I killed it help needed

[lineman]

Hello felloow DLAers

 This is my problem, I did not have any output on channel 2 so I reflowed the terminal and triac  and I ended up with a bridge across the triac and did not see it. I powered the board up and channel 2 stays on I removed the bridge and now the readout that says lnyx , 60 hertz does not come on what did I blow prior to doing this everything work great except channel 2 I am not sure why the test function don't work now can someone point me in the right direction I am sure it has to do with the bridge but instead of guessing I will let the smart ones guide me

[trekster]

Fuse on left side?  It is what supplies power for the 5 and 3.3 volt stuff.

Ron

[lineman]

Fuse on left side?  It is what supplies power for the 5 and 3.3 volt stuff.

Ron

I still have the 3 volt 5 volt leds lit check the fuse anyway it is good

[rrowan]

If all of the solder joints are good then. Then try to reflash the pic or swap it out with another one.

Rick R.

[lineman]

If all of the solder joints are good then. Then try to reflash the pic or swap it out with another one.

Rick R.

Rick I reflashed the pic and all is good Le goes thru test function, I still have no output on channel 2 I am sure it is the triac but where  the read out for the starting channel 001 after a few seconds the middle digit goes out if I hit the select button it comes back on for a few seconds and goes out it always comes on when I hit the select button , I am going to remove the bad triac do you think this will take care of the problem with the readout

[rrowan]

If all of the solder joints are good then. Then try to reflash the pic or swap it out with another one.

Rick R.

Rick I reflashed the pic and all is good Le goes thru test function, I still have no output on channel 2 I am sure it is the triac but where  the read out for the starting channel 001 after a few seconds the middle digit goes out if I hit the select button it comes back on for a few seconds and goes out it always comes on when I hit the select button , I am going to remove the bad triac do you think this will take care of the problem with the readout

Nope the triac is isolate from the logic side with the optic chips (6-pin chip right below the led)
You might have a bad LED driver chip or flaky display

Rick R.

[RJ]

Also the little 2700pf cap could be damaged and cause this issue.

RJ

Sent from my Charge by Tapatalk

RJ

[rm357]

Does the led for channel 2light up?

I would swap the opto-isolator (6 pin chip) with another channel before i pulled the triac.

RM

[lineman]

Heres a update, I got home and verified the problem still was there , I then removed the triac and then powered the board up and all is well the middle display stays on like its suppose to.
 RM 437 I had already removed the triac prior to seeing your post and yes channel 2 led did light up RJ do you think I still need to remove the 2700 pf cap or would you just install a new triac and see what happens, Rick has already explained that the triac has nothin to do with the logistics side. I want to thank all of yall for the Help this is why this is the BEST Forum EVER yea I said it GOD BLESS

[rm357]

Here is how it works.

The PIC does all the heavy lifting, the triacs and display are just outputs - either can fail without directly affecting the other... The inputs all go to the pic - DMX and buttons.

If the display being flakey bothers you, then yes, you will need to swap out the cap. Eventually it will fail completely. Some have indicated that pushing the cap all the way down against the board can damage it and have recommended putting something like a toothpick under it while soldering it to the board, then removing the toothpick.

For the actual dimmer circuits, the pic output goes through the led to an led internal to the opto-isolator. The "opto" provides isolation between the low voltage control current and the high voltage output - internally it actually uses an led and an optical sensor so that there is no electrical connection between the low and high voltage sides. The output of the opto goes through the 180 ohm resistor and fires the triac. Since you already have the triac out, I would definitely replace it - that will most likely fix your channel 2 problem, but if not and the led works, that would only leave the opto and the resistor.

Good luck,
RM

[lineman]

OK heres a update, I replced the 2700 pf and the triac still no power to channel 2 so I removed the opto on a gamble and put a working opto from one of the other channel and now channel 2 works . I guess I  the opto when I had the bridge on the triac, am I thinking right or is this not possible still learning, BUT HAVING FUN Sure wish I had thought of ordering some opto when I ordered the triac and 2700pf oh well its just shipping cost twice live and learn THANKS EVERYONE FOR THE HELP Yall ROCK

[rm357]

Congrats on the repair. If you are placing another order, i would suggest getting a couple of extra triacs, optos, and '485 chips. These are your external interfaces and the most likely to get zapped.

RM

[lineman]

Congrats on the repair. If you are placing another order, i would suggest getting a couple of extra triacs, optos, and '485 chips. These are your external interfaces and the most likely to get zapped.

RM

Thanks for the advice, On my first order I did get extra's triacs and 2700 pf on this order got extra optos didn't think about or read your post in time to add 485 but I will the next time

[pk]

It is good to know you got it fixed.  It is always a good to have a few spare parts on hand.  Thank goodness for those sockets!!  It is not fun unsoldering IC's from a pcb.