AM:

PowerSupply fail is rather typical. We have our AP20 for two years now and no issues so far, but as with other CPs, power supplies do fail, and I know about two failed AP20 supplies from another cinema forum.

Do you use the internal crossover function of the AP20?

We designed a simple fallback for your system that cost us just 30US$ plus some soldering - a few cheap S/P-DIF DACs from ebay. We can feed digital audio from the server directly to the amps using this simple setup. Input/output connectors are DB25 to match exactly the connectors going to/from the AP20, so we can pull the AP20 out, connect the converters in.

That approach, however, doesn't work if you used the crossover function in the AP20.

If you also used the CP500 crossovers, you may indeed try to hook this up again. Five days should be enough to find a cable solution that still allows to get the AP20 back in.

- Carsten

Posted by Peter Castle (Member # 1997) on 03-12-2015, 07:57 AM:

We unfortunately are using the crossovers in the AP20. I'd forgotten that part of our conversion entirely. When we stopped using the CP500, we also stopped using our THX crossovers. So that's just another difficulty in having a backup plan.
The idea of having a second AP20 is also a problem. The Australian dollar was worth $US0.93 when we bought our AP20 last year. Now it is worth $US0.76. This is having a great impact on investment in cinema in Australia.

Let's hope it is just the power supply.

Posted by Leo Enticknap (Member # 534) on 03-12-2015, 11:17 AM:

Given that you have the blue light on the on button (which I would expect you not to have if the PSU is NFG), could it be simply that the touchscreen/display panel is buggered, and that if you VNC-ed into it from a PC on the same network, you could control it and it would work OK? The AP20 does have a built-in VNC server, though you have to dig deep into the manual to learn of this fact.

And presumably if you only bought the AP20 last summer, the unit should still be under warranty? Although obviously there would be significant down time while the required part is imported, as you note.

Our backup plan is, in a nutshell, another AP20. In our AP20 theater we have two screens, both of which have AP20s. Thankfully, one of the screens is only in use regularly for one day a week (though more often during festivals and the occasional private rental screening). If one of them suddenly and catastrophically failed, we'd transplant the other temporarily and reload the saved settings thru a USB stick. The smaller screen also has a backup CP650 that could be reinstated if needed.

And yes, agreed about the strength of the USD. Some relatives visited from England recently and were complaining about that loudly and often!

Posted by Peter Hall (Member # 695) on 03-12-2015, 01:54 PM:

HI Carsten
SPDIF or AES ? I would be keen to find AES converters at that price...

Posted by Carsten Kurz (Member # 5396) on 03-12-2015, 03:24 PM:

Peter - in our case, S/P-DIF worked. In general, they have no problem to decode AES, as the differences are small. S/P-DIF is single-ended, while AES usually is symmetrical, but it's no big deal to interface one to the other. Our Sony actually has two separate Audio outputs, one AES, one single-ended, they work in parallel.

If you have an old Doremi AUD-D2A or a Dolby DMA8/+, or, as Peter, a USL D/A, of course they are the better choice. Used AUD-D2A sometimes go for as little as 50-80US$.

But the crossover thing is a problem. Our plugin solution is in place in a few minutes, as we don't use the crossover function of the AP20.

If you have to setup cables and crossovers again from scratch, that could take a lot longer. I have never dealt with the THX crossovers - do you still have them on site? Is it possible to feed them directly from the DACs? Even with only a suboptimal adjustment, it can still save a show.

The AP20 power supply is an OEM part and available from other sources as well. That doesn't mean it is easier or faster to get from these sources, but it may be worth a try.

http://www.powdec.com/pdf/hdt125.pdf

- Carsten

Posted by Marco Giustini (Member # 4544) on 03-12-2015, 04:39 PM:

there are so many things that can fail on a D-Cinema setup. If you go on that route, I cannot see why you should have a backup sound processor and not a backup server or a backup ICP - which of course it is not feasible.

AP20's PSU's appear to be a little fragile. Not a huge problem at the time being but the only component that fails so far.
I am not an electronic engineer but I would think that a PSU is a basic component, easy to get it right?

Posted by Leo Enticknap (Member # 534) on 03-12-2015, 07:18 PM:

quote: Marco Giustini
there are so many things that can fail on a D-Cinema setup. If you go on that route, I cannot see why you should have a backup sound processor and not a backup server or a backup ICP - which of course it is not feasible.

True, but it is feasible to keep spares in stock of parts that are either designed for a limited life or are known to be prone to premature failure (one example of the latter would be the shutter gearbox in the Vic 5), especially if the part in question isn't very expensive. If having a $50 power supply unit in your cupboard could mean the difference between a lost show and saving it, and especially if there is significant anecdotal evidence that those PSUs tend to crap out, I'd say it's worth buying.

But granted, you can take contingency planning to pointless extremes, at which the cost of insuring against a problem happening is higher than that of dealing with it if it does happen.

