URSA MINI SEMI-PRO 4.6K???

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robert Hart

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URSA MINI SEMI-PRO 4.6K???

PostWed Dec 23, 2020 7:17 pm

Here is the conundrum. I have been mustering broken URSA MINIs with a view to eventually combining enough bits to make up a complete camera. One is an URSA MINI 4.6K which presented with a substantially damaged upper case with the top broken out.

The described history was that it had functioned after its accident but had since succumbed. In the course of its journey, something must have jolted into place. It was fully working when I decided to power it up to see what was left of it that worked. I was mainly after the SSD recorder it was wearing.

I was minded then to move its inner workings across to a Mini Pro core frame which is identical. The Mini Pro itself was dead. On taking apart the URSA MINI I find that the front piece which supports the sensor PCB and the lens mount is also substantially damaged with small pieces falling away.

The lens mount itself was loose but it may have been left that way following exploratory visitations. With this part having to support the weight of lenses, sticking together the many pieces of broken magnesium alloy castwork with JB weld won't cut the mustard.

It must have had a very substantial accident, like left on a car roof and fallen off type of accident or crashcam maybe.

I had hoped to transfer this entire front piece because the seal of the sensor and IR filter would not be disrupted by the move. It would also match the left side cover and monitor. However it is also fractured. So the sensor board itself has to migrate to the good URSA MINI PRO front. This is where it gets complicated.

The URSA MINI PRO front also contains a ND filter wheel assembly. The URSA MINI PRO left side cover and swing-out monitor is completely different with more electronic bits and pieces attached. The URSA MINI left case and its screen will bolt up to the URSA MINI PRO core frame but the added filter wheel assembly takes up more space and fouls the side cover.

The display screen connection appears to be the same however the touch controller may be routed differently. The ND wheel would be nice to have operating but the rest of the functions will be just ornaments in the side cover.

There is a lot of dust inside the URSA MINI 4.6K. It looks like it has faithfully earned its keep. The URSA MINI PRO case was clean inside but caved in at the right side cover with the main PCB having been sprung in at least 5mm inwards and then rebounded back. It seems unharmed to the eye but that smack in the gizzard was near the main processor with all its many little solder joints begging to fail.

I shall have to have a good think about this or pack all the loose pieces in a box and wait for some more busted URSA MINI 4.6K cams to come along in the fullness of time.
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Ellory Yu

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Re: URSA MINI SEMI-PRO 4.6K???

PostWed Dec 23, 2020 7:55 pm

Unless this is a hobbyist playing around or to learn, why not just buy a working UMP?
URSA Mini Pro 4.6K G2, Blackmagic Design Pocket Cinema Camera 6K, Panasonic GH5
PC Workstation Core I7 64Gb, 2 x AMD R9 390X 8Gb, Blackmagic Design DeckLink 4K Mini Monitor, Windows 10 Pro 64-bit, Resolve Studio 18, BM Micro Panel & Speed Editor
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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostWed Dec 23, 2020 8:11 pm

Ellory.


There is a bit of both going on. Being a bit low on the funds is also a factor. I have been lucky enough to patch cameras up in the past, Sony, JVC, and Sony TCD audio recorder. When they have been physically damaged there is most times a line of cause to follow. Mysteriously dead electronics are another matter. I also hit lucky with the "big" URSA when it went down after a sensor was replaced. It also had an intermittent power thing going on. That turned out to be fixable with a bit of solder on the Molex plug pins. There is a lot of waste when things get the chuckout. Mostly they are gone for good but some can be recovered. Now if only I could jump into BM's dumpster for half an hour. If anyone has an Ursa Mini Pro well out of warranty support with the magenta screen of death, the sensor assembly on this one may be good although the mainboard is toast.
Last edited by robert Hart on Wed Dec 23, 2020 8:15 pm, edited 1 time in total.
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rick.lang

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Re: URSA MINI SEMI-PRO 4.6K???

PostWed Dec 23, 2020 8:12 pm

Why climb a mountain? Because it’s there. I’m enjoying hearing about Robert’s adventure.
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Ellory Yu

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Re: URSA MINI SEMI-PRO 4.6K???

