Dismantle flash gun - safe ?

Had a bit of a problem with my flash - it got stuck on my Yongnuo 622.

In bad light, I went to remove it from the 622 (to put it direct on the camera) but tighened it instead of undoing it. There was a click, but the flash would not come off, I guessed that the flash foot locking pin had slipped out of some sort of screw in the locking wheel.

I have opened up and taken apart the 622 and have removed the flash (sure enough, the locking pin does not retract). The next step is to dismantle the flash to investigate and hopefully reset the pin.

It is a Jessops 360AFDC flash unit (the company went bust last month) and is about 6 months old. Maybe, if I can't fix it, it is time to look at the Yongnuo 568 HSS units.

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safe to open it? Sure...

Safe to touch the innards w/o knowing what you're doing? highly not recommended

If you are not familiar with working around high voltage capacitors, then I would strongly suggest finding someone else to give you a hand.

In general they are safe enough to dismantle if you know what you are doing, but if it is your first time handling something containing high voltage caps then you are risking a lot. There is more than enough power in a small flash head to KILL you if you screw up. Be safe, be smart, work slow and carefully. Think before you act.

And don't go licking random parts to see what they taste like...

(Depending on exact details of design it may be possible to solve your problem without exposing dangerous bits. Totally possible to learn how to work with this stuff safely and isn't something one really should fear, just be well aware of the risks and take suitable precautions.)

Cheers guys, especially for the quick responces.

Looking a little closer at the flash unit, it looks like base comes away with the removal of 4 screws (there are a further 4 screws on top, hidden by the swivel head, that I guess retain the innards).

I've meddled with electrickery for many years (domestic, automotive, electronic & PC), so I'm comfortable with having a look - I just was wondering about any remaining capacative charge - sounds like my suspisions are correct.

I'll leave it a couple of days (it allways takes longer to charge after a rest) and have an exploritory look then. In the mean time, I'll go and lick a 9V PP3

Oh, the 622 is back together and working (even managed to refit those miniscule springs).

Cheers
Lawrence

Lawrence: The norm is that the 'locking pin' is spring loaded in the down position and is retracted by a tiny plastic lug. It's likely that you've sheared this lug (if so, good luck even finding the bit never mind glueing it back in place ) in which case your spring-loaded pin will be permanantly in the down position.

The primary function of this pin is to locate and orientate the hot-foot in the shoe. If you simply remove it and the spring, you'd still be able to use the flash (but it wouldn't be particularly securely fixed). All you need do is remove the foot (nothing nasty inside there) and perform that minor surgery.

Beware licking PP3 terminals, some of the "lesser" brands aren't stored in sterile conditions but Duracells are supposed to be OK. A little Tabasco on the terminals would make it a more stimulating experience for you.

Luckless wrote in post #15602813
If you are not familiar with working around high voltage capacitors, then I would strongly suggest finding someone else to give you a hand.

In general they are safe enough to dismantle if you know what you are doing, but if it is your first time handling something containing high voltage caps then you are risking a lot. There is more than enough power in a small flash head to KILL you if you screw up. Be safe, be smart, work slow and carefully. Think before you act.

And don't go licking random parts to see what they taste like...

(Depending on exact details of design it may be possible to solve your problem without exposing dangerous bits. Totally possible to learn how to work with this stuff safely and isn't something one really should fear, just be well aware of the risks and take suitable precautions.)

Negative........hurt like hell?......burn a hole in your finger?...yes. Dead? No. Not enough current.

Just stay away from the capacitor terminals and you'll have no great surprises.

saea501 wrote in post #15603126
Negative........hurt like hell?......burn a hole in your finger?...yes. Dead? No. Not enough current.

Just stay away from the capacitor terminals and you'll have no great surprises.

In the 1960s, I did see someone dissemble a smaller unit than this, touch both ends of the capacitor bank and get thrown across a room. Spent a few days in Coronary Care in the local hospital being monitored. Best avoided, I'd suggest, unless you are 100% sure of the condition of your heart (the guy in question was a Royal Air Force PTI and extremely fit). Shouldn't be fatal though. Shouldn't.

saea501 wrote in post #15603126
Negative........hurt like hell?......burn a hole in your finger?...yes. Dead? No. Not enough current.

Just stay away from the capacitor terminals and you'll have no great surprises.

Having given CPR to someone goofing around with a similar flash unit, I'm going to have to say you are wrong.

I also never said it was Likely to kill you if you screwed up, nor did I say that it was a death sentence to play with the guts of a flash unit, merely that it can.

It is also entirely possible to kill yourself with that kind of current without the current being the lethal factor. Kid in high school took apart a disposable camera to make a shock device as a prank. Was coming up behind someone on a set of stairs, fumbled the device, and took a drive back down three flights of stairs: Several months recovery in hospital and doctors weren't sure he was going to make it at first.

A girl in my digital systems class back in university knocked herself off her chair when she miswired a circuit and blew a small IC logic gate. The current didn't even touch her, she jumped at the pop made from the blowing chip. Banged her head very nicely.

Well, the good news is that 1. the flash gun is back together and working and 2. I'm alive without any trace of any electrical burns

First step was to remove the 4 screws near the base for a looksee:

Whortleberry wrote in post #15603048
...The norm is that the 'locking pin' is spring loaded in the down position and is retracted by a tiny plastic lug. It's likely that you've sheared this lug (if so, good luck even finding the bit never mind glueing it back in place ) in which case your spring-loaded pin will be permanantly in the down position...

Whortleberry wrote in post #15603192
In the 1960s, I did see someone dissemble a smaller unit than this, touch both ends of the capacitor bank and get thrown across a room. Spent a few days in Coronary Care in the local hospital being monitored. Best avoided, I'd suggest, unless you are 100% sure of the condition of your heart (the guy in question was a Royal Air Force PTI and extremely fit). Shouldn't be fatal though. Shouldn't.

My boss was shocked by the flash capacitor in a "super zoom" point and shoot a couple of years ago.
He twitched hard enought to seriously hurt his neck, and kick himself (sitting on a typical desk chair with wheels) across the room.

This was just dismantling the camera so he could discharge the capacitor.

I have the burnt patch on my finger still, 3 years after zapping myself.

I don't miss working on cameras, especially little point and shoots with hidden connections to the capacitors making it easy to zap yourself.

I never worked on flash units, just little point and shoots - they were bad enough
I wouldn't go poking around In a speedlite - it may not kill you, but even if it's mostly discharged it will still hurt like hell (voltage at the capacitor is typically 300v)