Need help troubleshooting the Castle Multi Gate

I recently put together a Castle Multi Gate, and I am having an issue of not receiving a signal out of the XNOR output. I will include a photo of the pcb. I checked the points with a multimeter and seem to be getting a normal connection. I receive normal output gates out of the other 5 outputs, just the XNOR I am receiving nothing. Thanks


The problem is somewhere in this XNOR region, as the XOR is working fine. im thinking maybe a faulty resistor? as U3 and U6 are working for the XOR.

can you post a pic of the back of the PCB too?

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got a few ideas for you:

  • U2 looks to have two (or possibly all 3) legs bridged
  • lots of little balls of solder are hiding in the flux all over the place. would definitely be a good idea to give the board a good cleaning with a toothbrush and some isopropyl alcohol to sort out any possible shorts

everything else checks out - resistor values are correct, diodes, ICs, regulator and e-caps all have correct facing and solder joints look good across the board :+1:


thanks for the tips, I cleaned the board too. So I fixed the problem. The IC on U6, pins 6 and 7 were not inserted into their chip socket correctly and folded in on themselves. I am getting signal from the XNOR now and the other outputs too. everything is good and the module is 100% working. thanks for taking the time to help me with my problem. cheers.


glad you solved it! enjoy!

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I’ve been waiting for this to be resolved before I posted some silliness


Is that the middle IC of the 3x 14 pin ICs? It’d take laser eyes to see that from the first photo but good to keep in mind just in case of future issues when sockets are used.

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