PostThu Dec 24, 2020 4:30 am

robert Hart wrote:Ellory.


There is a bit of both going on. Being a bit low on the funds is also a factor. I have been lucky enough to patch cameras up in the past, Sony, JVC, and Sony TCD audio recorder. When they have been physically damaged there is most times a line of cause to follow. Mysteriously dead electronics are another matter. I also hit lucky with the "big" URSA when it went down after a sensor was replaced. It also had an intermittent power thing going on. That turned out to be fixable with a bit of solder on the Molex plug pins. There is a lot of waste when things get the chuckout. Mostly they are gone for good but some can be recovered. Now if only I could jump into BM's dumpster for half an hour. If anyone has an Ursa Mini Pro well out of warranty support with the magenta screen of death, the sensor assembly on this one may be good although the mainboard is toast.


Robert, Don't get me wrong, I'm all for recycling, salvaging, restoring in the name of learning and the fun of bring dead things back to life. So more power to you! I stand beside Rick and read about your BMD adventure as they come along. :D
URSA Mini Pro 4.6K G2, Blackmagic Design Pocket Cinema Camera 6K, Panasonic GH5
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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostThu Dec 24, 2020 2:56 pm

One postscript to the odyssey is that with the URSA MINI 4.6K front lens mount support was fractured along with the microphone supports. That leaves only the the URSA MINI PRO front lens mount support with its ND filter wheel available to use.

That will not fit inside of the left side cover of the URSA MINI 4.6K. In the course of investigating, I also discovered the sidescreen must have taken some of the hit. It is fully functional but the hinge is not quite what it once was, with a few cracks and a ruptured look about it.

After all that apparent violence, it is a minor miracle that it continued to operate.

The front sensor board of the URSA MINI PRO and the front lens mount support are cleverly donkeytrapped with an extra locator pin. The older sensor board cannot be mistakenly mounted to the newer front lens mount support.

For now, the bits and pieces have to remain asleep until another donor cam comes along with an intact frame.

The URSA MINI PRO seems to have a lot in common in its core with the older camera but it is much more feature loaded with the left side cover being much more complex. Goodness knows what the innards of the 12K look like. It is probably very cosy and tight in there.
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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostThu Dec 24, 2020 7:27 pm

The further postscript is that impatience has won out. I had some JB Weld I bought in a while back.

The front lens mount support is attached by four screws which pass through tabs cast outward at the corners. The upper two tabs had cracked off along with the nearby in-camera microphone attachment points.

The front of the camera had been firm when I tested it. While the tabs had cracked off, the cracks were irregular in shape and surface texture. The assembly had remained gripped together until I took out the fasteners then the tabs fell off.

For the time being I have reattached the front lens support to the core frame by the lower two screws, attached the two tabs with the two upper screws after I laid a bead of JB Weld in the breaks.

To firm the assembly, I added a small web of JB Weld across to the frame on each side in positions where it can be conveniently cut later for the entire piece to be replaced.

URSAS BUSTED 2.jpg
URSAS BUSTED 2.jpg (99.72 KiB) Viewed 3911 times


The takeaway lesson is that the structure of the assembled casework is well fit for purpose It has been artfully designed so that there is no unnecessary bulk, unlike the big URSA which will make a weightlifter of you.

In a fall, the big URSA which would probably just chip some paint, crack a screen or crunch a hole through whatever it hits or fracture your ankle and foot bones. The Mini casework will be unlikely to suffer falls with a heavy lens attached, a top handle attached directly to the upper case, a side handle attached to the right side cover without experiencing structural damage.

The trend for folk to add cheeseplate cages around their cameras as a turtleshell may have merit. The camera body can be supported top and bottom. Concentrated stress points by top and side handles are taken by the cage and distributed to multiple points on the camera body.

All the very best for your Christmas and New Year folks and hopefully you are not forced to dance with Rona before you can receive your shots.
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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostFri Dec 25, 2020 5:28 pm

The final chapter. Very early this morning before the glow in the East started, I copped a dose of allergy and a spider bite. There was not going to be much useful sleeping so I got up and put the camera back together using the best pieces of the two wrecks.

