Built a custom D8B external power supply

[RJH_MUSIC]

I also Read back through this thread to page 2 where Carlo described in March 2020 a problem with the Orange and black small wires that go from the LPS 152 power supply to the linear power supply board. These are the 5v sense connections. They are routed to pins 9 (orange/white wire) and 10, (black/white wire) on molex J20 and are connected to pins 5+ and 7- of J1 bfc. What Carlo explained was exactly what happened to me and means the Astek power supply is bad. Interestingly enough, I now think the damage I caused to the console is unrelated to the 5v power supply, but more related to shorting +16 to -16. I thought I read something about that too. I hope I did not fry the dsp board.

[RJH_MUSIC]

The Velleman kit used to generate +/- 16 may not Hebe enough amps. I idered one so we will soon see.

Yeah, this is a bit of a tricky part. I couldn't find any quick info on what power the +/-16V might pull. IIRC I bought a 35W supply from tracopower.... and went on to hook it up incorrectly( plus to minus, and vice versa), and fried some innocent chips..... I'm not at all certain whether 35 watts is enough.

Hi arjepen. I think I may have inadvertantly done the same thing. Can tell me fried, which chips?

[arjepsen]

Well, after I messed around a lot more, I came to the conclusion that I might have been wrong. There are some diodes on the power distribution board, that would short-circuit the supply, if it's connected the wrong way.
In the end I think I wrote it up to a problem with the 5V line. (I managed to boot with the +/-16V line all the way down at 13.something, so as long as you have a symetric supply there, I think you're good).
So in short: I have come to believe that for booting problems, the first thing I suspect, is the 5V line.

[RJH_MUSIC]

That is what I thought too, but I actually had two separate issues. I hooked up all the original supplies to the console and it still won't boot, but it does work on another console. SO I had a 5v Aztek problem but fixed that. Now, I still can't get the same power supply to fully boot the test console i was using. Everything works accept the audit, and I wonder if i shorted +/- 16 together and blew something up. Tonight i will try a third console and see what happens.

[RJH_MUSIC]

Well believe it or not I finally hit pay dirt. I connected another spare console that I had in a closet to all the original D8B power supplies and it booted and worked. I then removed the Aztec power supply and replaced it with the REL-150 30 AMP 5V power supply. On the 1st try with sense connected all of the lights came on and stayed on and the console would not boot. I disconnected the sense outputs and the console booted with meter flash, but still no audio. I then placed 2 jumpers on the linear power supply board on the unused terminals at the 5v molex connector, to supply +/-5 to pins 9 and 10 of the of the molex connector that is part of the bfc. Booted successfully with audio. One strange thing happens. When you first turn the power on, all the console let's come on solid for a second but they go out and then the console boots up. Next I will ohm out the cable again to check voltages at console.

Over the weekend I will put together a detailed parts list and instructions on what I did, with pictures. So phase 1 is complete. Phase 2 will entail attempting to replace the linear power supply and transformer with suitable replacements for +/- 16 v and 48v phantom power. I might forego the 48v.

[captainamerica]

WOW....you've got a lot of patience (and energy RJ) good luck with debugging things...wish I could offer more info/advice.

[RJH_MUSIC]

Too be honest, i was just about to give up the whole thing, but decided to try one more thing! Now i have to figure out what blew in my test console and how to fix it. I am hoping maybe it is just one of the capacitors on the control board and not the DSP borad.

[RJH_MUSIC]

Later today, as soon as I finish writing it, I will post a complete summary of my build with parts list and pictures. Stay tuned.

[RJH_MUSIC]

As promised, please follow the link below to see the instructions with pictures of my Phase - 1 build. The great news in this is you wind up with a smaller footprint for the remote CPU that is more quiet, cooler and replaces the ailing Aztec 5v power supply. Phase - 2 build will focus on replacing the Linear Power supply and transformer with suitable replacements.

https://drive.google.com/file/d/10wO0fX ... sp=sharing

[RJH_MUSIC]

Good day sports fans! Having some trouble and need some direction. Thanks to Ralph at Weritz.com for a ton of help on this issue, but still stumped. As you know, I recently completed a build of a new power supply remote CPU which was successful but not without a lot of setbacks. Once the build was complete, I used a test console to boot up and could not get audio. Then connected to a known working console and everything worked beautifully. So now trying to figure out what I fried in the test console. Since I had trouble with shorting the +/- 16v I assumed that something was wrong with either the Brain Board, DSP Board and or Power distribution board in the console.

To my surprise, when I replaced all of those components with known good boards and still no audio (no meter jump during boot up, no audio at any inputs other than 2 track inputs.) Even more surprising was that when putting the suspected bad boards into another working console, everything worked fine. So during the build process I must have damaged something else in the test console which is prohibiting it from booting fully with audio.

What I have observed on a known good console is that during the boot up process, the brain board and DSP board exhibit the following behavior.

Brain Board and DSP board green LED's blink continuously during initial boot. When console LCD displays loading plugins, red LED on Brain Board illuminates and blinks steadily fast. At the point that meters flash and the motors extend to zero, the green and red LED's on the DSP card come on full and are solid, no blinking, and the manual says that the red LED on the brain board continues to blink rapidly and the green LED should light solid. On my good board, the green light continues to flash.

ON the test console, the DSP board green LED never goes to solid and the red LED fails to illuminate. The d8b Service manual does not address the LED's on the DSP board, only the Brain Board. I am left with trying to figure out what other boards may have been affected by the short, and I am now looking at the Codec board and DCA board.

Does anyone have any ideas on what to troubleshoot next? Again, all the power supplies are working and everything connected to a known good console works.

Thanks

RJ