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Old October 29th, 2015, 04:50 PM   #1
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HMI ebay arri knokoff lights from China review

Reviews of the HMI fresnels on Ebay in the Arrisun knock off style are hard to find. So here is mine.

They are garbage.

I've bought 2 different types of the HMIs from different sellers. Each of the ballasts have died twice, one lasting only a week. The heads themselves needed modification as the machining tolerances were bad and one of the bulbs literally fell out of the base in transport.

Neither of the sellers I bought them from would replace the ballast, shipping back for repairs cost $200 and nearly 2 months of downtime. Then it died again. The next time, they offered to sell me a new ballast for $500usd, which I took. It lasted about a month. I gave up at that point.

Also, (and this not exclusive to the knock offs, "real" HMIs have it as well) the colour temps were radically different and they all needed to be gelled. Or more accurately there were weird spectrum spikes.

So, having burned thousands and thousands of dollars on this waste of time, please learn from my difficult lesson on ebay HMI lighting and avoid at all costs.

Just my two cents.
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Old October 30th, 2015, 09:12 AM   #2
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Re: HMI ebay arri knokoff lights from China review

Glad to hear you enjoyed them so much!
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Old November 12th, 2015, 02:54 PM   #3
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Re: HMI ebay arri knokoff lights from China review

Hey Dylan,

Thanks for sharing, because most people are too afraid to share their high priced mistakes.
That takes courage and I applaud you!

I have often seen the Arri knock-offs and wondered about them. Those prices are certainly attractive.
After all, how hard is it to steal Arri's intellectual property?
You buy one, take it apart and exactly duplicate all the components,
then produce your own using slave labor and available electronics (cheap)
then put it on the market at cut rate prices.

I guess the real story is, it ain't that easy and you get what you pay for.

Thanks again!
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Old December 2nd, 2015, 01:32 PM   #4
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Re: HMI ebay arri knokoff lights from China review

The 1.2K HMI I got from Steven Studio, seems to have been adequate. There was shipping damage.to the lamp which had loose components within, which I put right when I opened it up for a damage check.

When you import direct, you are responsible for your own pre-delivery checks. One should not indulge in faith-based operation of just plugging the thing in fresh out of the box and firing away. It is a catch-22. Pull it apart to check it or get somebody else to pull it apart and check it and you potentially void your warranty.

The placement of attaching screws seems different to the ARRI in that the lamphouse end caps are fastened from the ends through holes into C-section slots in the extruded side segments. The ARRI side segments appear to be fastened through holes in the side segments radially into the end caps.

There seems to be two basic styles of electronic ballasts. The cheaper sets seem to use a ballast which bears a passing resemblance to a domestic hobby welder, sheetmetal case, no apparent dense heatsink or finning around the outside.

Other tungsten lamps seem to be less robust. The 650watt fresnels crack their lenses often. I think the globes are allowed to travel too close to the glass. I have backed off the retainers so the lenses are almost loose in their end caps and free from uneven pressures from the structure around them shapeshifting with heat.

I am not very fond of their in-line cable switches.

The lightweight stands are not very robust. They are thin walled steel tube and become easily crush-damaged.

Pressure-friction plates can fall out and thumb-screw ends directly impinge on the thin tube and drill though it if your lighting man is a Green Hulk or a Tarzan. - Game over.

It is one of those "you get what you pay for" things. They are useful in that they comprise the least unaffordable option for someone who would otherwise have to do without. They can endure but require lots of gentle care in handling to avoid damage.

I had two years out of the stands in my own use of them but one lend to a starvo indie project and I ended up some hours driving steel pipe down through the thin-walled tubes of the lighting stands to belt out the dents and punch-holes and making replacements for lost pressure plates.
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Old December 2nd, 2015, 06:06 PM   #5
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Re: HMI ebay arri knokoff lights from China review

Quote:
Originally Posted by Jacques Mersereau View Post
Hey Dylan,

Thanks for sharing, because most people are too afraid to share their high priced mistakes.
That takes courage and I applaud you!
Hey Jacques!
Oh I've made way more expensive mistakes... but those stay in Vegas and only my AmEx knows about them! ;)

I've tried a lot of the Arri tungsten knock offs over the years. For a while, they seem to be equal in every way, even in quality, as the real ones.

