johnny5

ugh these are decoupling caps, one of them must be shorted though. i cant find anything else...

also what could have shorted all of them at the same time?

ok had some time to go over stuff today and..... :P c5 is shorted c4 shorted c3 shorted i guess this is why i have +5v to GND? im really curious if my dac is fried? i never left it on for over 5 seconds.

this is exactly what i did. i put the jumper in sideways just to 'mark it' after testing. i was measuring against the right side/analog. actually when you said that it is a GND pour i got really worried its not connected to anything except pin3 of ic3 and the connecting jumper pin. this is exactly what i was worried about so i checked continuty across all solder points and the right pour and only found the short at ic pin3. i may have went alittle fast at it maybe i need to go over again... j3 is a complete mess im ashamed of myself :P one of these days i need to go pickup a real desoldering tool. i will go into it with the wick some more and try to get everything out of it. if this is the spot where the laquer is damaged and the traces are interconnected i hope i can get around it. i would just like to say thanks for taking time in helping me with troubleshooting this.

with ic3 and the jumper removed i was getting continuity from ic3 to the bottomside copper flood surround section. if the short is under ic3 or the header maybe? i could probally get better photos and also keep in mind as of right now the board needs a once over (removed alot of solder for trouble shooting), solder and cleaning.

so i had some time today gave another once over.... what i noticed was that pin3 of ic3 is shorted to the flood somewhere? i removed all the solder from ic3 joint and the connected jumpers joint? i couldnt find any other shorts to the flood anywhere?

ok latest test dropped in two new tl074's and I read 0 on pins4 and 11 and my regulaor at the core got alittle warm. Nothing else is though. :P

LCD issue solved I think it was becuase I didnt have my pannel strapped down to GND.

ok so like i said all was good.... pins 4 and 11 of the 2 ic sockets where both reading +15 -15.(by the way im constructing a new +/-12v supply as we speak instead of changing resistors for 15v bipolar operation) i dropped in 2 tl074's powered it up rechecked power everything was fine for a minute then i was getting -30v at pin11 and .5v at pin4. thinking maybe the tl074's where bad i switched them out and tried some fresh ones, and the same thing. only this time i bumped pin10 there was a tiny visible short i powered down. pulled the tl074's and tossed the one. then rechecked voltages everything was fine. i was still reading 'ready' on my lcd then it began to flicker. new little problem one of my wires broke on my ribbon-cable to lcd(led+). no biggie quick re-solder, power on, core is 'ready', connect to ng to core i get no display. i mess with the contrast and i get top row blocks? i have searched all over the board for info but most info on the top row of blocks is pre bootstrap? now im scared i fried my DAC? maybe i still have a short somewhere on my aout? i might have another 20mins in the next hour to take a look at it i hope.

:o ok so it wasnt as bad as i thought. i was checking mta cables i had made up with a old analog meter i have. then 20 mins later there i am checking my ng with the same analog meter, and i noticed that i was continuity from + to - on my analog input. i honestly thought i had checked that already but i cant really remeber now. so anyway i went crazy reflowing joints checking continuity all over the thing and just when i was about to bash my head into the wall my old analog meter breaks. the cable pulls apart from the probe. i was about to chuck it against the wall and take some time away from the whole thing. then i calmed down and grabbed my reliable dmm. come to find out i was not getting full continuity across + to -... any way long story short all voltage test afterwards read fine. leson learned never trust a analog meter reading close to 0 for continuity. sad part is i will never really know exactly where the short was. :P thanks for the help fellas much appreciated!!!

ugh >:( I have a short from + to - somewhere can't beleive I didnt notice this already. Wish me luck finding it and I will report back with the progress.

ok so while checking continuity across vcc at j1 of the ng board to all GND and AGND connections, i did not find a straight continuous path any where. but i did notice that at most points my dmm would want to make a sound and it was reading 520? so i tried an ohm reading (not really knowing if this matters) i found that there is 41.6k resistance from the vcc at j1 to all AGND and GND on the board? this is racking my brain. ???

i havnt been able to stop thinking about it, and i am thinking that i need to pull the ng print the schematic highlight all components and connections dealing with +5v on the ng then look for continuity across them and analog gnd.

ok so I just got the chance to take a look at it. Now I'm powering up fine with 5v from j10(I must have made a bad cable the first time). But I am still reading +17/-12. So I first tried to disconnect the dinx1 just to make sure the short wasn't there. Then again +17/-12. So I disconnected the analog gnd from the ng board set my dmm to current at 200ua and measured in between gnd on my analog psu and gnd at j6 of the core, and I came up with -115ua. Ugh so I guess there is a short some where? Dose anyone have an easy way to narrow this down?

thanks for all the info! first i should mention that im slipping and had my ng interconected to the core via core j6 that is used for the mbsid. i originally had it hooked up through j10 and my lcd or the ng wouldnt light(i honestly thought that maybe i had old documents). then for some reason i seen the mbsid interconnect diagram and thought that it was ok for the mbcv(i cant remeber why i thought that was a good idea?). so all testing was done with j6 from the core. ok with that out of the way, i do have GND from the analog psu connected at j4 to the ng. Im currently away from home till tomorow. but im almost sure that there is a GND from j6 of the core. anyways im going to make a new interconnect cable for j10 of the core to j1 of the ng and hopefully it will light light up! so after i re do my interconnects correctly im going to recheck my voltage at pins4 and 11, hopefully that will do the trick. if not i will be disconnecting the analog GND and measuring MA across the 2 GNDs. i will report back with the progress!! and thanks for the link about bipolar mode i actually dont have any gear that use negative voltages yet but im sure it will be in the +5v/-5v range. what really stinks is my desoldering skills and to beat up these really nice boards its such a shame. wish i had read that before i assembled my board!

sorry i wasnt trying to recomend the use of j6. I was just mentioning the fact that i made a mistake interconnecting j10, and the image i was going by afterwards was indeed a mbsid. witch is completely wrong. :-[ as for the powersupply i am using a linear/analog psu. i have read here people using +15v/-15v for mbcv and thats what im using on my modular. so i shouldnt have problems there. anyway im sorry i feel like a thread jacker now! i have one going already acouple down from this one.

so im not as far as you but i did have j10 of the core hooked up to my ng and it didnt light up(now im thinking i miss wired somthing). so i also hooked up j6 via mbsid standards thinking maybe j10 was an obsolete connection? my ng light up! i was using a 9v dc wallwart. when i went and hooked up +15/-15v (from my linear psu)to the ng i get +17.7v at pin4 and -12.7v at pin11, but thats another story. im thinking maybe i needed to reference a ground from the ng board now. i was using a grnd from the core. not sure if that would make a difference. i am currently away from home for a bit i kinda wish i knew what pic i used? ???

So I burnt up the holes at j3 when trying to desolder the sil header, to replace it with a polar header type. So I tried j4 as a 15v input. It seems that these connectors are the same? Well I powered it up and at pin 4 I'm getting +17.77? And at pin 11 I'm getting -12.7? I recheckex my psu and it was at 15v? Now I'm completly baffled? How could this be possible? When the aout is run off a 12v supply you should get +12/-12. Any help would be great!