Help with my Express please

[robelent]

I just started to run my preshow tests in the yard and I have one Express that is performing very weird.  When I run the test mode, it seems to work fine; however on a closer look I notice that the channel LEDS are a bit dimmer than normal.  The AC outputs start to turn on in order, but when it hits about channel 7 or 8 they stop turning on and all the other slow fade out.  Also when I push the select button the 3.3 volt LED dims a bit.
I have reflashed the pic, tried a new pic and still the same results.  Any ideas would be great.
 

[onesmoothhead]

Check for chip direction. It is very easy to put them in backwards.  It is also possible to crush the legs.  Verify the 3.5v, but it really sounds like a pins missing on a chip.  I had a similar issue and found a few chip issues.

Kevin

[robelent]

I have checked all the chip directions and pins all is good.

[rrowan]

I would check the soldering in the channel 7-8 area

Rick R.

[RJ]

Post some good clear close up pictures so we can look for issues that a second pair of eyes will pickup thats yours might be missing.

RJ

[robelent]

Sorry for the delay, I was out of town.  Any help would be great.

[jnealand]

Take the wireless jumper off.  Put the terminate jumper on if this is the last LE in the chain.  Probably has nothing to do with the problem you describe, but should be done.

[bisquit476]

Take a look at the items circled, especially the one with the arrow, looks like a burn mark on that one.

[robelent]

I have looked at those, the one with the arrow is the little 2700pf cap, if I understand it that is part of the Digital Read Out, and the 3 digit display works fine.  The other two are just the heat sink for the 3.3 volt reg, I had to take it out the first time I put it in.

[jess_her]

 I see that you don't have the center jumpers in. I assume that you have two  AC inputs into that express.  Is it possible that you have the neutral and L1/power reversed on one input??
For me  I use 14Ga zip  or lamp cord (LED lights) If you look on the side of the cord you can see two faint lines. That is the neutral  and of course the other is L1 or power side. I'm not sure how the express MO3032 or the Tric would react to the power bucking each other but it might cause your AC line to the controller to brown out.  I would expect this to happen when channel 9-16 turns on not 7 or 8. But I believe that on the bench going through self test it would test good and would test good with just the left hand power cord hooked up.
I dont want to try this on mine to find out what would happen   

[robelent]

Good thought, I am sure I had the neutrals connected right in the yard.  I did just test it both ways with the same results. 

[jess_her]

Ok  Lets check the 3.3V power. You need a DC volt meter. The ground/common side of the meter goes to the right hand side of the .1Uf cap at the top of  pic. The Pos. side goes to the 2K resistor below the transformer. Take your measurement while it is in self test mode. It would be best if you have  alligator clips that fits on the end of your meter leads so you can attach them to your board while testing.  If the voltage droops below say 3VDC then take a measurement again the common or ground from the .1UF cap to the upper right corner of the board count down three holes and it should be 5VDC. If you loose the 5VDC and the 3.3VDC the you have problems with maybe solder joints at  the transformer or Rectifier and it would be good to check the 4700 UF cap. IF you just loose the 3.3VDC  then the problem is at the LD1117c,cold solder joint or bad LD1117c.

Watch out for the 110 VAC It can put a hurt on you or worse.  The very best way to test this is to clip your meter on then power up.  If you have to, touch one lead at a time

[lonewolf41]

This sounds just like the issue i had with my V4 LE (I didn't see where it said what version yours was) that was suffering from the 3.3V regulator getting too cold.  Replaced it with the new one and my problems went away.

HIH,
-Keith

[jess_her]

he had a bad 3.3 regulator, he's running now