Jump to content
Light-O-Rama Forums
paulanator

CMB16D-QC Problem voltage drops

Recommended Posts

I have a problem my partner and I have been troubleshooting for a couple of days.

I have a CMB16D-QC that had been running for several years. It runs a 12v Solenoid (for pneumatics on my snowman) Suddenly last year it stopped working. We replaced the solenoid and same issue. What happens is that a signal is sent to the controller board and nothing happens. The solenoid works with the manual switch on it. The light on the solenoid lights up when a signal is applied and the solenoid makes a low humming sound. But the signal from the computer will not activate the solenoid.

We found there is a voltage drop to 7v when the load is applied with the signal (see below)

Here is one little point that hopefully I don't get beat up on, but I am using Xlights as my software and running this through a Falcon controller with DMX. Again, it was working and all of the other DC boards and LOR stuff is working great. I just wanted to mention this in case there could be some odd issue there. It ran fine on the LOR network and ran fine for a couple of years on the falcon/xlights network.

Lastly, one odd thing, both of the boards I am using have a Transistor broken off from cable stress. I never even realized it til now. It would not make sense that would affect the other channels, but I thought I would mention it.

Troubleshooting steps

We have tried:

Another exact same board, same exact problem

Measured voltages on the channels and with no load, the channels are getting 12v when the signal is sent

Measured the load while signal is being applied and the voltage drops to 7v. This is consistent with both boards and even a second Solenoid) This is the obvious problem.

Measured current across the channel and it was normal, and not pulling more than .15a when applying the signal

Summary

The one thing I have not tried, and that will be tomorrow, is to add 12v to the barrel connector.

It is odd that it worked for several years, then suddenly stopped working.

If anyone has any ideas or thoughts on this, I would appreciate some feedback.

Thanks,

Paul

Share this post


Link to post
Share on other sites

Does your solenoid have a catch diode. That would make it polarity sensitive (the diode is normally back biased)

The purpose is to grab the spike when you turn the power OFF. White Stripe to minus  (the port #)

If it did not have one, you may have fried something on the board

  • Thanks 1

Share this post


Link to post
Share on other sites

Do you mean fried the solenoid?

Not sure about the catch diode.

It does have an led near where the power comes in. The LED lights up ok.

Share this post


Link to post
Share on other sites
25 minutes ago, paulanator said:

Do you mean fried the solenoid?

Not sure about the catch diode.

It does have an led near where the power comes in. The LED lights up ok.

Well, if the LED lights, the polarity is probably correct. Not knowing the solenoid. some have 2 coils. both are in circuit to PULL, the one switches out to HOLD.

How the switching is done is is per device ???

Have you tried with no tension (load) on the actuator? The operating load may be too heavy/stiff

Share this post


Link to post
Share on other sites

Thank you for your ideas on this, We finally figured it out today, thanks to my friend who ran a TV shop for about 20 years.

We put a 100uf capacitor across the channel, and that worked.

Needless to say I was amazed, but he said something about the pulse width modulation and the capacitor storing up the power to give it a full 12v to the solenoid.

Strange fix, but it works. I am still confused of why it worked for a long time, then didn't. But we have a fix and all is well.

Thanks again for your taking time to help troubleshoot.

Paul

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...