fullerlee, it is unclear whether the chatter is associated with a particular solenoid or all of them. If it is with one only, then substituting another will tell you if it is a 'solenoid' problem or a current supply problem. If it happens to all of the solenoids, then it is a problem with current from the clock. If it happens on one valve only, regardless of the solenoid, then the problem may be narrowed down if you wire the zone to a spare terminal in the clock (if one is available). If a spare is not available, wire the zone to an existing terminal and see if the problem goes away. If it does not, the problem most likely exists in the zone wire itself.

Hi Lee
I just went through the same nightmare ....
In my case it was the very expensive Rd 900 that is fried
I checked both the solenoid and the other parts of the valve. This Rd 900 is about 8 yrs old but has had a very easy life. Sadly I had a feeling something was a bit off. When I would change the zones with that crappy dial, the LCD would display other zone times and it couldn't seem find its proper place. I am really kind of bummed as this controller runs around 180+ dollars. I am sure this is your problem because I was getting the same clicking on all the valves. I hope this link below will help you
Kind regards
Ed

Here is a link that might be useful: Troubleshooting irrigation valves

I also have solenoid chatter. Started a month ago. It's on all circuits. When I check the controller module, I find the gate signal going to the triacs to be faulty. Instead of this being pulled low (to turn on a circuit) it jumps around (measures .5-1.75 volts) causing the triacs to go on and off (causing the chatter). I'd like to put a scope on it to see exactly what's happening but don't have one. Does anyone have any idea what might be wrong? I have not been able to find the details on this cpu (S3C7C48E70-QWR8) so I don't know what is driving the output pin(s).

I had the chatter issue on my RD900 after about 10 years. The voltage from the transformer was 25v but the output to the solenoids was 12-14v pulsing about twice per second. I called Irritrol (Toro) and they quoted me a maximum of $65 to repair it. I sent in the module and circuit board and got a call in two days saying it was done. Unfortunately, the service department said it was a flat rate of $85.

The tech there said that a marginal solenoid could cause the triac to blow and told me that they should be tested yearly. He said to run a solenoid for about 10 minutes to bring it up to temperature, then when it goes off, test the resistance at the controller terminals. Should be between 15-50 ohms to be in spec. If not, replace the solenoid.

I have an RD1200 controller it has been working for about 7 years. All of sudden all solenoid valves started to chatter. But timer indicator seems normal, clock running normal. Replaced 9 vac battery any way and no change. I put system into manual control testing one output at a time. I put an AC voltmeter measuring an output terminal to common wire. On one terminal I got 13 volts and I expected around 24. I checked transformer input it was at 26 vac. I had another circuit where sprinklers were pulsing with a period of about 1 second between pulses of water and that terminal voltage would cycle every second between 9 vac and 0.5 vac. I removed digital electronic portion fromm unit detaching ribbon cable. So I am operating sprinklers by applying 24 ac directly to each solenoid with clip leads and all solenoids work
fine no chatter and sprinklers turn on.
The digital controller keeps time perfectly, it cycles through program as defined. I think the output Triacs switching the 24 ac are not functioning.
Does anyone have a circuit diagram for the output board?

Hi,
Just fixed my Rain Dial RD900 With the chattering solenoid problem with the capacitor fix from ccalkins

This post was edited by Rickinphoenixaz on Sun, Apr 27, 14 at 19:35

I just fixed my RD-900 for $13.00 and one hour of time all my problems are now gone from chatter to display issues and in some cases the sprinklers not coming on. I followed ccalkins post from Fri, Jun 14, 13 at 11:12

I just had a second RD1200 fail with chattering solenoids (all circuits). I took the unit apart (carefully) and checked voltages. I found 25vac on the + side of capacitor C5 (220uf) instead of plain DC. Replaced this with a new one ($1.5 at Radio Shack) and it is working fine now. Thought I would let people know...

It cost me $13 because I had to purchase a soldering iron as well.

The capacitor change worked like a charm on my RD-900 - thanks for posting this info!

The capacitor fix worked perfectly on my RD1200. The module was from the year 2000 and would have cost me $$$ to replace. I already have a soldering iron so my total out of pocket was $1.61, tax included. Thanks usamikeg!

hello everyone. i have the same problem and would like to fix it but i don't know how to do this - "I found 25vac on the + side of capacitor C5 (220uf) instead of plain DC." i have a multimeter but never used it. can someone give me the basic steps to check the voltage (or whatever) and replace the capacitor? any help would be greatly appreciated!

Pnutbutterdog, I also dont know how to test a capacitor so I just went ahead and replaced the capacitor on my controller. The problems described by others were exactly the same as mine so I didn't waste time tying to verfy the capacitor in mine was the problem, which it was. To replace the capacitor I just heated up the solder where the capacitor wire goes thru the board while pulling firmly on that end of the capacitor until the wire came out. Then again on the other side. It was very easy. I did the opposite with the new one and never even added any solder. Just heat it up and insert the wire. Worked perfectly for me. Hope this helps.

Forgot to mention one thing. The capacitors are directional, and there are arrows one both the old and new ones. So be sure to replace in the correct direction.

