I wish that was my problem. I used IC sockets on all IC's and the IC's aren't even on my board. They're tucked away safely until I either repair this Nava board or sell it to some adventurous person.

housedet@comcast.net wrote:I wish that was my problem. I used IC sockets on all IC's and the IC's aren't even on my board. They're tucked away safely until I either repair this Nava board or sell it to some adventurous person.

Do you have the IO board disconnected when checking for continuity between 5v and gnd?

Ok, forget it. Just saw you first post... So you took out all(!) ICs of the sequencer? Are the 16 step switches soldered in already? Maybe you should search there too. Connect your probes and wiggle a bit on each of the switches. Maybe the contact comes from inside one of those tacts...

Yes, everything that can be soldered is neatly soldered, but I will give the switch idea a try. I've easily spent over 50 hours going over the board with a fine tooth comb and I would be surprised if this problem is from human error. Any joint that even looked slightly iffy, I reflowed it. I'm not one to give up, obviously, but this one truly has me very close. I was under the impression that the ground from the main section of the board was independent of the sequencer section, except when I place one end of the MM to the main ground then touch any place in the sequencer that's supposed to be 5 volt or ground, I get the dreaded BEEP. Thanks for looking at this question, I sort of gave up asking for any more help since it looked like I had a very unique problem and figured I would eventually have to find a repair shop that might take on the task, but I really like fixing my own problems when possible.

I'll let you know what happens after I mess with the switches.
Danny

housedet@comcast.net wrote:Yes, everything that can be soldered is neatly soldered, but I will give the switch idea a try. I've easily spent over 50 hours going over the board with a fine tooth comb and I would be surprised if this problem is from human error. Any joint that even looked slightly iffy, I reflowed it. I'm not one to give up, obviously, but this one truly has me very close. I was under the impression that the ground from the main section of the board was independent of the sequencer section, except when I place one end of the MM to the main ground then touch any place in the sequencer that's supposed to be 5 volt or ground, I get the dreaded BEEP. Thanks for looking at this question, I sort of gave up asking for any more help since it looked like I had a very unique problem and figured I would eventually have to find a repair shop that might take on the task, but I really like fixing my own problems when possible.

I'll let you know what happens after I mess with the switches.
Danny

Good luck! I really hope you'll finally solve this!

This is what I would do if I had this error and all other attempts fixing it failed: I would cut some 5v traces to localize the area where the contact between 5v and gnd is coming from. After you cut the trace go ahead and measure for continuity before and after the cut. This way you can exclude certain areas. For example I would cut at the following points:

black line = cut
blue line = bridge to fix cut



1. Step switches. The 5v via ends at step 1. Measure the 5v trace somewhere inbetween step 1 and the place where you did the cut. If there is continuity, then the problem definately comes from this area. If you don't have continuity, then the contact has to be outside of the isolated trace. Repair the cut with a cable bridge.




2. Remaining Start/ Stop switches and display. Cut on two places or remove R694 and do one cut. Measure inside the isolated 5v trace. If you have continuity between gnd and 5v, then the contact has to be inside the isolated part. Otherwise it's outside again. Only fix the cut at C607. Leave R694 out or do not fix the cutted trace at R694.




3. If you have continuity in the third part the area to be checked is quite big. Take the layout and do further cuttings to localize where the continuity is coming from...

4...

5...

6...


It's just an idea, but I think if you move on like this you should be able to narrow down the faulty place on your board...

I took your advice and checked all the switches with no luck, but I like the ideas about cutting traces and I believe that will be my next step, thank you for that. You can't imagine how frustrating it is to see all the grounds and 5 volts connected, it makes me feel like I'm going crazy. I built a second Nava hoping I might see where I could have possible have made a mistake, but the 2nd Nava is perfect. So I'm not sure if the ground has crossed into the 5v or vice a versa. I didn't think that the 4th pin of jumper (1), the ground, and the 2 grounds on the main jumper (5), should even be connected to the ground in the sequencer section. I wish I had x-ray vision. The good thing about this was, I was able to afford a second Nava and be able to use it, and I will have this messed up unit to come back to now and again instead of driving myself crazy when all I was doing everyday was going over the board and testing it, over and over. I appreciate you giving me a couple of other things to try, it means a lot to me.

Thanks again
Danny S.

Ive got my friend almost ready Nava with the same problems.
So there are more cases as yours....