Help IDing Caps on Gate Opener Timing Board

Thread Starter

Art Duino

Joined Nov 30, 2017
52
I have a gate opener that was probably installed in 2000. Because of new safety regulations (supposedly), the manufacturer does not support it now. Odd, since things like electric eyes and safety loops can be installed pretty easily.

The opener has a keypad outside the gate, one-button remotes that work via RF, an on-off toggle switch on the cabinet that will cause the gate to stay open, a momentary switch on the cabinet which appears to do what a remote does, and a sensor in the ground that detects vehicles trying to leave the property. The momentary switch looks bad, and I never use it, so I plan to disconnect it until I can replace it. It doesn't function.

When the keypad, ground sensor, or a remote is used, the gate is supposed to open, remain open up to 60 seconds, and close. The opener has a main board and a timing board which connects to the main board. The timing board is a Falcon ACTW3C, which is not made any more. It has a pot on it to adjust the stay-open time from 0-60 seconds.

The gate has had some issues. It has refused to respond to the ground sensor from time to time. This may be related to rain, but I'm not sure. I can't replicate it. It also likes to adjust the opening time down to nearly nothing, even when the pot is not moved. Twiddling the pot again restores the opening time.

The pot tests out okay at 0-1M ohms.

I am guessing the timing board is the reason the stay-open time shifts. I am not sure. The sensor problem could possibly be unrelated. I have been checking the components to see if anything is fried. I went through the gate opener and cleaned all the connections I could without taking it completely apart.

The electrolytics work. It also has three caps that may be ceramic. I can't figure out what they are. They are identical. They are labeled VF050560 TK.

The timing board also has an IC. It's an HD74HC14P, which is a Schmitt trigger hex inverter.

I am wondering if the caps or the IC are fading. The caps appear to be identical, but they give me a wide variation when I put a meter on them. Like 200-800 uF.

I would like to make this thing work and save about $1300. Can anyone tell me what kind of caps I have? I can't find them on the web. They are yellow and shiny. I figure I can replace them for almost nothing and see what happens. The IC is very cheap, so I may as well stick a new one in there.

I have no schematics. Can't find them. I contacted Falcon Electronics to see if they can help me get one.

powermaster timing board falcon cap.jpg

powermaster timing board falcon.jpg
 

Papabravo

Joined Feb 24, 2006
21,261
IMHO, your strategy is unlikely to prove successful. Replacing electrolytic capacitors is sometime helpful because they have a semi-liquid paste for the electrolyte. The capacitors on your board are ceramic which have a solid dielectric and have a much longer service life. The integrated circuit is unlikely to have failed from any age related effects.

The one thing which might be helpful is to examine the soldering job on both sides of the board and redo any that appear to be subpar. There is a risk in doing this that you will destroy the board beyond repair if you are not experienced in board repair. The 74HC14 is a CMOS part and so you should take statice electricity precautions in handling or working on the board. An unintentional static discharge could render the board useless.

Lastly, since this is a double-sided board, you should be able to reverse engineer a schematic. It won't be quick or easy, but it is possible.
 

Thread Starter

Art Duino

Joined Nov 30, 2017
52
Thank you for the help.

The back of the board looks great, and I can't find any burn marks or corrosion.

The electrolytics test out fine, so I am not concerned about them yet.

Why would the ceramics test out so differently if they haven't failed?

I just took the momentary switch off, and the contact on the rear of the button is steel, which is an odd choice. It's mostly rust now. I would guess closing it in its current state does nothing at all.
 

MisterBill2

Joined Jan 23, 2018
18,975
I suggest replacing the timing adjust potentiometers, because they are the device that is most likely to be intermittent. Depending on how they are connected, replacing them with a resistor might also be the way to go. I also suggest cleaning the PCB with alcohol and a small brush, in case a conductive coating is the problem. Assorted vapors condensing on a board can cause strange malfunctions is what I have learned over the years. And that board does not look perfectly clean.
 

MaxHeadRoom

Joined Jul 18, 2013
28,767
The electrolytics work. It also has three caps that may be ceramic. I can't figure out what they are. They are identical. They are labeled VF050560 TK.
I am wondering if the caps or the IC are fading. The caps appear to be identical, but they give me a wide variation when I put a meter on them. Like 200-800 uF.
Can anyone tell me what kind of caps I have? I can't find them on the web. They are yellow and shiny.
Ceramic caps like those shown rarely fail and if they do there are signs, What is the component notation for them on the board, If they are C something then caps, the prefix should tell you.
 

Tonyr1084

Joined Sep 24, 2015
7,956
Thank you for the help.

The back of the board looks great, and I can't find any burn marks or corrosion.

The electrolytics test out fine, so I am not concerned about them yet.

Why would the ceramics test out so differently if they haven't failed?
I was given a TV because the horizontal control didn't work. Though looking at the solder joints on the horizontal control section of the PCB didn't reveal any issues I went ahead and fluxed and reflowed all the solder joints associated with that part of the board. The horizontal control issue was fixed. Sometimes you can't see a solder fracture but that doesn't mean it's not there. Many PCB's are built with two sides and the holes that go through the board are plated through. Sometimes that inner hole can fracture and lose connection. Reflowing the solder will often solve the problem even though the fractured copper may still exist. The solder can bridge across the fracture and everything can work as expected.
I suggest replacing the timing adjust potentiometers, because they are the device that is most likely to be intermittent.
I was going to make this same suggestion. I've had old stereo's with bad volume or balance controls due to excessive wear and dirt. Before you take the steps to replace the pot you can try spraying some contact cleaner inside the pot - provided you can access the inner workings of the pot through some opening in the potentiometer. Some are sealed and you can't clean them.
I just took the momentary switch off, and the contact on the rear of the button is steel, which is an odd choice. It's mostly rust now. I would guess closing it in its current state does nothing at all.
This is my suggestion; get some very fine sand paper and polish the contacts and see if that solves the problem. If the problem goes away then make it your #1 mission in life to replace that switch because once they've gone that bad there's no hope of bringing them back to being 100% reliable. If you do polish it it may work for a month or two then fail again. That's why you identify the problem or problems first. Then you fix what needs fixing.
 

Thread Starter

Art Duino

Joined Nov 30, 2017
52
Sanding the switch didn't get me anywhere. I don't think any current gets through. I don't really need the switch. I have never wanted to use it. I ordered a waterproof momentary switch anyway. The connectors that hook the switch up to the rest of the circuitry are pretty nasty. I didn't test them. They may not be conducting at all. I will fix them when I put the new switch in.

Since the switch is open by default and also open by virtue of corrosion, I don't think it's causing problems now.

The "caps" appear to be varistors, so I am not messing with them right now. I found varistors on the web which are identical except for the values.

I think replacing the pot with a resistor is a good idea, since there is really no purpose in changing the gate timing.

The gate is working right now.
 
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