Relays Don't Activate - Enable Issue


#1

Hello - I recently purchased a 16-relay board - ZADSR161DPDTPROXR. When I send in a command I see the LED bar graph go active but no relays pick. After a little probing it looks like pin 9 on either of the TPIC6B595 registers might be floating or not driven properly. I probed with my DMM and when I set to measure volts and touch pin 9 (either '595 or pin 5 of the PIC) relative to GND the relays suddenly activate. I’m thinking it might be a defective output on the PIC because it does appear to be connected (and GND is connected, too). If there are any tips on how to repair this I’m all ears. I bought a bunch of these cards and this is the only one that exhibits this problem.

Thanks,
Keith


#2

I soldered a 10K resistor to pin 9 of one of the '595 registers and it seems to work now. Fingers crossed!

Keith


#3

Hi Keith,
I’m not sure how this could happen, but I’m glad to hear you have a resolution, please let us know if we can help with anything.
Thanks,
Ryan