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WARNING: JTL Monolights are DANGEROUS!



 
 
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  #11  
Old October 23rd 03, 05:09 PM
Art Begun
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Posts: n/a
Default WARNING: JTL Monolights are DANGEROUS!

Those testers are available at Lowes, Home Depot and Radio Shack.


"Jack" wrote in message
...
On Mon, 20 Oct 2003 18:31:38 -0500, "Ken Hart"

wrote:


"John Steven" wrote in message
. com...
FYI: I recently discovered the hard way that the three JTL

monolights
(Versalight series, 300 and 800) I owned are ELECTRICAL HAZARDS.
CAUTION: you may get shocked quite severely if you use these

lights. I
found this out by getting a good shock when doing a portrait

session
in a studio with a concrete floor. I was wearing shorts and knelt

down
to get a better angle on the subject and as soon as my knee

touched
the floor, I felt a strong electrical current run through my arms

via
the camera. I measured 85 volts AC between the sync cable outer
connector and earth ground. THIS IS NOT NORMAL!! I tried

contacting
the JTL company twice but did not receive a response. The same

problem
was exhibited by all three lights, so I don't think it's an

individual
defect. Instead, it seems to be a design flaw.

Yes, you might say I was an idiot for wearing shorts and shooting
portraits in a room with a concrete floor, etc. I agree, and I'll

not
do that again. However, I recently took delivery of some new
monolights (from Calumet) and they do not exhibit this voltage
problem.

-John


Do the strobes have a plug with one prong slightly wider than the

other?
Does the outlet also have one slot larger than the other? The

larger slot
should be at earth ground potential (get the voltmeter back out!).

If not,
your outlets are wired backwards, and could cause similar problems

with
other devices plugged in these outlets, particularly those with a

wide
prong. ("polarized plug")

Ken Hart


Even so, polarized power outlets, *especially the 2-pin variety* are
dangerous because there is no way of knowing whether the outlet was
wired properly. Should the wires be internally reversed, you have

an
electrical shock / fire hazard just waiting to happen. I've seen

all
too many improperly wired outlets in my years as an electrician.

Many
were even wired by licensed electricians, not simply home-handymen!

Outlet Testers (The round yellow plug-in ones with 3 little neon
lamps - at least those in the USA) are cheap and will tell you if
theres a problem. I consider them part of the kit of anybody who
deals with electrical equipment, including studio and stage

lighting.
And I consider an inexpensive multimeter essential, too. Also good

for
checking cables for continuity, etc.

-Jack-



  #12  
Old February 9th 04, 02:30 AM
KBob
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Posts: n/a
Default WARNING: JTL Monolights are DANGEROUS!

On 20 Oct 2003 11:54:07 -0700, (John Steven)
wrote:

FYI: I recently discovered the hard way that the three JTL monolights
(Versalight series, 300 and 800) I owned are ELECTRICAL HAZARDS.
CAUTION: you may get shocked quite severely if you use these lights. I
found this out by getting a good shock when doing a portrait session
in a studio with a concrete floor. I was wearing shorts and knelt down
to get a better angle on the subject and as soon as my knee touched
the floor, I felt a strong electrical current run through my arms via
the camera. I measured 85 volts AC between the sync cable outer
connector and earth ground. THIS IS NOT NORMAL!! I tried contacting
the JTL company twice but did not receive a response. The same problem
was exhibited by all three lights, so I don't think it's an individual
defect. Instead, it seems to be a design flaw.

Yes, you might say I was an idiot for wearing shorts and shooting
portraits in a room with a concrete floor, etc. I agree, and I'll not
do that again. However, I recently took delivery of some new
monolights (from Calumet) and they do not exhibit this voltage
problem.

-John


Sounds as if the internal design may involve an AC-DC converter that
does not use an isolation transformer, i.e. the worst kind of cheapo
engineering. The problem you experienced is clearly a severe design
flaw and safety hazard, possibly the result of a failure to connect
the neutral of the supply to the proper pin of the plug, and the
ground pin (if used) of the cord is probably not terminated to the
metallic structure (at least the mounting flange & flash bowl support)
of the flash . No flash unit should need to depend on having the plug
properly polarized, however--your safety should not depend on whether
the plug is shoved in one way or the other. This is of particular
concern for electronic studio flash units where potentially lethal
voltages are present, and when these voltages are backed up by large
capacitors that hazard is made all the more serious.

See if the JTL units carry the UL sticker, and if so threaten to turn
them in and do it. Consider contacting the BBB and Interstate
Commerce Commision about this. Tell them to fix these correctly or
you want a total and immediate refund. JTL has an extremely poor
reputation for dealing with customers and they are likely to jack you
around, expecting YOU to pay for their mistake. Their head guy got
his start working for Britek, and that should tell you something.
Their products are cheaply made in China and JTL (in the US) doesn't
even seem to have a clue as to what's inside them. They are located in
La Marinda, Calif.I hope this won't be an expensive learning
experience; at least try to post your experience in the various camera
discussion groups so that others can profit. Since Adorama is a major
outlet for JTL, you might also inform them of your experience.

Lest anyone think these lamps are some kind of bargain, keep in mind
that the Versalight 800 sells for $550, and that's more than I paid
for a like-new Elinchrom 1000 W-S monolight that's a real pleasure to
use. Speedotron, Norman, Elinchrom, Comet and Dyna-Lite are brands
trusted by pros to deliver, they cost a little more but work out
better in the long run IMHO.

Here's someone else's bad experiences with JTL:
http://www.photo.net/bboard/q-and-a-...?msg_id=005Gl6
  #13  
Old February 9th 04, 01:46 PM
Dennis O'Connor
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Posts: n/a
Default WARNING: JTL Monolights are DANGEROUS!

This is an old, and very, dead horse, well flogged on this group months
ago... Check the dates on the posting and look at the archives...
denny

"KBob" wrote in message
...
On 20 Oct 2003 11:54:07 -0700, (John Steven)
wrote:

FYI: I recently discovered the hard way that the three JTL monolights
(Versalight series, 300 and 800) I owned are ELECTRICAL HAZARDS.



 




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