Having same issue bought the capacitor but have no idea where c5 is any help or insight? My capacitors are labelled mov on my rd900.

thanks jdbnapa. i'm going to try like you without testing it. now i'm not even positive which one it is on the board but i found something with a c5 next to it and it looks like this (except its black and probably the biggest component on the board.)
http://comingsoon.radioshack.com/220uf-35v-20-axial-lead-electrolytic-capacitor/2721017.html#.VZM0DkYeqcs

i hope this is the right one...i'm off to radioshack to buy it. hopefully they know if its the right one or not.

on your comment on the direction, i dont know what you mean by arrows for old and new ones? i'm just going to put it in the same way the one thats in their now is. one side is definately different from the other.

proudmamma - i have an rd900 and i dont know what you mean by labelled mov? i'll tell you where i found mine if everything works out.

I was having issues with my rd1200 irrigation dial , my sprinklers head with pop up for about 3 second on every station and then it would quite .. Also I try to run stations manual and would not work .. So I finally took it apart pull the board out from behind controller and found out that my capacitor that seats on c5 .. Was not working . I tested with ohm meter and didn't get any readings /resistance. Went to radio shack and replaced capacitor # 235uf . Now sprinkler system works like a dream . It only cost me $1.49 and about 1 hour of my time

I was having the same problem with my irritrol RD900. The symptoms were, output to the valves were between 5 and 15 volts AC when they should have been 24. The power supply checked out OK at 24 volts AC. Most station outputs held steady at those voltages, some fluctuated at the rate of about 1 per second. Also when I would turn on a station manually, the screen would flash on and off for a couple of seconds. I am an electronic technician, so its no big deal to replace a capacitor. I read that replacing capacitor X5 would fix the problem, but was leary that it would work. I had tested that cap with an ohmeter, an there was some capacitance. An ohmeter wont tell you how much, just if its open, shorted or has capacitance. I replaced it with an exact replacement (220UF 35V), and voila, it worked. Output voltage was back up to 24 on all stations, no fluctuations, no screen flashing. Good luck finding the cap at Radio Shack. Some of the larger Radio Shacks may have a good selection of caps, but the one by me did not. I bought some off of eBay. I had to buy a 5 pack, and with shipping it cost 6.50. Still pretty cheap. If you cant find a 220UF 35v cap you can go up in values 10 or 15 percent and be OK. If you don't know where cap X5 is on your control, it's inside the black box that removes from the main control box. No need to power down. Pull the ribbon cable from the main box, and pull the black box out of its hinges, remove the battery, remove the back of the black box by placing a flat bladed screwdriver into the three slots on either side of the box and twisting, remove the 2 screws and pry it away from the circular selector switch. Cap C5 is on the underside of the board, and is the biggest component on the board. Mine was black. When buying a new cap, make sure it is a polarized electrolytic. When replacing, make sure it is put in exactly the same as the old one. There is a plus and a minus on them. Do not touch anything on the board you don't need to, or there is a possibility of ruining the board due to electrostatic discharge. If your soldering skills are not good, get some help, or practice first. Don't use over a 25 watt soldering iron. Hoped this helped.

You were so right. I couldn't narrow it down because i had 1.2.4 valves working and 3 wouldn't. 3 and 4 had same voltages. 13vac and all over the place. I went to Frys Electronic and bought a cap for 1.49 but it was radial instead of axial. So i put ferrite beads on leads because they were so long. Fit and works great. 26 vac across all 4 valves now. And no floating voltage. Thank you! I just knew i was going to did up the valve and it is AZ summer. Thanks also for jumper idea. That test proved valve was good. And they want $85 to fix it. Rip off.

I find this Irrigation Solenoid performance is very good! www.irririchvalve.com

Does anyone have water hammer, even when the valves all working correctly? I have tried changing pipe sizes, made them all the same size, 3/4, and still it hammers. I do have a 1"valve reduced down to 3/4, but I am told this is common. I have a front yard circuit, that does not hammer, and a back yard circuit that does hammer. Any ideas?

The 220uf, 35V capacitor replacement works again! Awesome debug job to whomever initiated the first repair!

Thanks for this thread. I have the same chattering valve problem and checked the voltage in my controller and it fluctuates. Opened my case (the tabs were are pain to remove - broke 3 but okay as th other 3 remained.) My circuit board seems a newer model. The c5 is part of the circuit board and seems unreplaceable. There is a C7B capacitor (220uf50v) Not sure if the C7B is causing the problem or something else that is repairable? C7B does not look swollen. The 2nd picture is the old board with the C5 capacitor that is replaceable - got this picture from the web. Any suggestions?

I just repaired the RD1200-EXT at my rental house by replacing C5. A few people have mentioned higher voltage/capacitance ratings, so I'll add this: the original capacitors (at least in my case) were not made by one of the mainstream manufacturers, and are rated at 85 degrees. When replacing them, try to find 105 degree rated capacitors; they use better electrolyte and will last longer regardless of manufacturer. This is important because these timers run 24/7 for years. If Irritrol had used quality 105 caps to begin with, this discussion probably wouldn't exist!