A search of the internet failed to produce any helpful information on disassembling the flash. One video was purported to show a AF500FTZ that wasn’t working. They literally showed you the unit didn’t work. Talk about not being helpful…
It wasn’t my first attempt at repairing an electronic flash. The caution should be made here that electronic flash can kill you—the charged main capacitor can melt the end off a screwdriver, so take some precautions—
- Take out the batteries and let the unit sit for 24-hours to self-discharge the capacitor.
- The dangerous capacitor is a large can with two connections at one end-DON’T LET ANY PART OF YOU BRIDGE THOSE CONNECTIONS. (although this can shock you and possibly burn your skin, it hopefully won’t kill you).
- The capacitor is also connected to the flash tube—don’t short out these two connections either.Generally you fear having one hand on a ground and the other hand on the short as this way the shock could travel through your heart (and stop it) For example you could reach out to change the sound system—which is grounded— and accidentally have the other hand droop into the electronic flash’s connections—resulting in death.
Anyway we are going to tell you how to take this style of flash apart. The base unit has a front and back cover. These covers are attached with small metal plates with screws on both sides. The major tip here is you only need to remove the one screw in each pair. And generally it is better to remove the same side’s screw in every location. You can see the two screw pairs in this bottom view. I decided to always remove the screws attaching the back half.
Then you rotate the head at right angles to expose the top pair of screws on one side. Remove the screw on the back half of the base (left screw).
Swivel the head 180ยบ and remove the screw on the back half (right screw).
You can now gently pry the shell halves apart and the whole top head will fall out of the base (still connected with a small bunch of wires).
The entire front cover of the flash head has to be pried off. It is a snap fit so you have to very carefully feel where the weakest part of the head cover is snapped in place (hint: it is generally in the longest sections top and bottom, not the shorter side sections). You have to gently get under a nearly nonexistent joint to lift the front plastic enough the plastic can pop off. And to get to the release points the Velcro™ pads—aftermarket strips to hold a flash modifier in place— have to come off where ever they bridge between the front snout and head.
The top head is held together with pairs of screws located under the hinge ends. The AF500FTZ has lovely rubber hinge end covers that are a joy to remove and replace. You need something to slip under the rubber like a fork tine, a dental probe, the tip of an electronic meter’s probe… Once lifted a little you can gently pry the rubber off the plastic. Again remove the top screws on each side…
At this stage you are going to be scared. For example the small rubber port cover just above the battery compartment is hinged into both sides of the two shells. So when you opened the unit the rubber cover fights you. Behind the cover the two connectors (power and remote cable) again bridge the two shells and they fight letting go. You find wires running to connectors strung between the shells. Then when you get the head apart you find wires running everywhere in small pathways.
DON”T PANIC! As long as you haven’t completely twisted the parts around everything can and will get tucked back out of trouble. You have to keep checking and gently persuading but reassembly will be possible.
Back to what was wrong.
I haven’t mentioned that when the unit wasn’t working, if I shook it you could hear something bouncing around in the head part. Turns out it was a small gear that had come off the motor shaft. It connects the motor to a worm gear that moves the flash tube back and forth. I suspect the flash has to know where the flash head is so the first step of firing up is the motor tries to move the tube to get feedback as to where the tube is.
Upon examination the small gear has a side that cups the shaft and a flat side with a hole in it smaller than the shaft diameter. I just slid the gear back on the motor shaft until it stopped. Then I instant glued the gear by placing a dab of the glue on that small hole so the shaft and the plastic gear are bonded together. I probably should have tried to glue to the other side of the gear too—to have a better bond—but there isn’t much room and instant glue can seriously gum things up…
A careful repair person might be tempted to loosely place everything together enough to power it up to see if it was fixed. For example you don’t need the connector cover or the hub rubber covers or the front flash head cover back in place.
I am not that kind of person—I bravely reassembled everything. As usual there were many small problems. Tucking wires before getting them caught between plastic joints, fitting the head back into the base unit, the hard plastic connector unit fitting between the two base halves and don’t even mention the rubber connector cover…
But surprisingly soon the unit was back together. I walked away for most of a day to be sure the glue had set before I proceeded. While I was waiting I took another look at the battery connections in the flash. I wanted to be sure the flash had every chance at powering up.
Can you imagine the suspense as you bravely load the batteries and try turning the unit on? I was rewarded by the display coming to life. Better yet the flash zoom head moved the tube back and forth. And when the test button was pressed and the flash fired the joy felt was incredible.
Of course, because I am not that talented I could be a repair person for Pentax, there are small matters not done well. For example the aforementioned connection mount isn’t perfect as is the rubber cover that stands slightly away at the top hinge area.
And if you look closely you will see a small crack in the front snout’s plastic.
Still, you’ve taken a fancy paperweight to the point of being useful. You’ve occupied a couple of hours. You’ve earned some self-congratulations for fixing something. Who knows, maybe next time you will do an even better job.
Upon examination the small gear has a side that cups the shaft and a flat side with a hole in it smaller than the shaft diameter. I just slid the gear back on the motor shaft until it stopped. Then I instant glued the gear by placing a dab of the glue on that small hole so the shaft and the plastic gear are bonded together. I probably should have tried to glue to the other side of the gear too—to have a better bond—but there isn’t much room and instant glue can seriously gum things up…
A careful repair person might be tempted to loosely place everything together enough to power it up to see if it was fixed. For example you don’t need the connector cover or the hub rubber covers or the front flash head cover back in place.
I am not that kind of person—I bravely reassembled everything. As usual there were many small problems. Tucking wires before getting them caught between plastic joints, fitting the head back into the base unit, the hard plastic connector unit fitting between the two base halves and don’t even mention the rubber connector cover…
But surprisingly soon the unit was back together. I walked away for most of a day to be sure the glue had set before I proceeded. While I was waiting I took another look at the battery connections in the flash. I wanted to be sure the flash had every chance at powering up.
Can you imagine the suspense as you bravely load the batteries and try turning the unit on? I was rewarded by the display coming to life. Better yet the flash zoom head moved the tube back and forth. And when the test button was pressed and the flash fired the joy felt was incredible.
Of course, because I am not that talented I could be a repair person for Pentax, there are small matters not done well. For example the aforementioned connection mount isn’t perfect as is the rubber cover that stands slightly away at the top hinge area.
Still, you’ve taken a fancy paperweight to the point of being useful. You’ve occupied a couple of hours. You’ve earned some self-congratulations for fixing something. Who knows, maybe next time you will do an even better job.
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