Author Topic: Solved - an MR16 setup somewhere and a Bobcat Tester, can you try this?  (Read 1287 times)

Offline JonB256

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I ran into an odd behavior today while testing.

My first test was with an MR-16.

I have a 12 channel RGB Mega tree star (4 RGB dumb strings) and got it wired up yesterday.
To verify that all is working, I connected my Bobcat DMX tester to it.
It went RGB RGB RGB RGB as expected. Great

But, I wanted to "burn it in" a little plus see how bright it would be.
I put it on ALL channels, then switched to Intensity.
It began flashing rather than solid on (white) at 255. Thinking I had it set on Pulse, I checked.
Nope. 255. I dialed it down lower. It became perfectly stable at 120 (I dialed pretty fast).
I took it back up slowly and at 170 it began flashing again. Dialing down slowly, it went solid at 165.

Is this normal?

So, I tried it with strings hooked up to a D-Light DC 16 channel DMX board.
It did the same thing, but oddly, the break point was closer to 140 instead of 170.
The D-Light board showed clear indication that the PIC chip was actually Rebooting (i.e., the DC16 DMX Firmware will flash its start channel on power-up before locking into the signal. My board was set as 17, so it flashed once, paused, flashed seven times, then the Lights went on, then went off. It repeated that cycle indefinitely)

So, if you have a Bobcat DMX tester and ANY DMX boards hooked up that you could test, could you try putting it on ALL channels, then see if you can dial the intensity all the way up?

AND THE ANSWER IS !!

My Dumb RGB lights (200 nodes) pull almost 12 amps!!! Full on was drawing so much current that my power supply voltage was dropping below 5 volts and the PIC would quit. Then lights would go off, then the voltage would come up, the PIC would reboot, then repeat.

My original power supply can only supply 4 amps on a good day.  <md..

I may have to use a commercial design Power Supply just to light up my star.
Though it is BRIGHT when fully lit.

Thanks.  Jon
« Last Edit: October 07, 2012, by JonB256 »

Offline rm357

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Make sure your power supply is big enough to run all of your lights plus a little. The 7805 on the mr16 will turn off if the voltage drops much below about 7 volts... Also make sure the wire is big enough to carry the current...
Robert
Warner Robins, Georgia, USA

Offline JonB256

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Warner, I woke up a midnight last night with that same thought. Wire size isn't the problem (18 gauge). It must be the power supply. It is a 45watt brick and my load is about 40watts (I thought). I'll test again using a SS Hub for power after it warms up a bit. Dark and cold right now. Cold for Texas (50F), that is.