Metz CL-4 recharging problem

Some info about batteries.. I've successfully used both NiCd and NiMH batteries loose in the alkaline holder, and in rebuilt old NiCd battery packs, in my 45CL-4. There doesn't seem to be any difference in performance or recycle time with either type of battery, but NiMH give more flashes, as they are higher capacity. The normal Metz charger is ok for NiCds, but isn't the best for NiMH, which need to be charged by a peak-detection charger. When NiCd and NiMH batteries are fully charged, their voltage reaches a peak, then drops slightly, The charger detects this drop and turns off. NiCd can stand some overcharge, but NiMH will be damaged if overcharged or overheated. I charge NiMH when taken out of the alkaline holder, in a special charger designed for NiMH. In the rebuilt packs, I charge NiMH directly onto the battery contacts, which is the top when it's in the flash gun. I use a piece of circuit board with two 3mm screws to reach the contacts, connected to a NiMH charger, and a rubber band to hold it on. It sounds funny, but it works well. I recently did a wedding and used only one 900mAh NiCd pack and one 2500mAh NiMH pack, for over 2000 shots. I used the Metz 45CL-4 on a Canon 40D.

After 10 years of non-usage the capacitors in you Metz unit have become deformed- this is a common problem with electrolytic capacitors. The weaksound you observed is the unit's oscillator circuitry trying to feed the deformed capacitors. The capicitor's function, by the way, is to store the high voltage energy and release it in one strong burst of light when the unit is triggered- without capacitors, the flash tube would glow like a neon sign.

The first precaution to take is to NOT attach this unit, electronically, to you digital camera, The trigger voltage may be too high which can seriously damage your camera;s circuitry to the extent that the camera will be rendered useless and beyond repair. This can especially hold true if the flash unit has been somehow damaged because of the unit being fired with deformed capacitors.. Do theses procedures and testing by way of the flash unit's open flash button.

Try this- Start off with fresh batteries and install them in the unit. Make sure the battery terminals are clean and free of dirt, dust, corrosion are residue from leaking old batteries. If they are dirty, clean them with denatured alchacol, an ink eraser or an emery board, depending on the amount of dirt or residue.
Switch the unit on and listen for the sound- if you don't hear anything, move the batteries around and listen again for the sound- it it is intermittent, clean the battery compartment again and make sure the springs are tensioned up.

Once the sound occurs, and the light come on- DO NOT FLASH THE UNIT FOR AT LEAST AN HOUR! THEN FLASH IT AND SEE OF YOU GET A STRONG BURST OF LIGHT. Then flash it a few more times and see of the recycling times seem normal. If the recycling time is too slow, leave the unit on for a while longer and test again. You may need to replace the batteries once again for ongoing use.

If the unit does not come on at all or if it continues to only deliver a weal flash, the capacitors are probably permanently damaged. You may have damaged the charging circuit by flashing the unit with deformed capacitors.

Repairs? Unless you are a qualified and well equipped electronics technician, it is best to stay out of the innards of electronic flash equipment. Although the battery voltage is low, it is stepped up to very high voltages (at least 300 to 400 VDC) within the unit. Theses voltages can cause sever burns, nerve damage and even death if you should come in contact with them- and in some units, even after the power is turned off.

At this point in time,repair of you unit may not be cost effective but if you can't get ti going with the aforementioned test procedures you should check with you local repair facility of the unit's distributor- they MAY have a reasonable repair plan.

I hope this helps. If you get the unit going- be sure to purchase a protector that fits on the hot shoe of you DSLR to protect its circuitry when using older flash equipment. If you use manual mode on you camera or the auto flash feature on your unit- it should work perfectly well with your DSLR, Be sure to observe the camera's manual as to correct shutter speeds for proper synch. There may be a method for TTL operation with your camera- check it out with the manual and with the distributers as well. Make sure, again, tha there is no damage potential


Ed