The JB weld glue patches on the front lens support frame are surprisingly strong. Until another front end comes along, it will suffice but obviously no heavy 500mm lenses are going on the front.

The impact must have seriously loosened some connections. The original damaged frame rocks on the bench on the opposing corners so it is quite out of shape. This may have pulled some plugs out of proper connection. It was reported as having no sound from external mics. So far as I can see everything works as it should, with and without phantom power.

The side screen is delicate with a crack in the case below the buttons. The plastic trims at the hinge were fractured but the hinge and pivot remain intact.

URSAS BUSTED 3.jpg
URSAS BUSTED 3.jpg (86.59 KiB) Viewed 3859 times


It would have been cool to have used the left side panel from the wrecked Mini Pro but there is too much hardware which is different and too much extra wiring with nowhere to go.

One thing I do not know about and that is how hot the body should become. This one gets quite warm on the right upper side and upper right vent. That is logical because that is where the Xilinx processor is and they get really hot. The heat pipes run up inside the right to the heat exchanger which runs across the top under the mesh vent. It may be normal behaviour. Any advice will be appreciated.

So in a sense it was my Christmas present to myself by 7-30am in the morning.
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Overlander

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Re: URSA MINI SEMI-PRO 4.6K???

PostFri Dec 25, 2020 5:35 pm

Fascinating fix! Particularly Xmas morning. Good old JB Weld. I once fixed a round baler drive wheel with JB just to get use through the next field. Years later is was still chugging along.
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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostFri Dec 25, 2020 5:46 pm

Two-part resins seem to have come a long way. At first I thought the material had gone stale in the shop because it did not do much after being pasted into and across the joints. It had hardened overnight.

As for the cameras, there is an order in which things should be dismantled and some things which do not have to be unfastened.

I am not confident the mainboards are a candidate for solder reflowing if they have gone dead after some violence. Whilst roasting joints on one face of the 4 layer PCB, there are parts on the opposite face which are going to fall off.

From a business POV it is certainly not worth the labour cost for a maybe-maybe not outcome and possible failure in the near future.
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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostSat Dec 26, 2020 1:11 pm

I took the combined camera to the local sportsground for a quick test. Definitely ND filtering is a must. I was forced to a fast shutter and f16/f22 aperture which introduces diffraction. There are bound to be some dandruff flakes or dust motes on the sensor somewhere.

I just haven't found them yet in the image. I filtered the air as best I could with an evaporative airconditioner running, reasoning that as it filters out stuff which provokes my allergy, it might take out some environmental dust as well.

The camera is a different beast to the "big" URSA but a lot easier to handhold. With a proper grip handle it would be easier. Handcradling was a bit of a mission with my arthritic wrist.
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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostSun Dec 27, 2020 4:08 pm

For sake of curiosity, I had another look at the mainboard of the donor dead Mini Pro which I drew from to repair the URSA Mini 4.6K. Things look intact but when I gently warp the board slightly, it creaks, very faintly.

This hints that maybe some of the Xilinx processor solder joints onto the main board have disbonded or the entire board has begun to delaminate. The kick in the guts it got from a fall on the sidehandle would have certainly shaken it up. The conundrum is how does one resolder the processor onto the mainboard without all the parts on the reverse face of the board falling off?

The short answer probably is "you don't". The longer answer might be "very carefully". Apparently surface-mounted electronic parts which are attached by the solder reflow process are good for one shot at original assembly. I have some reading to do.

I had been very tempted to test the Mini Pro sensor board by connecting with the mainboard off the URSA Mini 4.6K I do know to be good. However I thought better of it, there being no point in taking the risk of bricking the good mainboard. There are times when one should not be too greedy. This has been one of them.
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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostSun May 09, 2021 5:22 pm

Well, it seems that the broken and fixed URSA Mini 4.6K may yet live on. It has about 12 hours up after yesterday after being second camera, filming an event.

