Paul C. Buff, Inc. Technical Forum

Preface: I run two Einsteins and one AB400 off a Cyber Commander (Canon 40D). All lighting purchased in March (or April) 2011. The AB 400 uses a CRSB+. The Einsteins each use a CSXCV.

E1 = Freq1/Ch1 ...first in a 36/32 softbox, then in a PCB white beauty dish socked.
E2 = Freq1/Ch2 ...64" PCB PLM socked.
AB400 = Freq1/Ch3 ...7" reflector 30deg grid, later w/red gel no grid.

NOTE: The issues below occurred immediately after changing the softbox to the BD and gelling the AB400.

Here we go...
I was in the middle of a shoot and lost control of the AB400. I had just put a red gel on and went back to meter and shoot. The modeling lamp went off and it wouldn't respond to the CC or manual press of the test button at all. The lights were still lit on the back of the unit. Turn it off and on and it worked fine from there on out. No more issues this day.

A few minutes later the same thing happened to E1, which I had just changed from a softbox to a BD. I really noticed this because E1 was my main and I run the modeling lamp full power to shrink pupils. So the modeling lamp went off and the unit would not respond. It would beep after pressing for a test pop from the CC, but no light. The unit was obviously on, looking at the screen on the back. After about a minute or so the modeling lamp would just come back on and would work fine. Then I would shoot for a few more minutes and back off it goes. I tried power cycling at the unit, but it would still have to wait for some period of minutes to go back to a working state.

This was embarrassing and frustrating to deal with in front of a customer :(

E2 had no issues.

Any clues?

EDIT: The entire shoot lasted about 1 hour total. So the lights were on for about 1 hour.

For the B400, were you using a CSRB+ or CSR+, and when you switched it off, was that from the switch or from the power supply?

As for the Einstein, that sounds like the thermal cut off is activating. How was the light oriented? How fast were you firing and at what power? What was the ambient temperature (approximately)?

B400 using CSRB+. I switched it off with the switch on the back of the light after noticing the issue and trying to see if the test button on the back of the light would operate.

The light had a BCP socked white beauty dish on it angled down at around 45 degrees.
I was firing at around 1 shot every 2 to 4 seconds, often longer, at less than half power, maybe even closer to 1/4. I can check it when I get home this evening because it was left at that power.
Ambient temp was probably around 85 degrees (Friday evening, 6pm EDT, Atlanta, Georgia, in my garage with garage door open).

I DID have the modeling lamp running at full power.

With the rather warm ambient temperature and a relatively confined space (especially if you used the lights deflector) for the modeling lamp, which was at full, it appears the thermal cutoff was activating on the E640. You can ease the heat output by reducing or shutting off the model lamp output.

As for the B400, you said the lights were still on the back. Specifically, which lights?

It was in hair light position so it was rather high. I could not see exactly which lights were lit on the back, but surely there was a light lit back there. I know that doesn't help much.

I do remember this; Where the little light on the CSRB+ usually shines green, I think it was red. This may be normal, but I just noticed it. The only reason it struck me was that when I shut down I usually unplug the CSRB+ (that has the B400 on the other end of it) and the green light goes out. Not sure under what conditions it goes from green to red though.


I will keep an eye on that Einstein, and watch for future possible high temp. conditions.
I guess the beauty dish IS a more confined space, and with the modeling lamp at full it may have gotten pretty hot in there.

A constant red on the CSR+ is indicative of a low voltage lock up, and is rather rare. Recycling power should restore it to working.

Thank you!