Malfunctioning Fusion Relay board

I just received a relay board with a Fusion controller and two FXR24xDPDT relay boards (connected via the FXR expansion port)

I received this order yesterday. During testing today I am experiencing some strange behavior out of one group of relays. Relays 1-4 of bank 2 are not switching on properly. When activating any single relay out of the group of 4 it it will turn on (albiet with a much weaker click than any of the other relays). When turning on a second relay in this group, the first relay activated will turn off, and the second will not turn on.

With a single relay activated in this group the voltage across the coil is 3.3V When a second relay is activated the voltage across the first coil drops to 1.4V and the relay turns off, and the second relay never turns on, with a voltage at the coil of only 1.4V.

Additionally, the indicators for the group of 4 relays is brighter that all the rest when off. And when one relay out of this group is activated all 4 LEDs of this are illuminated.

It seems as though there is an issue with the driver circuitry for these 4 relays. All other 44 relays seem to be working as expected thus far. Any thoughts?



It’s hard to say exactly what is causing that issue. The relays are driven by TPIC6B595 drivers(they are large surface mount chips on the relay controller. These drivers operate groups of 8 relays so if the issue is only seen on 4 of the relays then I would say the driver is not the problem. The only thing I can think of that groups relays in 4 is the surface mount resistor networks which drive the LEDs(they consist of 4 resistors), that however should not affect the operation of the relays. You could carefully inspect these resistor networks on the board to see if one of them seems to be “a bit off”.

When you are testing the relay coil voltage are you actually doing it on the relay coil pins? 3.3V is really low, those relays should be driven by 12VDC.

One thing you could also check is your power supply. It should be a regulated 12VDC power supply. The board itself will draw around 150mA at 12VDC with all relays off. Each energized relay will draw approximately 30mA. If you are using the 1.25 amp 12VDC power supply we provide then this means you can turn on up to around 36 relays at one time, but if you try to turn on more than that you will exceed the power supply’s current draw limit and the relays will turn off.

Conclusion: I would recommend sending the board in for warranty repair.

Thank you,
Travis Elliott


I ended up purchasing a new board, and I am back onsite at this project trouble shooting a few issues.

Several of the relays response time is very slow, up to a second or more in some cases. The board seems to be executing the command on time, the indicators led for that relay lights almost immediately, but the actual coil is late to activate.

Any thoughts?

Furthermore, the channels that have this issue seem to get better with “exercise”. Once you get the relay engaged, it responds quickly if you keep cycling it. After it sits for a little while (less than a minute) its gets “stuck” again.