Desisti "Rembrandt" 12K HMI

[Bob Hart]

Those who remember history back might recall one of my less wise adventures, this HMI light which I did not understand at the time ( small matter of 12K versus 1.2K ). Whatever, I have the lamp.

After a good long time, I have finally started on it, going through looking for wear/tear and trouble. The Hobbs meter has 11,000 hours up on it. The reflector has some impact marks on it but it is otherwise good, so somewhere along the line, sombody has been suddenly amazed by something violent.

There are no longer any manuals or handbooks that I can find on the web. Older lamps like this have been built before computer records and .pdf files became part of the archiving process.

I have run into a little puzzle. There were things rolling and rattling as I moved the lamphouse but nothing loose inside. I found in the junction box on the side, a large wingnut and a thrust bearing. It looks like they have been there a long time. Luckily it seems nothing electrical has been touched by these loose metal pieces.

The wingnut does not seem to be missing from anywhere. It is not a fastener for the pigtails on the globe, It is a different size.

The thrust bearing? Goodness knows where that is from? The lamp carriage flood/spot movement appears to be intact and there is not any excessive play in the mechanism except for the cable itself which is adjustable.

If anyone has any exploded diagrams of this lamp or images of its entrails, any info would be appreciated. Details on the placard are :-

Desisti "Rembrandt" mod.2450
S.N. 0191.


Regards all.

[Chris Ficek]

I have a point of contact with the president of DeSisti North America and I will forward your info off to him. He seems like a very decent fellow and I'm sure he can direct you better than anyone. You've actually just reminded me that I owe the community an update on my negative posting about DeSisti at The Colour of Light - Home based on this gentleman's professional response...my bad.

[Bob Hart]

Chris.


Thanks very much for your endeavours on my behalf. It is much appreciated.

I initially was not too impressed with the metal work of the case. I thought it was like something I could bend up with a pair of tin snips except for the pressed vent slots. However I found a channel frame underneath, a much stronger build method, resistant to knocks and bumps.

The deeper I mine in, the better I feel about exloring. There are a few things that need just that little tidy up like insecticide residues. Who ever did the spider kill in the US when the light was shipped didn't muck around or maybe it got another one out here too. I saw a bit of residue when it first arrived which I wiped out.

Having pulled it apart some more, I have found white dried fluid runs, some corrosion and a dead bitey in the junction box.

I also found the shields inside the top have sharp deep dents in them, possible evidence of a globe explosion along with the dents in the reflector,

[Bob Grant]

Pictures please, a video of the first lamp startup would be good.
Hint from the now much wiser, do not look at the lamp as it starts up just to see what happens, I got the worst migraine of my life doing that with a 150W HMI lamp.

[Bob Hart]

Bob.


I should have thought of a before and after sequence, however will video the event.

As for getting a flash, one of my jack-of-all-trades semi-skills is stick welding, so the reflex for avoiding eye injury is well established. Having seen the depth of those sharp dents from flying glass inside, the fresnel door will definitely be shut.

[Bob Hart]

After a long hiatus, I finally got some power into this thing and it lives, searingly bright. The moths have no hope.

[Bob Hart]

Here y'go Bob.

Here's a happysnap of the 1.2K that wasn't.

[Bob Hart]

Well here it is, doing what it is intended to do, images from a short conceptual test for an upcoming project.

The operator in front of the lamp is not me but Steve Rice, (Darling Films) who came along to assist.

Camera. SI2K. Lens. Nikon 85mm f1.4 at f1.8. motion image for end titles at close of teaser clip.

[Brian Drysdale]

How are you powering the 12K? Any time we've used them it has always involved hiring a generator?

[Bob Hart]

Initially the scheme was to test the light on an industry lighting generator however the owner-operator wanted a guarantee for repair of his generator if the light blew it up. At Australian labour costs and given that his truck would have to be pulled apart, repairs and claims for lost work. On the math it could have been easily $8,000 at the kickoff and rising.

It was decided to buy in a $6,300 ( + customs, GST) 20K single phase generator from a US based vendor which ships worldwide. If the light did not perform satisfactorily, the generator could be onsold locally at little or no loss. It is bit more noisy than a double-blimped truck generator but some of the noise is from the panel trailer it is sitting on.

GENERATOR SYNCED TO CAMERA. 25P 50Hz - YouTube

[Brian Drysdale]

Sounds like a bit of an investment just to test a light. I guess the possibility of selling the generator on off sets the risks,

[Bob Hart]

That pretty much was the scheme. I was fairly confident that the ballast and the light would work after giving everything a clean, swabbing the insecticide residues out and metering everything that could be passively metered.

It is one of those situations where to get anything back you must put some more in. Some misgivings there but it's done. One of the proper lighting guys over here expressed interest in buying it if I wanted to sell after it was proven. I understand that most of the few other 12K - 18K HMI lights here have magnetic ballasts. After the current indie movie project is done and dusted, I may then onsell the whole package.

I think in fairness, I should mention a US based lighting tech by name of Gilbert Navarro whose outfit trades as Galaxy Lighting and Repair. He was very helpful despite the likelyhood of not making any profit from his advice to me. His website also has lots of useful information.

I hope Chris will afford me this one indulgence of mentioning a commercial entity who may not be a site sponsor.

Brian. Offtopic. If you were in the film industry on the mainland UK in the seventies-eighties, you might have run into Ricey who was then in set construction and worked on the the original Star Wars series, Hanover Street, Dark Crystal, the first Indiana Jones.


All the best for Christmas and the New Year to all and your own.

[Bob Hart]

A bit of a way to spend a Friday night. Lighting test shot on SI2K.

When daddies go bad... - YouTube

[Bob Grant]

Using a SI2K to test a 12K, that could lead to some confusion :)
That test does seem to show how useful such a light is. A big light source far away looks different to a smaller light source close up. Despite the seemingly huge number of lumens coming out of a 12K, outdoors they don't go that far.

[Bob Hart]

The light was about 300 metres back up the valley. Gavan was not sure how it would go as the lamphead is smaller than 12K lamps he is accustomed to from his 35mm film TVC and Singapore/Jakarta days. He is content it will do what will be wanted for a teens in the bush in jeopardy project.

With the big stand and the power needed and just three bodies to move stuff around and do the shots, it is not a redhead to bung here and there on impulse. One needs to plan and scheme.