Lying around the house I had an old Achiever TZ 250 flash unit and in another cupboard my wife had a Canon EOS 350D. I’d been asked to take some photos at a breakfast and I thought I’d bring these two superseded photographic toys together.
The flash is around 15 years old, bought when I was still using my trusty old Pentax K1000 (I found a roll of film in it). A quick search around the net raised some important issues regarding old pre-digital flashes on our new digital SLRs. Amongst the reading material I came across, this was probably most useful Trigger voltages and this was great at filling me in on how Flash photography works with our Canon camera.
I measured the Achiever trigger voltage to be 7.2V, which is close to the 7V to 8V I noticed other people mention. This was fine as most reports suggest that the 350D can supposedly handle trigger voltages up to 250V. (WARNING: this is not the same for all Canon cameras, and definitely not the same for all manufacturers. There is conjecture as to whether this is even correct for the 350D).
Also noticed it had reverse polarity. This would definitely cause the flash not to fire, but this was something I could fix.Anything you do is at your own risk. Do your own reading and learning before attempting anything. I’m not responsible if you break something or hurt yourself.
1. Remove the batteries
You might only have 4 AA batteries in flash unit, but they store very high voltages in the capacitors. Enough to really hurt.
2. Remove the screws from the hotshoe
There are 4 small screws to remove. Be gentle when you pull the hotshoe away from the main unit – the wires are only just long enough for you to see what is inside.
The 2 wires to change are black and grey.
3. Swap the wires
I did this by removing the screws that hold the metal tabs in the plastic housing. It was then easy to get my soldering iron to remove the wires from the tabs and then attach them to the other tabs.
At this stage I put the flash unit back together and jammed it onto the camera. Nothing. The flash wouldn’t fire. I knew that the flash worked (It fired perfectly on the Pentax). I considered that the 350D might be a little broken, but there was one thing I wanted to try before I gave up.
4. Snip the other coloured wires
They won’t be used by newer cameras. WARNING: Don’t do this if you still use this flash unit with a compatible film camera; you will lose some features.
After snipping the other wires (I only cut the orange, brown and green), I put it back together again, and to my satisfaction the flash fired!
You would be better served to buy a new flash unit, one that adjust the flash output based on the requirements of the scene you are trying to capture. This old flash will effectively fire at full strength, but that’s fine for me, for now.