What do you do when some housebreaking thieving sod has thugged your 200mm Nikon f2.8? Put a doubler on the back of a vintage Sigmatel-for-Nikon 135mm f1.8. It did the job. Why the lens prop? I was fretful about too much stress on the JB Weld-ed internal magnesium framework.
URSA PATCHED.jpg
URSA PATCHED.jpg (27.02 KiB) Viewed 3348 times


Now that I have discovered that I can change settings on the main screen without having to race around injuring my claws inside menus, things have improved. It is not a bad camera, still down a bit on gain compared to the Sonys I have played with but not bad at all.

I am still eyes-open for a physically distressed URSA Mini Pro as I have most of the casework and attachments. However the only specimens which appear seem to be the "died-with-blackscreen" examples at extortionate asking prices offered as "for parts-only.

Some folk are buying them at the asking prices. I suspect there is a bit of buyer's remorse going on.
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rick.lang

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Re: URSA MINI SEMI-PRO 4.6K???

PostSun May 09, 2021 7:26 pm

Congratulations Roger on the success of your adventure to resurrect the URSA Mini 4.6K. Good to see you were rewarded.
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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostSat Oct 30, 2021 7:21 pm

After a winter sleep, the patched up Ursa Mini 4.6K still lives. It had about three hours of continuous duty at an annual fly-in and did not lay down.

The image has not been graded. It is as came out of the camera, recorded as ProRes.

My tripod head's pan drag had failed so I had to sit back from subject further than I usually do to stay on it.

The zoom is a Sigma 50-500 f4-f63 which has seen better days. It had been previously dropped, had fungus in it and it does not hold focus through the zoom movement for reason the little plastic followers which engage in the cam slots are worn and damaged.

One lives within one's means.

For audio, I had a Sony directional mike inside a Rode muff into Ch1 and an old Uniden VHF scanner into Ch2 for radio.

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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostThu Dec 30, 2021 7:56 pm

A postscript to the broken camera story. The Ursa Mini 4.6K is still running fine. The damaged Ursa Mini Pro G1 mainboard is not so well. I thought I would have a shot at reflowing the processor which seemed to have become partially disconnected by the the fall that broken parts donor camera had taken. I should have stayed in bed.

The nice kit I bought in went "VVVt-t-t-t" the moment I turned it on. Well past sendback time so that's that. So I did a silly thing and was using another heat gun which is temp controlled. That was well and good but that played up too. Can't win a trick buying product these days. Then I found after the event that the digital temperature thermometer was not working either. It topped out at 120 degrees C although it is supposed to measure higher.

So with the head gun coming and going and the processor not making temperature according to my digital thermometer, there also occurred a small problem with the heat shield I made lifting up in a corner that I did not spot. There was hotter air than needed leaking under. I was just about to give it all a rest when there was the sound of a .22 bullet going off in a fire.

An inductor had copped a little too much heat and burst, blowing several of the microminiature components off the main board, to where the good Lord alone knows. I combed one out of my hair later. It turns out that everything had got hot enough to melt the solder. The heart shield had gone flying.

If that little explosion had not happened, there was a chance that the processor had become successfully re-attached as it no longer creaks when you press upon it. With all those other tiny parts gone MIA, that game is now done and dusted. It was worth a shot as nothing was really lost. It is also a salutary lesson on why BM does not do board level repairs.
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rick.lang

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Re: URSA MINI SEMI-PRO 4.6K???

PostThu Dec 30, 2021 8:46 pm

robert Hart wrote:… The heart shield had gone flying...


I believe your heart shield is doing its job.
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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostFri Dec 31, 2021 8:19 am

Rick Lang.

That was a typo. It should have read "heat" shield but I will leave it there. It's more entertaining.

Mainboards which have gone stone dead after a tripod fall onto the sidehandle may be repairable by reflowing the solder joints in the area where the three screws securing the heatsink are. Judging by the witness marks on the heatsinks of a few specimens, there has to be up to 2mm of movement of the heatsink radiators.

