Power issue with MAX7219?

Zeus

Hello All,

I am using a MAX7219 to drive a 4 digit display and I believe that I have a power issue which results in the going blank after only a few minutes of use. The program (clock) continues to run however I have no display. I believe that I have a power issue as the display seems to shut down only when it is asked to drive too many segments, ie 1:11 is no problem however 12:58 is. The other reason that I think that this is a power issue is that the voltage regulator on my BS2sx get very hot, the only thing that does not seem to fit is that when I use a BS2 it's voltage regulator does not overheat yet the display still blanks out. I have tried multiple stamps, displays and MAX7219 chips.

Does anyone have an idea as to what I am missing?

Also, I am using a Professional Development Board and from what I understand this should bypass the Basic Stamps voltage regulator and utilize the PDB's onboard voltage regulator instead.

Zeus

Mike Green

How do you have things connected? Obviously, you're drawing too much power through the Stamp's regulator, but, without a schematic, it's nearly impossible to tell you why or how.

Zeus

Thanks for the Reply Mike,

Here is a working schematic, obviously ignore everything on the rightmost side as I am using the Professional Development Board right now.

Zeus

Mike Green

I can't see how the regulator on the BS2sx can get hot based on your schematic. There's no power going to it. Either the schematic doesn't reflect the actual connections on your board (most likely) or there's something wrong with the BS2sx (possible, but unlikely). There's nothing wrong with the part of the schematic on the left side involving the BS2sx and the MAX7219.

Zeus

Mike,

I was wondering if it could be the BS2sx myself because when I revert back to a BS2 the BS2 regulator does not seem to generate any heat, however the display still drops out.

Zeus

Chris Savage

I would recommend posting a high-resolution photo of your exact board showing the connections.