Problem

[jess_her]

Just for laughs I went and looked at my Iron it's hotter then 500F.   Do me a favor find a junker board and crank the iron. Don't camp you might be supprised. A radio tec taught me this.

[chrisatpsu]

try to get another pic of the bottom (where you solder) of the board. without a glare from the board.  maybe at a 45 degree angle so we can see the soldering a little better.

[mnarel]

Ok.  I pulled and replaced the 16 chips above the heat sink with no resuts.  I'm resoldering the triacs at a higher temp to ensure a clean bond this afternoon.  Once that's done (and assuming I haven't corrected the problem) I'll try and get a few pics of the back of the board without so much glare on them.

Thanks for all the suggestions so far.

[RJ]

The issue will have nothing to do with the triacs or optos. You are looking for an issue in either power, the pic or the display chip and it little 2700pf capacitor.

Post good pictures of the of the bottom and we will see if we can see anything.

RJ

[mnarel]

I've replaced both the PIC and the display chip with ones from a fully functioning board yielding no results.  (I also placed the chips taken from the problem board in that other unit and it works fine).   From this I'm concluding that the chips themselves are out as the source of the problem - correct me if I've missed something there.

I'm attaching pics of the relevant portions of the back of the problem board for comment.  These are shots of the display area and of the PIC area.  I have to believe something is wrong here, that or the sockets themselves are bad (or were damaged during my install), though I can't see any obvious issues.

[CaptKirk]

I keep seeing something that looks like a short on the LED? connection just to the left of the camera flash flare in the first picture.  It seems to be there in other pics also.

Maybe a short on the LED? connection above the camera flash flare on pic two also.

[mnarel]

Here's a few additional random shots of the board from both front and rear.  I've removed the display modules, display chip and PIC to show the socket condition.  Can anyone spot anything amiss?

This one really has me stumped.

[mnarel]

And a final two more.

...checking for the short noted above.... not seeing anything.  Does it still appear in the new photos?

[CaptKirk]

The 485 chip near the large cap is in backwards- maybe - sure looks like it!! It is a 485 chip (photo is too blurry there but I think I see the ST logo so it should be).

Can't tell if the short is there or not from the last pics.

[trekster]

Good call Kirk.  It looks that way to me also.

Ron

[gforman]

That may not be the problem, in the first photos it is installed correctly.

[trekster]

Good call Gforman.  It looks that way to me also.   

Ron

[Garyi]

Have you looked inside each of the sockets to be sure there are no solder bridges? I have seen where solder will run down the leg and inside the socket.

[rm357]

I'm a little concerned about the solder joints on the two marked resistors (the 15K ones near the transformer). It does not look like the solder flowed through the board. I am also a little concerned about the solder joints on the back of the big capacitor.

I prefer to work with a really hot iron and move fast - as soon as the solder metls and flows, it's time to move on. Usually ~3 seconds or less per joint for the small stuff: resistors, capacitors, sockets, and such. If you have to keep the iron in place for more than 10 seconds for the solder to melt, it's either not hot enough, not stong enough (wattage), or you are working a heavy joint - like the spade lugs on the MR-16 or the fuse socket...

One other thought, if you have a multimeter, you may want to check the 3.3 and 5 volt regulators to make sure you didn't swap them. They look a lot alike and you really cannot tell once the heat sink is attached.

Good luck!!
RM

[RJ]

Push the reset button in and hold it. Then power up the board. If it works with the buttonheld in you have the reset button backwards.

RJ