Trouble shooting Please help steer me in right direction/ Self test results.

[GrumpkaXmas]

So, the good news of the day is board one of five is tested, working, heat sink mounted properly, unit is in the case, all wires properly run and attached, all channels of (except one channel needed a snubber which was a 50w spot).   All good very happy.  Done.

Board #2.   

Self check okay, BUT, when I checked the voltage meter I get some trouble.  Channel #5 dead.  no 110V, not nothing. 
 
I figure #5 is a IC issue, rather than Triac.  Remove MOC3023, and I find this?

How or why would this happen?  Is this a sign of something more serious?  Before I go further, please let me know what you guys think of this.  Almost looks like the person who built the board fried something with his soldering iron.  On the other hand, why the perfectly round hole in the pin slot?  VOltage surge?

I guess I'll test the triac next.  Maybe, nothing wrong with it.  Didn't want to go any further though until I understand why something like this happens.  No other signs of problems I can see...

Channel #12, voltage leak when meter checked up to 68v climbs slowely.  #13, 35v or so,  #14 3v.   When I plug in a 50w spot, it is in fact off, and the voltage will go down to zero.  All other channels stay flat with no load.   I don't know all that much about triacs, but this sounds like a something is up.  Under load, they work though...  Do I need to address this? 

EDIT: I popped in a MOC3021 (which I think is about the same as the MOC3023) just to check the socket on #5.  It works fine.  I'm just worried now, what made this happen to start with.  I guess I should change the IC socket just to be safe....

[n1ist]

If the middle lead on the triac isn't soldered correctly, all of the load current will try to flow through the MOC3023 and 180 ohm resistor instead of through the triac.  Normally it is the resistor that smokes first, but in this case the socket took the heat.  I'd recommend replacing the socket and MOC3023.  Also, with the chip out of the socket, measure the resistance of the 180 ohm resistor; if it is off by more than 10 ohms, replace it too. 

The middle lead on the triac is internally connected to the tab and thus thermally to the heatsink so it can take a bit of heat to solder properly.  Removing its screw while soldering (so the heatsink doesn't try drawing all the heat away from the joint) may help.

/mike

[pk]

that socket is ruined. The solder is shorting out the input of the optocoupler which would prevent the triac from turning on.

[RJ]

Both are correct, Change the socket and resolder all of the joints on the triac. This should resolve you issues. The two different MOC part numbers are not the same part you may want to get the correct one.

RJ

[GrumpkaXmas]

Awesome.  Thank you guys.  I would think improper solder job sounds about right.  I'll go back and reflow as much as I can. 

New parts on there way (including the MOC3023's).  I want to get each board 100%. 

Oh, and the leakage on the triacs?  Isn't that pretty normal?   I've tried to read up and search the threads.  Sometimes it hard to find old thread on the subject matter.  Don't mean to ask repetitive questions...  I'm not worried about it, as a snubber solves the problem anyway...

Thanks again.  That's as far as I can go until my mouser order arrives.

[GrumpkaXmas]

Good News, another board has been completed.  I replaced the burnt out 6pin socket, reflowed the triacs, and replaced the 3.3v LED.  cleaned the board, and placed the heat sink on properly.  Tested and ready to mount in the case.
Two down, three to go.  Thanks for all the help.  I must admit, problem solving and learning how to repair the board was fun.

Ok, now I'm on board #3.(of 5).  The first thing I found was sort of funny, sort of sad!  EVERY MOC3023 was installed backwards!  Which figures, as half or more of the 6pin IC sockets are installed wrong.  I'm not changing sockets, but I removed and re-installed the MOC's correctly.   I've installed two new ST485BN's.   Here's were I'm lost.  At first, only the 5v LED came on.  I was thinking the worse.  I shut down, checked all the 180 ohm and 330ohm resistors.  All checked well within tolerance.  Fired back up, nothing.  No LCD, just that lonely scary 5v led.   Shut down, and did something from back in my days of electronic synths.  I rapid fired off and on a few times.  BINGO We have ignition.  5V, 3.3V LCD screen.  A fully working board.  Plugged into Vixen, ran test, works.  Shut down, fire back up, DEAD.  Only the 5V came on.  I recall something about the pic socket being a possible issue.   Pulled the pic, and re-installed.  Fired back up, it works.  Shut-Down, back on, nothing but that 5v LED again.   

(update:  Pulled Pic again, cleaned it and the socket,  didn't work at first, flipped on and off, it works, turn off, come back, need to give it that little off/on flick to get it back on)

Not sure where to start.  I'm hoping this description might point to something specific. 

Alright, I'll get back to it and do what I can in the meanwhile.  Maybe, I'll stumble on an answer in the meanwhile.

 

[tbone321]

Unfortunantly, this is being caused by a bad regulator and this regulator may no longer be available.  I have a board with the same issue.  I'll have to do some more research to see if I can find something similar but I will probably need to modify the board.

