ICs soldered directly to board, doesn't boot

[RevMen]

My friend really wanted to help with my light show this year, so I gave him a Lynx Express PCB plus all of the parts to put together for me, which would have saved me a lot of time.  He made several mistakes, including soldering all of the optocouplers, the ST485BNs, and the H11AA1 directly to the board.  I assume that any of those ICs could be damaged due to the heat of his soldering iron.  I'm trying to figure out which I should attempt to replace.

Both the 3.3V and 5V lights come on OK.  I am also able to connect to and program the PIC through the ICSP header.

When I power the board up, however, nothing happens, other than the 3.3V and 5V LEDs lighting up.  Would the loss of any of those ICs in particular lead to this problem?

[rm357]

Hmmm,

First - verify orientation of all chips
Second - if you have a voltmeter,verify that the 5v and 3.3v are correct and not reversed (the leds would still light...)

If those are correct and the PIC is programmed, the 3 7-segment displays should start scrolling a message. If that's not happening, I'd try is replacing the little capacitor. There is a lot of stuff on the forums about that capacitor anad how it is installed...

I'd also spend some time looking at all of the solder joints to makes sure they are good - no cold solder joints, no bridges... We on the forums always like to see pictures - No one will laugh, we've all made our own mistakes and some of the folks here are good at spotting things...

Good Luck!
RM

With the chips soldered directly to the board, it just makes troubleshooting and repair more painful. Depending on your friend's soldering skills, there may or may not be damage.

[mokeefe]

I wouldn't focus too much on that small 2700pF cap.  I believe when it's bad you end up missing the display on one of the three 7 segment LED modules, not all 3.  You may want to check the orientation of those modules as well.  As always, posting some good photos of both side of the board is often very helpful.  There are folks on here with keen eyes who can spot issues from the photos.

-Mike

[jess_her]

I would look closely at solder joints and IC/chip orientation. For me I also wouldn't worry about the IC's (chips) soldered in directly. The sockets are just for ease of chip replacement. SO I wouldn't touch them if they are working. You just have to use a volt meter for diagnoses instead of chip substitution.  I would try to get the board running the best I could before doing any chip replacement if any.
1)Work the problem from power (3V, 5V) 
2)check the three switches IF the reset button is in backwards it won't let the board boot. To test this hold the button down while powering it if the displays start scrolling then the reset switch is in backwards. Watch out for the 110V. Mode and select switches will cause some strange programing and testing but will let the board boot.
Switch orientation, looking at the back side of the board if you can see a plastic pin sticking down into the hole between the two solder pins then it is installed right.
2)logic (pic, displays, SAA1064 display driver and H11AA1 zero crossing)  3)Then go to the output section( 1 - 16 channel LED's, 3024 optos and the trics.
If you need help with testing, I or someone else can help walk you through this.