Problems with UW Technics TTL Converter and Subtronic pro 160

Dear all,

I have problems with my brand new UW Technics TTL converter with my rather old Subtronic pro 160 flashes in my new Isotta housing for my OM-1. With the correct setting (internal switch on TTL converter to position 8), most of the time the images are too dark, sometimes black. With setting for Inon Z330 (internal switch in position 6), it works much better, but everything else than perfect. Especially when there are white parts in the picture, the flash goes crazy. But sometimes also with very easy objects. The flash is connected via an Subtronic N5 cable, on the housing end (Isotta) 2 pins are inserted in order to maintain good contacts (there are 2 spring-loaded pins in the flash bulkhead). I have to say that this cables and flashes work perfectly fine since years with my (old) OM-D E-M1 and an TTL converter from Heinrichs-Weikamp.

Whenever the images are black or almost black, I realize a VERY strong preflash - or even only one flash. Thats difficult to say. Pavel from UW Technics was very cooperative, since at least one week I am in contact with him seeking for the problem. Pavel thinks that the problem is the connection, but I can almost rule that out, I already tried 6 different cables and new pins. I believe that my flash units (purchased in 2011) may be getting old and that the flash tube, thyristor, and/or capacitor are no longer powerful enough. Subtronic is already involved in my discussions, I already got another flash from them to testing purposes - which shows the same problem (also that one is about 10 years old, however).

Further considerations and observations:

• In general I can say that the preflash is much stronger than the preflash with my Heinrichs-Weikamp converter. It looks as if the pre-flash is already discharging the flash much too strongly.

• In manual mode, the TTL converter works perfectly fine as described in the manual (setting flash strength eigher via camera or on the flash; thats really nice!)

• my Hartenberger 250 hs flashes behave the same as the subtronics (except that in position 6 of the TTL converter I have to reduce flash strength by -1 to -2)

• Subtronic is currently working on a faster software for my flashes, but I think UW technics built the TTL converter for the original Subtronics without adapted software. Therefore, it should work (at least with new flashes also without software adaptation.

• Isotta claims that TTL should work without a converter, just with the originally shipped connector to the 2 N5 bulkheads.

• The old TTL converter works even with the new camera, but I don’t see a way how to install it into the housing without losing guarantee (soldering necessary) and furthermore, I would not have the option to switch between TTL and manual any more (in my old housing, there was an additional switch which disconnected one line of the TTL converter to the bulkheads to switch from TTL to manual during the dive)

My problem now is that I have no idea which parts to exchange: TTL Converter? Flashes (renew the internal electronics means about € 400 per flash)? No guarantee that it works after investing in renewing the electronics of the flashes or even getting new ones.

Any ideas are welcome,

Jens