channel on all the time

[grumpy2076]

ive got a channel on all the time how do i fix this , or do i need to build a new controler? Theres power going throgh the 2 channel on my express but the led is not lit, when i play a sequence it stays on all the time but the led on the board works like its supose to.

[rrowan]

It could be the Triac is bad or the optic chip (assuming there is not soldering problem). Just because its easier (power off the LE) swap the optic chip with a known good one and then power up the LE and see if it works.

Rick R.

[grumpy2076]

Ok thanks i did check the chip and no change so must be the track.

[Jeffl]

Check for a solder bridge as well.  I built a new controller and had everything mounted, tested the board and noticed a stuck channel.  I ordered triacs, took most of it apart and then I noticed the solder bridge.

How could this make it by me.  I have built in excess of 50 boards in my days. What took me two hours to fix could have taken 20 minutes.

There is no need to build a new board.  Almost anything on these can be repaired with a little time and research.

[tbone321]

It sounds like you blew the triac.  It can be replaced but make sure not to overheat the board.  It's best to cut off the pins right where they meet the Triac body asnd then remove them on at a time.  The solder sucker from Radio Shack makes quick work of clearing the holes of solder prior to installing in the new Triac.  You really don't need to swap the opto to check it.  Just remove the one on the channel that is staying on and see what happens.  If the power remains on, then it is most likely the Triac an if it goes off, then it is either the opto or a bridge between the opto and the PIC. 

[fyb2000]

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I had the same problem, and found out that the triac was bad following the troubleshooting section for the LE.
Finding the problem is one thing, but changing the triac is quite a pain...I wish it had been the opto.

[tbone321]

The Radio Shack solder sucker actually does a petty good job of getting just abou all of the solder off of the pins.  It is fifficult to cut te legs off of the triacs with them between the terminal block and the heatsink.  I had the same issue with the 3V regulator and the solder sucker remove enough solder that all I needed to do was wiggle the regulator and itfell right out.  It may be a bit more difficult with the triac due to the heatsink but it's an inexpensive tool and worth a try.