However, I have noticed one issue cropping up in the recent knock offs I've tried, and that's that the spot/flood mechanisms have been seizing, possibly due to warping in the screw mechanism due to cheap metal + heat.

Just for what it's worth.

D
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Old December 3rd, 2015, 09:46 AM   #6
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Re: HMI ebay arri knokoff lights from China review

QUOTE:

"However, I have noticed one issue cropping up in the recent knock offs I've tried, and that's that the spot/flood mechanisms have been seizing, possibly due to warping in the screw mechanism due to cheap metal + heat"

Which light is giving you the jamming problem?

You should not have to frig around fixing new lamps, however there are some fixes for different lamps.
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Old December 6th, 2015, 07:05 PM   #7
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Re: HMI ebay arri knokoff lights from China review

I bought a Chinese 575w HMI and no issues to date in the field. The bulb that came with it squealed considerably but it was fine once I replaced it with a high quality bulb. I've used it on day long shoots and no problems.

http://i1119.photobucket.com/albums/...psxcc9o0sl.jpg

Note there is a wide range of Chinese HMI's on ebay, etc.. so it can be hard to know which might be a "good" one compared to a "bad" one.

I went for the one with dimmable electronic ballast, and haven't tried others yet.

Also agree with Bob here, I've advised others to open up the ballast first and check for loose parts or damaged connectors, pots, etc.. anything that could cause premature break. Cable inspection is a must as well.
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Old December 6th, 2015, 09:14 PM   #8
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Re: HMI ebay arri knokoff lights from China review

Dennis.


That looks to be the same ballast as I have for the 1.2k from Steven Studio. Mine is a dual 575/1200 ballast.. You may find eventually that the frequency control switch ( frame rate ) knob will begin to spin on the shaft.

The switch shaft is nylon with splines on my specimen. The knob is retained by a nut and splineless tapered collet arrangement. This crushes the splines and it becomes loose. An urgent workaround on set is to pull outwards as you turn the knob. You'll get one or two extra uses of the switch before this quickfix also fails.

The collet nut is hidden inside the knob. To get at it, you prise a little plastic disk out of the hollow front of the knob with a small jeweller's screwdriver or a splinter-pick. The nut is hidden deep in the recess but a small tube spanner or small rat-nosed pliers can get at it sufficiently to re-tighten it.

This is a curious piece of over-engineering. My guess is that there needed to be a nylon shafted switch to meet the claimed "CE" standards.

In the Steven Studio 1.2K lamphouse, the right-hand support rod for the sliding carriage doubles as the round rail and actuator. There is a square-cut spiral groove machined into the rod. It is cut to an aggressive helix angle and the tendency is for this to baulk and bind until initial wear smooths things out.

In the moving carriage, there are two small locknutted screws with the tips machined down to about 1.5mm diameter. On each tip is fitted a tiny hardened steel roller of about 4mm diameter. My guess is that with a simpler follower pin, the aggressive angle would cause the groove to bind before moving the carriage. In the hot lamphouse there is little chance of effective long-lasting lubrication.

It is important that these screws are adjusted so that the roller is well down within the spiral channel. If it is riding high in the channel, the little roller may eventually work itself high on the little shaft on the end of the screw and wear it down prematurely.

If that eventually happens to point of failure, my fix will be either to machine another replacement screw or to drill the end of the screw and press in a needle roller from an automotive tailshaft. The bearing hole inside the little roller may need to be drilled wider.

This may require heating it to red heat and allowing it to cool slowly to soften the metal, drill it out to fit the needle roller then re-harden it by heating and quenching.

By the time that problem happens the rest of the lamp may have worn out.

If you need to open the lamphouse, the construction method will offer you extreme challenge to get all those silver coloured slats back into place when you close it up again.

You have a better chance of doing it if you wrap several pieces of good sticky gaffer tape around the entire length of the slats before dismantling to keep them in their correct registry with the matching grooves cast into the front and rear covers and to avoid having to need forty-thousand fingers to move everything around.

A second person to help you will still be handy.

Try not to operate the lamp-head in the rain. Besides the obvious hazards to life and limb, the steam condenses inside the lower lamphouse and upsets the circuitry which seems to provoke the ballast into shutting down.

There you go. Some useless information overload but since it was running through my mind, why not post it?

Last edited by Bob Hart; December 6th, 2015 at 09:29 PM. Reason: errors
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