Posted by Ray Derrick (Member # 1001) on 03-12-2015, 07:28 PM:

Hi Carsten

There are 17 different models for the HDT-125. Do you know which one is used in the AP20? I am assuming it is the HDT125-33 which has voltage rails matching the test points in the processor, but of course, one would be foolish to rely only upon assumption.

Posted by Carsten Kurz (Member # 5396) on 03-12-2015, 09:49 PM:

As far as I know, it's the -43 type.
Powersupplies do fail. The old analog Dolby and USL processors had backup supply connectors for a reason. CP750 also has it's fair share of power supply issues.

Does it make sense to stock your own power supply spare? I don't think the AP20 is exceptionally prone to power supply failures.

I'd go for a full CP spare solution - either the basic D/A hookup, or the previous CP500/THX crossover solution.

- Carsten

Posted by Peter Castle (Member # 1997) on 03-17-2015, 05:26 AM:

AS all suspected, it was the power supply. Datasat supplied one shipped from US to Australia in four days, as no spares in Australia. So back in operation, ready for tomorrow's show.

As for a backup, has anyone an idea of the incremental cost of the AP24 that Datasat has produced to handle Auro sound, with 24 channels as opposed to 16 in the AP20? There's little on Datasat's webpage, and on Barco's it is tagged with a Barco logo.

Posted by Carsten Kurz (Member # 5396) on 03-17-2015, 06:18 AM:

I would assume this can only be obtained as part of a full AURO 3D deal?

- Carsten

Posted by Ray Derrick (Member # 1001) on 03-17-2015, 04:52 PM:

The failure turned out to be caused by a dead +15V rail in the power supply. Datasat were very helpful and prompt in sending out a spare PSU.

Posted by System Notices (Member # 2357) on 01-23-2017, 12:22 AM:

It has been 677 days since the last post.

Posted by Leo Enticknap (Member # 534) on 01-23-2017, 12:22 AM:

The same thing happened to me this afternoon. The AP20 was totally and utterly dead. I checked that it wasn't the fuse in the back of the unit or no power supply going into it. In my case, not even the blue button or the two LEDs below the Ethernet jack lit up when power was applied. And it was very sudden, too: a co-worker who used it last night reported that it worked without any hint of a problem, but when I came to power it up about 12 hours later ... nothing.

I didn't have time to investigate further, as by that point I was in a race against time to connect and configure our backup CP650, and get the show up. The unit is going back to Datasat tomorrow (thankfully they're only a few miles from the theater) for repair, and hopefully the dying PSU did not take any other components to the grave with it.

This AP20 was installed new and first used in September 2014, and so its power supply has lasted about a year longer than Peter's did. Given that we also have AP20s in our two other houses (much bigger, and the loss of a show in either due to equipment failure would be a far more major issue), if the cause of this failure is confirmed as being the PSU croaking, I'm going to suggest to my boss that we replace the PSUs in our other two AP20s preemptively and then keep a spare in stock.

Posted by Carsten Kurz (Member # 5396) on 01-23-2017, 11:50 AM:

Our's is three and a half year old now, but only running for about 3hrs a day, then switched off completely (power cut). But I guess I will try to dig up an OEM PS for it as well soon.

- Carsten

Posted by Scott Norwood (Member # 30) on 01-23-2017, 01:46 PM:

Since these are basically computers, do they not use regular ATX power supplies? (I have not opened one. I don't know.)

Posted by Leo Enticknap (Member # 534) on 01-23-2017, 04:57 PM:

I think that's essentially what they are, but with a single multi-pin connector to the backplane, and that's it. This connector isn't like the regular ones that go to the motherboard, molex or SATA power supplies.

They probably are an off-the-shelf item from somewhere (just like you can stick regular Supermicro server slide-in PSUs into a DSS200, which, because of the double redundancy, I have), but as these machines are so mission critical to everything we do and there is no double redundancy in the AP20 power supply, I'm not interested in saving a few bucks to avoid buying Datasat official ones. $200 extra is nothing if it guarantees not losing a show and having to give refunds to 615 customers.

Yesterday was a lucky escape: the AP20 that croaked was in our smallest house (78 seats), and the show was 16mm (projector has integrated preamp, so line level comes out of it), which made it relatively easy to jerry rig our standby CP650 into the system and salvage the show. But if this had been a DCP screening in our 615-seat house with VIPs in attendance ... ouch.

The AP20 is a great processor and almost perfectly suited to the sort of programming we do (multiple formats, multiple sources, all the time), but the power supply unit does appear to be its Achilles' heel.

Posted by Carsten Kurz (Member # 5396) on 01-23-2017, 06:08 PM:

They are +/-5V and +/-15V supplies. Common supplies are +/-5V and +/-12V.

Yes, you can try to source one on the internet, but the original one that fits the available space seems to be only available on special order in quantities.

Best is to order a spare from Datasat.

- Carsten