- This topic is empty.
September 21, 2013 at 5:29 pm #22646
Just completed my build and everything looked perfect. Booted up connected to the network with DHCP and got I.P. address 192.168.1.3. I took note of the MAC address and powered down. I added the MAC to my router so it could automatically assign an I.P. based on the MAC. When I powered the unit back on it flickered once and then went lights out. I went back and checked for DC voltage again and had nothing. I have read other posts so I measured the VIN to GND resistance. It was only a couple OHMs. After removing the Zener Diode the resistance went up to 29 OHMs. I then proceeded to remove D2 & D3. The resistance between VIN and GND remains at 29 OHMs. I done a very close scan of the board and noticed I had failed to solder 4 of the pins (the ones near the edge of the board). I am assuming that this is what caused the failure. I have corrected the soldering issue. Currently I have all of the I.C. chips removed with exception of IC1 as well as all 3 Diodes. Not sure what to try next.
Imnee.September 22, 2013 at 8:48 am #25567
Can you be more specific about the ‘4 of the pins near the edge of the board’? What component(s) do these four pins correspond to? Try to remove IC1 as well and see if that changes the VIN to GND resistance.September 22, 2013 at 1:47 pm #25568
I removed IC1 and VIN to GND is now a very high resistance. The pins I missed were on the RJ45 connector. They are highlighted in the following attachment.
ImneeSeptember 22, 2013 at 4:26 pm #25569
Resistance is 1.2 M OHM.September 25, 2013 at 1:00 am #25570
The four pins on the RJ45 jack shouldn’t be the problem — they are for the two LEDs on the RJ45 jack, so not connecting them merely causes the LEDs to remain off and shouldn’t matter with the power circuitry. Since your VIN to GND resistance is still very low (29 ohm as you described), it suggests that there is still a shorting / damage somewhere on the VIN line. Try yo remove IC1 and see if that changes anything.September 25, 2013 at 1:34 am #25571
After removing IC1 VIN to GND is now 1.2MOhm.September 26, 2013 at 5:03 pm #25572
Looks like IC1 is damaged and needs to be replaced. Make sure your sprinkler transformer’s output is no more than 28V AC as that will likely to exceed the limit of IC1. Keep me updated if the issue has been fixed. Thanks.September 26, 2013 at 6:20 pm #25573
OK, my voltage is high then. It measured to be 28.6. From the warning below I figured I was under the wire. I will replace IC1 and get a new transformer and post the results. Thanks for the help.
Important: use a multimeter to measure the AC voltage between the two transformer wires. Make sure it’s no more than 29VAC.September 26, 2013 at 6:24 pm #25574
28.6 should be fine. So I would suggest replacing IC1 first and replace the transformer later if necessary.October 3, 2013 at 12:52 am #25575
I replaced IC1 and put all of the diodes back in the circuit and as before the voltages looked good. I replaced all of the remaining IC’s and now everything is working well. Still not sure what the root cause of the failure was. Maybe a bad component? Thanks for the help debugging!
- You must be logged in to reply to this topic.