Built a custom D8B external power supply

[csp]

Arjepsen,

Thanks for the info, I will have to have another good look at the system and will try to check the voltages on the output of the transformer.

I presume that if the secondary AC output is the same on both taps, then as they feed into the various DC sections, that it should work, but I would definitely tread VERY carefully, as I do not want to damage the desk.

David

[RJH_MUSIC]

You are so right about that. Too much stuff. Today I'm gonna disconnect everything it's connected to the 32 by 8 bus and then see if the hum exists if it does then I know it's within the mackie 32 by 8 bus and as you say it could be a faulty ground in the house.

[RJH_MUSIC]

On the 240v power supply, your best bet is to replace the ATX power supply with one rated for 240v. I might be wrong here but what we talking about is the input voltage not the output voltage. The output voltage is distributed to the Power distribution board Which sits directly behind the ATX power supply and has several fuses on it. From there power is distributed to the transformer and the + 5 power supply. The Linear power supply board receives 12 V from the ATX power supply, voltage output from the transformer and voltage output from the +5 and sense from the +5 power supply. The linear power supply board then regulates the input and produces +/- 16 and +48. Not sure which transformer whining you're talking about whether it is within the ATX power supply were on the big transformer. If you're talking about windings inside of the ATX power supply then as long as your output voltages are the same you wouldn't have a problem. If you're talking about the transformer winding changing that would blow up the linear power supply board.

[csp]

I will have to pull the CPU unit out of its rack and have a look inside to see exactly how it is all laid out to be sure which transformer that I am talking about, but from memory (about three years ago !!!) I thought that it was quite a large transformer and the it was located at the back of the unit and just off centre to the left, BUT I am not sure.

I will be busy for the next few days but should be able to have a look over the weekend and once I work out the exact transformer, I will let you know.

I am talking about the input mains supply being 240 volts as compared to the USA 110 volts and the output volts that I was referring to were the volts across the secondary windings of the transformer that has both voltages written on it ---- I would definitely disconnect where the secondary windings were going to, just in case the voltage across the secondary windings were almost double when connected to the 240Volts mains supply. I would also trace the wires from the wires from the IEC socket to check that they don't go somewhere else as well as the transformer that I am referring to.

If I can I will take a photo of the transformer in question and post that.

In the meantime I thank you fir your interest in the matter.

David

[RJH_MUSIC]

I understand now. There i only one transformer in the unit that is outside the ATX power supply. Mine is labeled 110. if you have one labeled 110/220, then what you say is correct. There are two windings. Using both yields 220 and using one (half) yields 110. I suspect that if the ATX power supply is set to 240, then you need to use the 220 winding on the transformer. But, i am not an electrician so take that with a grain of salt.

RJ

[RJH_MUSIC]

I received my new 5vdc power supply yesterday and installed last night. i just have to now rebuild the big friggen cable and i am ready to throw the switch on to test the setup.

Wiring up the power supply was a bit difficult and I am working on an assumption right now to see if it works. The TRC REL-150-1003 is the power supply. it has a single output 5 VDC configured as two screw posts for (-) and (+). The confusion is around the (sense) there is a pin block next to the outputs that includes 8 pins. Pins 1-4 are the sense configuration.

Pin 1 = +5
Pin 2 = +5 Sense
Pin 3 = - 5 Sense
Pin 4 = - 5

There are jumpers across pins 1-2 and 3-4. I called TRC and spoke to a technician who really could not offer any explanation as there are no written details about this in the box. I am guessing that with the jumpers in place, both the screw terminals include sense. Since that is not the way the d8b is configured, I assume that I have to remove both jumpers and connect Pins 2-3 (sense) to the linear power supply board from the d8b. (The d8b has 10 total wires in the molex connector on the linear power supply board that go to the console. Pins 1-4 are +5. Pins 5-8 are - 5. Pin 9 is +sense and Pin 10 is - sense. The LPS-152 power supply has 4 outputs going to the linear power supply board that are connected to that molex connector, +5, -5, +sense and - sense.

SO that is why I think I need to connected it as described. Otherwise, with jumpers, I would be supplying +/- sense to every one of the +5 connections in the BFC.

I got my fingers crossed. Tonight if finished, i will power up to see if it all works. I at least know that the OS boots and works at this point.

[RJH_MUSIC]

Having trouble getting 18 wires through 1/2 inch cable shield to make a 25' extension to the the umbilical cord between the cpu and console. As soon as I get that figured out I'll repost

[RJH_MUSIC]

No I finally finished the project last night and fired up the AB and to my utter surprise it wont-work correctly and I don't know why. I did make a 25' extension to the BF cable and I'm wondering if I have line drop which I will test today.

So the software fully boots up and the console operate all the lights work and all the buttons work on the console but the faders have no effect in this software the software 1 As well as the Pan pots. The interesting thing is that I can control the pancakes with the mouse within the software but not from the console to the software. Lastly With the mouse I can control the faders in the software but they have no effect on the consult and when moving to faders on the consult they have no effect in the software. I haven't even tried to plug anything into it to get audio yet. I ohmed out the pin outs in the cable 3 times and they are perfect. To me this sounds like a problem with the 12 V supply or the M ground but I can't figure it out Because everything with the exception of the 5 V power supply are all the components from the original d8b.

[RJH_MUSIC]

OK here is an update. I am really perplexed by this situation. I ohmed out every connection in the BFC three times. Next, I powered up and checked the voltages on all pins. Everything appears to be fine. The +/- 5v appears to be jumpy. But the 12 v is steady. Console bot up and goes through initialization stage, but t end there is no movement of the faders to zero and no meter jump. For the software I can adjust all parameters including panning but not the faders. So when you run a pwn pot inthesoftware,I the software, pan pot on the console moves. Touching anything other than buttons on the console has no effect. The next thing to try is to boot up another d8b and compare voltage on the pins in the bfc.

The +/-5 voltages fluctuate between 5.6 and 5.4. If I tweak down to 5.0, then the +/- 5 sense outputs drop to 4.0 and if I boost to 5vdc the the non sense output reaches 6.0 vdc.

Any ideas?

[RJH_MUSIC]

Sometimes I hate auto text. From the software using the mouse, I can move the panpots on the console and I can engage any button, but moving the faders will have no effect on the console. I can press any button on the console and the software will, display that, but the physical faders and panpots on the console have no effect on the screen.