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Deco Rico

Member Since 29 Nov 2012
Offline Last Active Nov 25 2014 10:02 PM
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#323573 Getting inside a DS50

Posted by Deco Rico on 01 January 2013 - 01:06 AM

Here's my teardown of the Ikelite AF-35 strobe, it describes how I got two failed AF-35s back into working order. Since the Ikelite DS-50 and DS-51 strobe casings are basically identical, I expect this also applies to them. Hopefully this helps someone.

Warnings

1. Opening your strobe will void your warranty. I'd suggest only doing this if (a) you think you know what is wrong and how you would fix it, and (b) you are pretty sure that having Ikelite repair your strobe is not cost effective. Why not shoot them an email explaining the problem first. From some countries the cost of postage to the US will make the repair not cost-effective, even if Ikelite will repair it for free.
2. Your strobe contains a large capacitor, which is a dangerous electronic component that stores electric charge. It can give you a severe electric shock, even after the strobe is turned off and the batteries removed.
3. This guide may have errors. In fact I may be a complete idiot. Following the advice of a complete idiot may damage or destroy your strobe.
Basically, you open a strobe at your own risk.

Removing the front lens cover

1. Remove the batteries. If the strobe has recently been powered up, try to ensure it is fully discharged by turning it on and off a few times. If it flashes, that is a good sign, but doesn't guarantee the capacitor is fully discharged. So be careful!!
2. Remove the screw that holds the strobe head onto the strobe arm and also holds the front cover on.
3. Slide the front cover (dark grey on the DS-50/51, black on the AF-35) off the front of the strobe. You may need a little leverage, like a thin flat-bladed screwdriver worked carefully into the crack. This can't really damage anything.
4. The front lens is held on from the inside by two screw heads (circled in green). To unlock the front lens, you need to rotate it about 10 degrees clockwise. Ikelite would do this with a special tool that fits into the 4 small shallow holes around the edge of the lens (circled in yellow). (In the photo, the sticker under the lens has been removed so you can see the locking mechanism.)
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I used two thin allen keys held in a vice, it worked very well. Otherwise you need to rig up your own tool.
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Even after unlocking the front lens, it probably won't fall out as it is held in place by an O-ring, as well as sand, salt and other muck stuck in the gap, and excess plastic around the locking screws. There may also be a bit of negative pressure inside the strobe "sucking" the lens into place. The lens fits very snugly into the strobe and there is no room to work a tool down the side of the lens. So we need to resort to the Ideal Gas Law....
5. Get a container of warm water -- around 60C/140F seems to work well. Check that the strobe's battery door and sync cable connector are watertight. Put the strobe in with the lens facing upwards, keeping the lens above the water level so that water doesn't get in. The strobe will be buoyant, so be careful it does not tip. After a few minutes you should notice the lens has lifted slightly on one side, and you will be able to work a very thin tool into the gap and gradually lever the lens out. Don't push the tool more than a few mm down as there is an O-ring around the outside of the lens that could be damaged.

Inside the strobe is a PCB, dominated by a large capacitor (circled in green). Remember that large capacitors are dangerous and can give you a severe electric shock. On the other side of the PCB is a small incandescent lamp (location circled in yellow) that appears to show the amount of charge in the capacitor (this is separate to the lamp visible from outside the strobe). There are two short wires connecting the PCB to the battery compartment. Unfortunately these wires are too short to lift the PCB out while they are connected.
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This last photo shows excess plastic around one of the two locking screws that hold the front lens on. This is partly why the lens is hard to get off, even after unlocking it.
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What you do next depends on the fault. I have fixed two faults, as follows:

Fixing a flooded battery compartment

The first strobe had a flood confined to the battery compartment, and the spring terminals inside the battery compartment were rusted out while the rest of the strobe was fine. Here is how I fixed this:
1. Undo the wires to the battery terminals using a 3/16" socket driver. Each battery terminal has a 3/16" nut, under that is the wire itself, under that is a washer, and finally a tiny O-ring. You may need to use a Philips head screwdriver in the battery compartment to stop the screw turning as you turn the nut. Don't undo the middle nut which is attached to the post inside the battery compartment.
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You can also see why trying to unscrew the screws from inside the battery compartment is a bad idea -- the nut on the inside also turns, winds the wire around itself and eventually the wire would break.
2. Remove the screws and the small PCB with the battery terminals from the battery compartment.
3. Solder up some new terminals on the PCB. The photo below shows how it is SUPPOSED to look :-) Check your work with a multimeter.
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4. Reassemble by reversing the steps above. You might clean the parts in an ultrasonic cleaner first.
Note that these terminals are initially watertight (or at least, they are meant to be). After disassembling and reassembling them, they almost certainly won't be. Ikelite used some kind of brittle sealant that cracks off when the nut is undone, and I don't know how to repair this. So, don't flood your battery compartment again as the water will probably reach the PCB and kill your strobe stone dead!!

Fixing a minor leak in the power switch

The second strobe had a slight leak through the power switch on the back, which was just enough to short out the switch. The result was that the strobe would stay turned on after use, even with the switch turned to the "off" position, until the batteries were flat. Here is how I fixed this:
1. The PCB has two short wires connecting it to the battery compartment, unfortunately these wires are too short to lift the PCB out. I disconnected the wires from the battery terminals as explained above, but in retrospect I should have just cut the wires and rejoined them afterwards. It would have been quicker, and also the terminals of this strobe were (probably) watertight before I undid them, and almost certainly weren't watertight after I reassembled them.
2. With a fine marker pen, mark the position of the top of the PCB on the inside of the strobe. This will help with reassembly. Lift the PCB out of the strobe. Did I mention that large capacitors are dangerous?
3. Look for corrosion on the PCB. As expected, I found corrosion around the electronic switch on the PCB (left). Compare this with the other, undamaged strobe (right). I scrubbed the corrosion away with an old toothbrush. Also look inside the strobe's case for dried salt etc which may indicate leaks.
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4. Unscrew the Philips head screw inside the strobe that holds the plastic parts of the power switch in place. Carefully remove the plastic parts -- one inside, one outside -- as there is a tiny loose ball bearing under the outer plastic part that can get lost. This photo shows the ball bearing, and the spring on the underside of the outer plastic part that the ball bearing fits against:
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5. Remove the switch's O-ring from outside the strobe, clean it and check for sand and damage. In this photo you can also see the dimples that the ball bearing sits in when the switch is turned:
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6. Re-seat the cleaned O-ring and reassemble the plastic parts of the power switch into the strobe, with the ball bearing in place. Tighten the screw well as I think my leak was caused by the screw being slightly loose.
7. Turn the plastic parts of the power switch to the "Off" position, and turn the electronic switch on the PCB to position "9". This ensures the two will fit together when the PCB is reinserted. Slide in the PCB until it reaches the mark you made earlier.
8. Reconnect the battery terminals. If you cut the wires at step 1, check that the joins are insulated properly and can't come undone, as they will always do so at the worst possible time (when there are 6 mermaids dancing in front of your camera).
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