LE only has first 8 channels powered & channel 4 is always hot

[kbowen]

I plugged in my LE just to run a test on my lights & channel 4 stays hot @ 120 volts even when board LEDs are powered off. Channels 9 through 16 have no voltage. All LEDs on the board go green. I have looked at the solder joints & there are no shorts that I can see. Is there a common factor for the channel 9 through 16 that may be causing my issue? Any troubleshooting help would greatly be appreciated.

Thanks! 

[rrowan]

Channel 4 could have a bad triac or optic chip (8 pin chip in front of the heat sink)
Did you plug in both power cords?  The right side powers up 9 to 16 side.

Rick R.

[kbowen]

Wow I feel like a goof! I was doing some reading & thought that you only needed two power cords to run higher amperage ! As for the optic chip, guess I will try to swap them around & see what happens. Thank you so much for the quick reply. Lights on the roof & getting nervous.

[kbowen]

Channel 4 could have a bad triac or optic chip (8 pin chip in front of the heat sink)
Did you plug in both power cords?  The right side powers up 9 to 16 side.

Rick R.

Now I have swapped optic chips with no difference. So I guess now I am looking at disassembly or desoldering the triac for channel 4. Is there any way to test that to make sure that is what it is , or is that pretty much all that is left? Oh & does one power in power up the board & the other just supply power to the last 8 channels?

Thank you !

[pk]

If you remove the opto for channel 4 and it is still on then the triac is bad or there is a solder bridge but you said the solder looks ok.  Did you look at the solder on the top side?

The left side power connection provides power for channels 1-8 and also the on-board power supply htat runs the PIC and LEDS.  The right side power connection only supplies AC to the triacs for channels 9-16.  A lot of members connect the right side to the left side if the express is not loaded heavily (i.e. LED strings )  I use about a 9.5 inch wire to connect the left and right sides.  Connect both the hot and neutral and note that the neutral of the power connectors is toward the center of the board.

[rm357]

If you are running low power, there are some holes in the middle that you can use to jumper the left and right sides. I just cut some short pieces of either 12 or 14 guage wire and soldered them in place - there should be instructions in the manual. This limits you to ~15 amps for 16 channels, but if you only run a string or two per channel or are using LEDs, you should be fine. I bought one of those kill-o-watt watt meters and checked my strings before I started putting things up just to make sure I would be OK.

RM

[lineman]

If you find you have a bad triac remove the heat sink ( I know all those nuts and bolts but trust me it is easier with it out of the way) cut off the triacs legs and desolder each leg I have found the $11.00 desoldering tool from radio shack is a God send it the one with the desoldering tool with the red bulb on top its easy and quick. I had to desolder a triac aand this worked GREAT even for a newbie like me

[jnealand]

If you find you have a bad triac remove the heat sink ( I know all those nuts and bolts but trust me it is easier with it out of the way) cut off the triacs legs and desolder each leg I have found the $11.00 desoldering tool from radio shack is a God send it the one with the desoldering tool with the red bulb on top its easy and quick. I had to desolder a triac aand this worked GREAT even for a newbie like me

I second this procedure and tool.  Had to change 3 triacs in the last year.