[nigelpritchard]

I have just checked my old AF400FTZ and after fitting batteries and switching on, the charging light initially came on (I heard the charging sound) and then it went off and now will do nothing. Tried svereal sets of batteries to no avail. I also managed to attach an external 6V bench Power Supply (PSU), but still no luck (it draws about 70mA from the PSU) I assume a failure in the high voltage inverter or such?

Does anyone have a schematic diagram of this unit?

[Alex645]

I have just checked my old AF400FTZ and after fitting batteries and switching on, the charging light initially came on (I heard the charging sound) and then it went off and now will do nothing. Tried svereal sets of batteries to no avail. I also managed to attach an external 6V bench Power Supply (PSU), but still no luck (it draws about 70mA from the PSU) I assume a failure in the high voltage inverter or such?

Does anyone have a schematic diagram of this unit?

Sorry, I don't have a schematic for the AF400FTZ. It sounds like the thyristor or the capacitor has failed or there is an internal short. Flash units don't do well sitting for long periods without use.

If you take it apart, just be very careful not to get shocked from the capacitor. I've been zapped taking apart lesser flasher unit.

[Lowell Goudge]

It may be the capacitor itself has failed. Electrolytic capacitors “form down” if there is not voltage applied,

This is why it takes so long to charge a flash that has not been used for a while, until the oxide layer rebuilds itself with voltage applied the leakage current stops it from charging fully. In the extreme it results in a short circuit.

[nigelpritchard]

Thanks for the feedback guys. I'm guessing the capacitor (and thyristor) is inside the swivel head unit since I don't see it in the main body; haven't yet worked out how to get inside the swivel head unit, unless I have to have the whole unit in pieces. The most obvious screws don't enable dis-assembly of the head.