I purchased a 6V 300mA Power Adapter (273-1758) from Radio Shack to use with my B-BBL Programmable Message Light, but the unit keeps shutting off. It works fine if I keep it on the default "HELLO" setting, but it shuts off if I use the clock or memory functions. The time it takes to shut off varies from a few seconds to a few minutes. The "H" adaptaplug (273-1711) does stick out a little, but it is pushed in all the way, and the fit is secure. I have since tested out a second message light, as well as a second power adapter (same make and model), and the same thing happens. The unit works perfectly (in all modes) if I use batteries, but the batteries don't last long enough to make the clock practical. The instruction manual specifically states not to use rechargeable batteries.
If anybody has suggestions, I'd really like to hear them. I really like using it for a clock, but I'll probably stop after I go through few more batteries.
Do you know how much power it is actually using? My guess is the power supply isn't putting out enough power and the unit is switching off. If you can't meter the voltage while the unit is running or the power draw in mA I would suggest getting a 1000mA 6v power supply and see if that does the trick.
OR, maybe the power supply is actually putting out to high of a voltage and is causing the unit to shut down.
This unit "prefers" a current of 125-150mA.-as in the specs. I've done a lot of expermenting myself with the same unit and found that the unit works just fine on the 4.5v setting of an adjustable wall wart. Most of the warts put out considerably more voltage than what the switch setting indicates-even under a light load-like 100mA [img]images/icons/tongue.gif[/img]
(I'm using a Recoton wart that offers a choice of 100mA and 300mA as well as 3v, 4.5v,6v., 7.5, 9v etc)...
I ran the unit OK on the "6v." output-which really reads unloaded 7.8v on a DMM, but decided to use the 4.5v. setting because it really came out to almost 6v. with a 100mA load.
When I ran the unit on the 300mA setting and "6v." (actually 7.8V), occasionally the unit would shut down when changing from message to the clock function!
-So that's why I now run it more conservatively at the lower settings, and have experienced no more strange display artifacts or shutdown.-And it's still plenty BRIGHT.
I've been using the same Rat Shack 6v 300mA adapter with adapt-a-plug "H" for the last few weeks and haven't had any problems. The sign is on 24/7. Usually, a custom message runs, sometimes I run the clock.
Yours may be a bit more voltage sensitive. Find a 4.5v wall wart and I bet the shutdowns will stop.
I think the problem is an overvoltage condition as mentioned; the message light just shuts down when the input voltage gets above a certain point. Like Doug said, those power adapters aren't regulated to a precise voltage, but instead rely on the load to drop it to the rated voltage.
It may be a combination of a slightly higher output on your adapter and a lower cutoff voltage on your message light.
I've been using a 5V supply I had left over from a powered USB hub, which coincidentally had the exact plug and polarity I needed, no problems.