[GrumpkaXmas]

Do you know which regulator?  I have a new L7805ABV, and  a LD1117V33C
Wishing I bought more maybe? LOL. 
Think I have two of each.   Even have a brandy new transformer just in case.

I'll have to do some homework too.  Not sure how to check them, beyond simple volt meter.  Beyond that, wouldn't know what to look for.  Especially, as the problem is intermittent. 

Thanks for the help. Let me know if you come up with anything further.   These boards were all such a mess.  Working on a V2 board.  Found a fried resistor with magic smoke marks, and another fried 6 pin socket...  What did this guy do to these boards?   

Well, at least by the time I'm done repairing 5 boards, I'll know this these things pretty well.  Building a new one will be an absolute pleasure.   

PS: Unrelated to above, different board, any clue as to where to start trouble shooting Zero Cross issue?  LED #2 not lit upon self test (version 4.0)
I've been searching for an hour on the forum.  Nothing comes up with any keywords.  I'm sure I must be missing an obvious guide or something.  Checked wiki, checked forum, check google, just nothing talking about the self test and the Z.C. LED. 

[n1ist]

What a fun way to start; at least you are very familiar with the Lynx Express now...

Zero cross is detected by the H11AA1 optocoupler between the fuse and transformer.  Make sure it is facing the right way and is the right part (H11A1 is a different opto and won't work here).  The two big 15K resistors next to it provide power to the opto.  Be careful since they and the opto are directly connected to the AC line.  The 2k resistor between the opto and the big resisitors is the pullup resistor on the low voltage side of the ZC optoisolator.  The right pin (nearer the big resistors) should measure 3.3V; the left side should pulse low at 60Hz so it will measure lower than 3.3V.  Those are the only parts involved (other than the PIC itself - make sure pin 16 is properly soldered) with the ZC circuit.

/mike

[GrumpkaXmas]

An other newbie triumph,  V2 board repaired, replaced blown out parts, tested and running : )

I think I know the answer, but can I reflash pic on V2 to latest firmware so I can have self testing?  I was going to just switch the pics from a newer board to try this, but didn't want to mess with a working board until I'm sure this would work.

I need to order a programmer so I can flash, but still not sure what to order.  Looking at PicKit 2, not clear if PicKit 3 is better....

[tbone321]

Yes, the most current version of the firmware will work on the Ver 2 as well.  As for the programmer, the PicKit 2 is easier to use but is unable to flash the newer 32 bit PIC's like the ETD uses.  The PicKit 3 can program all of the PIC's but has a steeper initial learning curve and the programmer software is not fully up to date.  If you go with the PicKit 3, use the ver 1 PIC programming software.  I have both and use the PicKit 2 for everything that it can program and use the PicKit 3 for what it can't. 

[jnealand]

Yes, the most current version of the firmware will work on the Ver 2 as well.  As for the programmer, the PicKit 2 is easier to use but is unable to flash the newer 32 bit PIC's like the ETD uses.  The PicKit 3 can program all of the PIC's but has a steeper initial learning curve and the programmer software is not fully up to date.  If you go with the PicKit 3, use the ver 1 PIC programming software.  I have both and use the PicKit 2 for everything that it can program and use the PicKit 3 for what it can't. 

+1

[GrumpkaXmas]

Thanks guys.  Looks like PicKit2 is where I will start.  If I find a need for PicKit3, I can always add a second tool to the growing collection of toys.     Glad to hear about the V2 firmware.  I love that little self test feature. 

[GrumpkaXmas]

Hello everyone.

I thought I should update the community as to where I am at with Lynx Express builds.

In a very short time, I've gone from knowing very little, to repairing five lynx boards and even building my first board from the ground up.  (worked on the first shot).  This has been a great journey.  I've learned so much. 

The reason I'm sharing this update is so other "newbie"/noobs will appreciate the lynx express boards.  With my limited soldering skills and electronics knowledge, this community helped me understand what to look for, how to make repairs, and confidence to take on new builds. 

Now, I'm very confident with my soldering and troubleshooting abilities.  I'm far from "experienced", but these boards are pretty easy to build and if needed, trouble shoot.  If you follow the Wiki assembly directions, you should be just fine.  I had an enjoyable time with my first complete build.  I'm looking forward to the next several LE builds.  I have eight to go and hope I'll be able to get even more this summer. 

Thanks for all the help guys.  It wasn't for nothing.  I'm a big fan of the Lynx Express design.  In fact, I'm hoping to get my hands on a bunch of Bobcat Servo boards next.  Loving this hobby.  Most fun I've had with a hobby in a long time.

Have a great evening.

Stephen

[RJ]

Glad to hear it, this is why DLA exist and why we keep commerical stuff out as much as we can, and make sure we only have one version of everything. This way everyone learns it and can help anyone else with the items.

RJ