Paul C. Buff, Inc. Technical Forum

Hello everyone,

I use a Nikon D90 + on camera flash SB-800 (as fill light) + connect with CST via PC sync cord (to trigger another flash - a Lumopro LP160 as main light).
For the first shot, the SB-800 fires and the CST triggers LP160 - everything works fine.
After the first shot, I try to adjust sb-800 but it is locked up, unresponsive, cannot even power it down.
Shooting some more, the LP160 is still working (CST still transmits signal to LP160 via sb-800) but my on camera flash SB-800 does not work any more (no more light comes out).
I have to open the battery compartment to shut it down.

Restart the same as above, except I don't turn on LP160, the problem is still the same.

Does anyone encounter such problem?
Do I have to set anything on my sb-800 to make it work?

There is a sync voltage issue going on. This can happen if the CST battery falls below a certain threshold (2.85V). It is still powerful enough to run the CST, but can cause the SB800 (and presumably the SB900) to lock up. Replacing the battery with a fresh one should allow you to do what you are attempting.

Thanks for your response.
But the Cyber Transmitter I just received from Alienbees company 3 days ago.
Should I return/exchange the new one?

Hi,

I just tested with Cyber Commander, they work just fine, no lock up occurs on my Sb-800.
So the problem probably is from CST unit that I just received from AlienBees.
Do you ship the CST with new battery? if yes then there is a problem with CST.
What should I do next?

we ship the CST's with new batteries, however, since we buy them in bulk, there is the possibility it may be lower than the 3V nominal charge. All CST's are operating when they ship with the included battery. The 2.85V specification is from our testing. However, we can not gurantee this threshold voltage is the same across all specimens of SB800's due to tolerance variations. The Cyber Commander is voltage regulated for the processor, where as the CST is not, as there is no processor, thus not needed. This regulation keeps the voltage high enough to apparently not lock up with the speedlight. The first thing i would do is test the voltage of the battery, not a bad/good test but an actual voltage test. This will tell you two things. One, what state that battery is in. Two, to tell you about teh low end threshold. If this battery is, say, 2.91V, then your threshold is different than the specimen we have. The CST was designed to operate from a camera's hotshoe or camera's PC-out terminal. Due to the design of the SB's in/out PC port design, we cannot gurantee glitch free operation in this manner, though many users do use this set up.

Hello,

I went to Fry's electronics and buy a new Energizer (good up 2018) for $3.27, changed the battery on CST, and the problem was solved.
Apparently, the battery that came with CST (inserted inside the CST) was discharged so the voltage was droped that caused the lockup in my Nikon SB-800.
I hope AlienBees would ship the new battery in its own package (may cost a little more)and customers would insert it to CST when they want to use CST.

Best Regards,

Hoang