Much less of that will be bending in the mainboard itself directly under the main processor which is a very stiff piece with a wide span of about 30mm. The mainboard is not preloaded before the soldering is done so there is already tension across the soldered joints from the screws fastening the heatsink against the processor. The extra tension from a jolt could be the last straw.

On a couple I have seen, there appears to have been no mechanical contact between the fractured sidecover and the mainboard.

There is no practical design solution. The mainboard has to be mounted as it is and the heatsink as it is. The BM mainboard is not unique with this potential problem, There was a generation of PC mainboards which used clamps in tension to fix the processor into its socket. Guess where the mechanical support for the processor, its heavy heatsink and attached fan came from, the mainboard.

Because of the need for unimpeded cooling, encapsulation of the whole mainboard assembly between two sturdy supports like automotive ignition systems is not practical. The encapsulation material used in General Motors automotive ignition systems did not play too well with heat and turned into conductive jello.

The original "big" Ursa came pretty close to ideal with its solid spine which the mainboard and two processors fastened to with the processors thermally tied to that spine with conductive pads. I don't know how good pads are compared with much thinner paths through thermal paste.

A spine could be cast into the Mini Pro family casework with the heatsink and existing mainboard commonly fastened to it through the existing attachment holes. In the present layout, there could be difficulties in assembly and added costs.

How far do you go before you end up with a camera which weighs like a house brick?
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Uli Plank

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Re: URSA MINI SEMI-PRO 4.6K???

PostSat Jan 01, 2022 1:08 pm

Well, the original Arri was constructed to be used in war zones and is said to have sometimes survived the cameraman (in this case all men, no gender issue here).
The original Alexa is also quite a lump of metal and some second-hand offers look like they experienced a similar fate.
But I think there are a lot of other cameras, analog or digital, which would suffer substantial damage when falling on their side.
No, an iGPU is not enough, and you can't use HEVC 10 bit 4:2:2 in the free version.

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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostSun Jan 02, 2022 5:53 am

Uli Plank.

Very true. No camera can be expected to survive violent events without consequence. People sometimes expect a little too much.

A 16mm ARRI film camera went around the world three times with legendary yachtsman John Sanders and is now in the WA Maritime Museum.

An original ARRI Alexa was in a fire but was still working afterwards. It was apparently on display in ARRI's headquarters all munted by the fire but operating.

The original "Big" Ursa like the SI2K and the ARRI Alexa was very robust. They all require a person to be prepared for some heavy exercise to carry around, set up and operate. With the heavier cameras, the lens is the more likely casualty.

In the quest for utility, smaller size and lightness of weight, something has to give way. There is absolutely no fat in the structures of the JVC GY HD*** family of cameras. There is no fat in the structures of the Ursa Mini family of cameras.

The direction of the fall and what hits ground first determines just how dead some become. The Ursa Mini 4.6K, which I reconstructed using the Ursa Mini Pro pieces had been absolutely ruined structurally but the electronics survived.

It appeared to have fallen directly forward, possibly onto the top handle and lens. It appears that side falls are most likely to end an Ursa Mini/Mini Pro.

People need to perhaps learn to take more care at all times with somebody's hand on the camera in a busy environment.
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Robert Baker

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Re: URSA MINI SEMI-PRO 4.6K???

PostSun Jan 02, 2022 9:05 pm

Thanks for letting us join you on this journey. It takes me back to the days when I couldn't afford new equipment and would have to build from parts.
Who'm I kidding! I still can't afford new equipment!
Small List of my current toolset:

BMPCC6k - EVA1 - GH5 - Canon R - DaVinci Resolve Studio - Adobe CC - Sony Soundforge 11 - Izotope RX7 - Izotope Elements
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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostTue Oct 25, 2022 12:43 pm

It has been a while but the Ursa 4.6K semi-pro is still going perfectly fine. I took it to the airfield again and it did not miss a beat.

The swing out screen looks a bit third world with a crack in the case and the hinge exposed. I have another to replace it but am also wary of fixing what is not functionally broke lest something goes wrong.

