What would cause my LED boards to stop working? I have two boards that seem to be the problem. I have six total boards and four of them work great together. Two other ones when I plug in to play with the other four cause everything to stop working. The led light on the power supply begins to flash. What causes this problem. Also I have one board that has five LED's that always stay on. Your insight is greatly appreciated.

The big question is, "did those other two ever work?"

If those two boards have *never* worked, then there are a number of things that could have gone wrong in the construction process-- what you've got is effectively a short circuit-- the light on the power supply indicates this.

If, however they *stopped working* as your question implies, then it's most likely that the chips on the board have been damaged and need to be replaced. This can happen very easily if the boards are plugged in wrong, even once. The most common ways for this to happen are if they are plugged into an inappropriate power supply or-- in your case since your power supply is good --plugged into neighboring panels with the 8-pin connector misaligned ("off by one pin" ). It's *much* better to unplug the set of panels and plug them all in, and check that the connectors are straight before applying power.

On the bright side, the chips are not expensive and if you've built the boards with the sockets, they're even easy to replace.

On the board with the five LEDs always on, can you describe a little more clearly what you're seeing?

The panels all individually worked. I had all six panels on and working all at once. I then undid the panels to move them and reconnected them and that is when I had issues. All of my soder points look fine from what I can see. Where should I start to trouble shoot my problem?

You have a short circuit on those boards-- the behavior indicates this pretty clearly. Unless you've got a wire or blob of solder physically connecting the +24 V line to ground, then by far the most likely cause is that the chips have been blown. There are *very* few ways that this can happen. Since both boards went out at once, it certainly sounds the last two had power applied when they were misconnected.

To verify that this is the problem, first mark all four chips on one of the damaged boards with a pencil, so that you'll know which chip was from this board. Then, *carefully* remove all four chips from their sockets, ideally by using a tiny flathead screwdriver. Slide it all the way under the full chip, and lift it gently, all at once. Do not pry the chips out, and do not use excessive force. Make sure to remove all of them.

Then, install a working chip in quadrant 1 (and optionally in the other three quadrants, but *at least* in quadrant 1). You may have a spare in your kit, or you can borrow one from another board. Then, connect that board to your board with the power connector-- being sure to align it correctly --before applying power.

No matter which input or output I use when I plug in the damaged board it shuts down the four good boards and the power supply light begins to flash. I do not have any spare chips to try testing them with the board. Do you sell them on your website?

No matter which input or output I use when I plug in the damaged board it shuts down the four good boards and the power supply light begins to flash. I do not have any spare chips to try testing them with the board. Do you sell them on your website?

DO NOT apply power to the damaged board in any way while those any of those chips are still on there. In case I didn't say this clearly enough before, you *need* to remove all four damaged chips. Nothing will work until you do so. It is potentially hazardous to any other boards that you connect to it while it is still in this state as well. Your short circuit, even detected by the power supply, should be a clear sign that you are doing something wrong.

My suggestion was to test out the board-- with good chips, which you could borrow from the other boards. (If you do have other boards that are working, it seems likely that you have good chips on those boards.)

The chips that you need are type LM324 quad op-amps; you can get them from various electronics distributors, or we do have a "repair kit" for sale on our web store, in the garage sale section.

i picked up a couple of extra ic chips. can i completley remove all of the chips from the bad board and place one chip in at a time and fire up the board to ensure that each chip is functioning correctly? will the one quadrant that the chip is in work correctly without the other chips being installed? once the first chip is confirmed to be working correctly can i then install the next one and so on and so fourth to test to make sure each quadrant is working?

>can i completley remove all of the chips from the bad board

Yes, as I said before, you need to do this.

>and place one chip in at a time and fire up the board to ensure that each chip is functioning correctly? will the one quadrant that the chip is in work correctly without the other chips being installed?

As I said before, you need to have a chip in quadrant 1 for the board. If you want to test the chips, put them in quadrant 1, one at a time. If you want to test the quadrants, put a chip in quadrant 1 and then in 2, 3, or 4 as well.

Ok so i replaced the chips with new ones. Now I have this happening. What does it mean when I have ten solid led's in a quadrant? Its like that for the first three quadrants and the last quadrant has just five led's one. The ten leds that are on are the same ten led in each quadrant. Sorry for all of the questions just having lots of problems and dont want to give up on this project.

It sounds like something has gone wrong that is causing all four quadrants to operate at the wrong "zero" point-- that it doesn't idle correctly. Double-check the values of R115 and R116, and make sure that both solder connections on those two resistors are clean, shiny and wet. The problem is very likely to be at one of those two locations.

There's probably also a separate issue causing half of the LEDs to not light in quadrant 4. It's probably a poor solder joint on one of the five LEDs that *should* be lit to be consistent with the other quadrants. If you like, you can leave that one alone until the bigger problem is solved.