Ground and 5 volt connected on main board

I hope somebody has an idea what might be going on here. I meticulously built my Nava trying to take away any human error in case my unit didn't function properly, but something is truly funky. All the power measurements on my IO board are right on, and when I went through the build all the +15 and -15v were 14.96v and 14.88 so I thought I would be good to go. It,'s when I got to the Sequencer section things got weird. It appears that all my 5v and grounds are connected. I don't have the IO board wires connected and I was doing continuity tests with my DMM. For example if I take one probe and place it on the 5v pin (#8) of jumper 2 and place the second probe anywhere else you should get 5v it's perfect, but I also am getting a connection beep from my MM if I touch it to any and all grounds. It shows that the 5v is even connected to the main power connectors 2 ground wires and the ground of connector 3 pin 4. I don't see how all the grounds are connected to 5v, could it be a flawed circuit board? I hope not since I've already neatly soldered over $300 worth of components to it. I can't find one spot where the 5v and ground do not seem to be directly connected, except for the IO board which is an entirely different board. I feel like I'm going crazy. I was so proud of this job, this was the best looking board I've ever put together and I've soldered a lot of boards the past 7 years. I will be so greatful to any and all help I can get on this question since I have a beautiful, NON functioning Nava. The metal case from Happymum is gorgeous. I want to hear some sound... Thanks for reading my long question, but I thought I should be as thorough as possible.

Danny

I can't believe I'm the only person that has this issue. Has anybody ever seen an instance where all the positive and grounds were connected to one another. How is this even possible? If i take one probe of my MM and place place it on any of the 595's pin 16 or 8 and touch either ground or 5 volt or any other IC's I have a connection and that goes for all the IC's including the Atmega 1264. Even if I disregard the 8 pin connector thinking that's where the problems lies, it still happens. I take my MM probe and set it in either the ground spot of the ICSP or the 5 v and I get the same results. I don't understand how the entire top portion of the build is flawless with perfect readings on every chip, yet when it comes to the Sequencer the positive and ground are linked together. Could two traces have been accidentally crossed up during manufacturing? Please, somebody shed some light on this, I feel like I'm in the twilight zone. I might have to speak directly to Vincent when he's back from vacation, unless somebody in this forum has much more knowledge than I do.

As my sequencer is not yet populated I have checked continuity of the traces. All 5V traces show continuity between them and I'm not showing any continuity towards digital ground.
So either you have a faulty board, which would really suck, or despite your meticulous soldering job you made a short. With certain components at less than mm's close to each other I also sometimes solder two points together by accident. Even after 37 years of soldering pcb's!

You probably did, but maybe check there are no rests of solder or rest of cut offs making shorts. I had a tiny spec spoil my day when I made my Yocto.

Thanks for getting back to me. After now spending several hours of looking at both sides of my board and still everything looking fine, actually very good, I think I might have narrowed it down to the LCD screen. There's a metal band going around the unit just under the screen, and then there's two small leads coming up from the bottom of the LCD but only one of them has been soldered at the factory, the other just comes up through the hole. If I place my MM on any 5v or ground and touch this metal band I have a connection, which might be normal, but having a connection to 8 of the 16 pins doesn't seem normal. I hate to desolder the 16 pins and remove the screen if that's not my problem, I would certainly not be a very happy man. I do thank you for your input and I will continue to work on this issue until the problem is found. I think I dreamt of the board last night.

Those 2 small leads are from the backlight led. They should be both soldered.
Looks like you're getting close.

As mine is still loose, I have measured it. The metal casing is not connected to ground. There is however a jumper point (J6) that allows you to connect it to ground.

Here's a datasheet for the pin outs
http://www.peterparts.com/%5CCatalogPag ... %5C612.pdf

Thank you very much for your help, I really do appreciate it.
Danny S

I just wanted to give an update. I couldn't find anything wrong after many, many hours of searching, so by the advice of Altitude I am going to remove the LCD and see if that is where my problem lies. I'm waiting on a rework station I ordered and I should have an update this Friday or Saturday, the 19th or 20th of August. There was NO way I was getting that screen off with just a soldering iron, solder sucker and wick. I don't know if anybody really cares since it doesn't look like anybody else has experienced this issue, I guess I'm the lucky winner. Hopefully I'll have something positive to type next time I'm here.

Take care
Danny S.

Did you found an error after removing an LCD?

I'm going to do it today, my desolder gun arrived late last night. I will post as soon as I find out, I sure hope this is it.

interesting, measured as you described and Im getting the same results.. even noticed overheat on ic113.