Presently I am in the throes of trying breathe life back into a proper Mini Pro with built-in ND filters and other fruitful things like BRAW, the same old story of accumulating a few wrecks then mixing and matching.

This sick one is a bit of a conundrum. The vibes during shipping must have revived something. When it is cold, it starts like it is fit and well but mostly it sits all sullen and dark in the manner Mini Pros seem to end according to a few mentions in forums.

There was not much warm air coming out of it like the semi-pro. So my assumption, maybe wrong was that the thermal bond between the heatsinks and the respective sensor and main processor might have deteriorated. The fan was turning.

So I opened the machine up, took it all apart thinking that at least I would have box of matching bits for another wreck which is still on its way. So much for that notion. There have been revisions between Mini Pros and Mini Pros.

So there is something to be said for Blackmagic. They are not sitting on their hands but making incremental hardware improvements in their products.

I re-dressed the thermal bonds and re-assembled the camera, switched it on and HAPPY DAY, it worked, then I switched it off and switched it on again and again it worked. Then I put a mug of tea down on the table and the picture went black.

I turned it off and back on again and the dull featureless black screen of demise was there again. A run of turn-ons and turn-offs yielded no life at all. Then as I turned it off again for last time with intention to surrender it to the parts box, I rested my hand on the handle to hold myself upright while shifting feet ( stuffed right ankle ).

HALF DEAD URSA.jpg
HALF DEAD URSA.jpg (205.19 KiB) Viewed 1553 times


As the machine was going back to sleep, all the displays lit up and there was a picture for a brief moment until it finished shutting down. It seems that either the sensor board itself is vulnerable to disturbance or the strip connector might be dodgey. The right side cover was still off when this happened.

It turns out that if the strip connector is forced and held rearward during the switch on, everyting starts and runs, blacks out for a moment then comes back on again when the pressure is released. In this state it happily runs for up to two hours without things becoming excessively hot.

Switch it off and switch it on again and the vacant deathstare from the blank screens is back again and to get it running again, the same ritual of holding pressure rearwards against the strip connector has to happen again.

My first money was on the sensor board having got hot and opened up some solder ball joints which were making contact when cold and opening up when warmed, closing when some mechanical stress was put on the board and things working again.

Due to the strange way the picture comes on and off when the strip connector is disturbed my bet is now on the strip connector itself and that is where it gets interesting. It does not come apart but appears to have been bonded to the ribbon cable. So that is that.

I have no idea if the traces in ribbon cables are punctured with conductive spikes like the spark plug leads from hell on lawnmowers or some sort of soldering arrangement happens. It would have to be damn good soldering.

I should have studied electronics in my younger years.

Here is a short clip from the airfield shot on the Ursa Mini "Semi Pro".

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drknsss

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Re: URSA MINI SEMI-PRO 4.6K???

PostTue Oct 25, 2022 2:49 pm

This guys posts read like Lord of the Rings! love it. I also have found many deals on gear because most do not want to fix things..., Back in the day a few people I worked with invented products for themselves and then sold the rights to a bigger manufacturer. Camera Operators solved problems by building custom gear. If it does the job its don't matter that much how much it costs unless you are trying to impress a client with how nice you gear looks.

Thanks Robert for sharing your story.
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Re: URSA MINI SEMI-PRO 4.6K???

PostTue Oct 25, 2022 5:58 pm

Old Ursas don't die they go to Robert :)
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robert Hart

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Re: URSA MINI SEMI-PRO 4.6K???

PostWed Oct 26, 2022 7:53 am

Steve Fishwick wrote:Old Ursas don't die they go to Robert :)


Nope. They just breed up like back paddock cars. ( Steptoe Syndrome ).

There is an Ursa Mini Pro grazing presently. It is on the cusp of being a goer, so long as I keep my finger on the ribbon cable plug. The improved dynamic range is quite apparent. I wonder how that would impress at an event or a film shoot, the camera assistant standing like a dumb ox with a finger poking into the innards via a removed side-cover?

Probably right up there with the burned Arri Alexa on its display shelf in the Arri front reception in Munich still operating underneath its charred exterior after being in a fire.

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