Peter Burgess said:
ghost said:
If you're determined to use a Duo, so be it ....
... very soon become a source of despair.
There was no determined attitude in my case. I saw others using them, asked what they were like, and made up my mind based on reason and budgetary considerations.
No, mine did not become a "source of despair". Not very soon, nor after several years. Those I know who have replaced them did so because they could afford a top of the range lamp. Others have kept them and upgraded, which I don't think they would have done had their lamps been a source of despair.
Here are quotes from a few unhappy Duo users on this very forum. Their words, not mine:
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First the recent problem with the yellow battery case. Four AA batteries are mounted in a black carriage with a yellow top. The carriage is clipped into the yellow case by two metal clips which create a water tight seal with a d-ring.
The yellow top to the carriage has cracked and broken completely. This is a result of the pressure applied by the two metal clips. Previously I had been surprised by the force applied by these clips when putting the batteries in the case. When I mentioned the problem to Tim on a recent trip to Shatter pot
he discovered that his nearly new duo also had a crack (so new it may be within warranty).
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The second problem with the duo which I have lived with almost as long as I have had the light is that
it is nearly impossible to open
even when brand new and certainly not after a few caving trips have got dirt into it. We have tried hot water soaking etc..
brand new duos (almost everyone in our tiny club has duos). This became an issue when someone wanted to replace the halogen bulb with an led
and we failed to open it. It became a more important issue when my halogen bulb failed. However since I almost never used the
halogen light except accidentally this was not an issue either. However it is
another example of a design flaw in the
petzl duo lighting system.
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I recently noticed that mine wasn't as bright as i remembered and probing around with the mutimeter showed high resistance (100ohms ) between the battery terminals and the bulb contacts, so stripped it down and replaced the wiring.
the knife edge contacts to the cable are a point of failure with the duo. soldering the wires on improves things but soldering to stainless steel is tricky to do as the solder doesn't take too well.
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I found when I took mine apart, the ends of the wire had corroded and gone green. Replacing the wire was easy enough
but now, despite silicon sealant, the whole unit lets in water. Not disatrously but enough to have little beads of damp between the LEDs and the lens.
So be careful -
these things don't like being taken apart, and as you can see from Christian's pics they are a bit "mickey mouse" inside - especially the switching system.
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Judging by the amount of people on and off this forum with similar stories its safe to say that they are not waterproof and only last about a year (of average use, and average maintenance**) before the wires corrode, resistance goes up and brightness goes down...
** there will be exceptions to this rule
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One funny thing I noticed - for the one-off mod I was thinking of for a friend, I was trying to work out possibilities for a switch -
the regular switch lever seems only to be held into the headset by the switch contacts, so I was thinking of maybe ignoring that and doing something using the focussing lever as a more solid control.
In my headset, that lever was stiff, so a month or so ago, I tried a little silicon grease on it and that made it much worse.
Just playing around with it now, it has greatly freed up, and is much freer than it was before the grease was applied, despite me doing nothing but leave it alone.
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I guess
the wires had gone green due to moisture, I noticed a lack of brightness after a year or so then decided to operate on it.
Yes, it was bathroom silicon -
around the wire entry point as there should be no movement there.
The O rings which "seal" the switch and zoom control are also poxy, in fact the more I write the less I like about it.......
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So has anybody come up with a way of properly sealing a duo yet?
I'm having to keep on opening mine up to dry it out and it flickers like crazy.
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Have a look in the bottom of the battery box if its flickering the last one i repaired had corrosion between the flexy cable and the stainless battery contact
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None of these faults are acceptable for a caving lamp, which is after all an activity which has a tendency to place you in life or death situations. The Duo has lowered people's expectations about what constitutes a reliable lamp.
Roy Fellows, one of the UK's most respected lamp builders, concluded: "By the look of it the Duo is not fit for purpose, end of."