Another Dilemna

[p2h]

Hey guys, I'm stuck again at trying to repair this D8b I've got. Here's the latest scenario: 1). I've narrowed bad parts to the original mackie sync card (the meters on the board light up like it's passing audio everytime it's connected when NO audio is present at all) 2). I've replaced the LM317/337 pins 3). I have a CF installed running vers 3 that seems to run fine.

Ok, after the LM337/317 were replaced, apparently I still have a power shortage somewhere, I just can't figure out where: the board fires up, but I still don't have control of the physical faders OR the pan pots. I'm not getting 5volts from checking the inside of the CPU; when I power up the unit and it runs for about 1min or so, the onscreen faders TWITCH/JIGGLE up & down (sometimes/sometimes not)...so I'm debating on whether to jump ship or am I missing something that's simple to fix?? I need your help, because I wanted to have this done by the time the HUI probox is ready. Please help guys...

[munkustrap]

Hey guys, I'm stuck again at trying to repair this D8b I've got. Here's the latest scenario: 1). I've narrowed bad parts to the original mackie sync card (the meters on the board light up like it's passing audio everytime it's connected when NO audio is present at all) 2). I've replaced the LM317/337 pins 3). I have a CF installed running vers 3 that seems to run fine.

Ok, after the LM337/317 were replaced, apparently I still have a power shortage somewhere, I just can't figure out where: the board fires up, but I still don't have control of the physical faders OR the pan pots. I'm not getting 5volts from checking the inside of the CPU; when I power up the unit and it runs for about 1min or so, the onscreen faders TWITCH/JIGGLE up & down (sometimes/sometimes not)...so I'm debating on whether to jump ship or am I missing something that's simple to fix?? I need your help, because I wanted to have this done by the time the HUI probox is ready. Please help guys...

Hi, do some LEDs lite up on your d8b? then 5V is ok. The AD-converter of the d8b that converts the fader and vpot signals is supplied via the 12V supply. When that is broken, or the 12V ground (MGND) is not connected to the digital ground (DGND) then your vopts and faders will not work. Buttons/Displays will be fine.

Ave a look to my Manual How to make the d8b CPU/PSU silent, to check, where to put the GND Bridge between DGNG and MGND.
additional you can measure the voltages on the brainboard if everything is there (+/-16V, 5V, 12V)

[p2h]

Thanks Munk, I will try and let you know.

[p2h]

Hey Munk, quick question: could my problem be a bad power distribution circuit board?

[munkustrap]

Hi
yes, there is also the possibillity that one of the electrolytic caps on the power distr. board is blown.
But you can see that:

http://topfield.abock.de/wiki/images/d/de/Elkos.jpg
in this picture: the two upper Elkos are ok(left one marked red), the lower three are defect (two marked, the one in between not marked)