2hb

powering more than 5v with DOUT module

19 posts in this topic

Hello, 

I was wondering if there was a way I could use a dout module to interface with incandescent bulbs that require more than 5v, I am not sure their exact voltage, somewhere around 12v. Would this be possible with an external power source somehow?

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it should be possible with a relais, a transistor or an IC specialized on switching.
Many greets,
Peter

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UDN2981 can even fit into the DOUT boards. They require a secondary voltage though (595 won"t run on 12V).

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Thank you, I appreciate the help, so a 2981 after the 595, are you saying it would fit where the resistor arrays would normally go? How would I supply the secondary voltage?

 

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I think it should fit in place of the resistor array, but please check the pinout. There's no header nor PCB trace for power; you have to solder something to the DIP socket. I recommend limiting the current after the 2981 with suitable resistors. It might be better to use the DOUT as-is and put together something on strip/veroboard with a 2981. What sort of current?

Also check here:

It depends on your particular revision of DOUT. I believe the latest ones require no trace cutting. 

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I'm not sure if i did this right, but I connected the positive from the 12v power supply to the bulb via a multimeter, and the ground of the bulb connected to the negative of the power supply, it read about 14A, would that be the correct way to do it?

I haven't ordered the dout module yet, so it would be the r5 version

so would the vs and ground of the 2981 connect to the power supply's positive and ground through the two extra holes on the pcb where the arrays normally go? and then resistors would connect to the outputs 1-8 on the 2981?

 

 

 

Edited by 2hb

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In principle that sounds about right, but the current seems very high. Of course you have no resistor there, so the bulb will take what it can from the PSU. I think the 2981 can source only -500mA. If your requirements are bright lamps, then you should use relays or MOSFET transistors instead.

What sort of 12V lamps are we talking? If they're the small panel indicators, the 2981 will be fine. The other way around also works: ULN2803 provides eight sink drivers. You then power the bulbs at 12V and connect to the DOUT via suitable resistors. One drawback of the current boards is that there is no space for resistors onboard, so any current has to flow through the pinheader and typically thin ribbon cable wires. 

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Hello

5 hours ago, 2hb said:

it read about 14A

 14A ??? are you sure of that ? it's about 170W :fear:

Please give use the ref of your light bulb to ensure no measurement mistake at your side.

As Latigid say, no IC will help you here, you better use a power relay

Best

Zam

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You can use 5V DC Coil Relay, and you will find the right contact current rating for your bulb.
You can drive this relay directly, I already did it, connected to 595, it works.
Only a relay can handle this high current.

BUT! Like Zam said... 14A is huge, you use the right way to measure it but, are you sure? Your 12V power supply should be very big too, what is it?

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58 minutes ago, Antichambre said:

BUT! Like Zam said... 14A is huge, you use the right way to measure it but, are you sure? Your 12V power supply should be very big too, what is it?

To me 140mA make more sense for BAx bulb or 14mA which is low but in the range for T5.5 bulb...

Also 14A is not in the common range for most DMM...

@2hb can you confirm your A meter setting? mA or A ?

Best

Zam

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Okay, it was actually set for milliamps, so 14 mA not A, sorry for the misinformation! I am very new to this as you can probably tell

The power supply i've been using is just a 12v adapter 1500mA output. 

I would just use leds, but there doesn't seem to be an easy way to remove them from where they are installed without breaking them, they are for the afl pfl switches from an ssl fader module ! .. There's not really much information about what the actual ratings are for them, but I did manage to find them in this block diagram from the manual (top right):

5a30b473e5d35_ScreenShot2017-12-12at8.18

Hopefully this provides a little more information on them. 

Thanks so much for the help!

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Looks like the lamps are already driven by some sort of line driver/level shifter. This is good, as one can lift the LEDs out and wire to DOUT that way. Considering the way they are connected, it seems like the 2981 chip will work better.

If "IC4" still works, another option would be to connect to its inputs. The driver chip looks quite strange; what is the part number on the IC?

Is the idea to use both the normal function of the mixer and something MIDIfied? Or is it a carcass just to build a controller?

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Eh, I should read better...

Looks like there are already MOSFET drivers on the lamps. As they look biased to 25V, it seems that the 5V signal from a DOUT will not be high enough (did not check the transistor specs). But it could be tried with 5V supplied to the gate of TR7/TR8.

If you know what IC4 is, then the simplest way will be to match that voltage as driven from a DOUT. Please post the whole service manual if possible.

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I should be more clear on that, my idea was the latter, each fader module has a number of switches and leds, and in this case two incandescents, which were originally used for vca automation.

I wasn't planning on powering the modules, I was thinking just to basically bypass the whole circuit and access the switches and lights directly to use solely as a controller. 

ep320pc-2 is the part number for that ic http://www.datasheets360.com/pdf/-3584855117084061587

The modules aren't really in the best shape, and I'm not sure if they are in complete working order (neither did the person I bought them from) 

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hello

3 hours ago, 2hb said:

I would just use leds, but there doesn't seem to be an easy way to remove them from where they are installed without breaking them, they are for the afl pfl switches from an ssl fader module ! .. There's not really much information about what the actual ratings are for them, but I did manage to find them in this block diagram from the manual (top right)

This is not LED this is filament lamp, they are in the button, depending of manufacturer you should be able to remove the top transparent caps and have access to the lamp, is that EAO switches ?

If they are T5.5 filament you can replace them with LED (available in T5.5 package)

I guess they are 24V rated, +LAMPS in the schemo should be a separate 0V/GND for all lamps, as the -25 dedicated rail for "power" light

1 hour ago, 2hb said:

I was thinking just to basically bypass the whole circuit and access the switches and lights directly to use solely as a controller.

It should work. and if led/button are in a daughter PCB at frontpanel It should not be that difficult.

Best

Zam

 

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Hello! Yes exactly, eao switches, connected to a small pcb on the bottom, that is where i've been powering them, with the incandescents under the button cap 

That's what I meant to say, replace the incandescents with leds, i didn't know that was possible ! I feel silly now, I am very new to this sort of thing, I wasn't sure it would be so easy to interchange them

They are just situated in a way inside the switch that seemed impossible to get out without a special tool, they are only 3mm, so t1 size? It is really hard to find t1 remover tools

I tried using a precision flathead screwdriver to remove them and sure enough I broke some in the process, but I ended up just using a piece of electrical tape to remove all of them ! 

I just tested with a 3mm led in place, so now I just have to connect to a dout module. So I'll be using leds now with the dout as is. it's better that I keep things as simple as possible ..

Thank you Zam! You help me once again

And even though i'm not using the incandescents I still appreciate everyones help!! I very much appreciate this forum and midibox in general This is my first project so you'll probably be hearing more from me

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Hello

6 hours ago, 2hb said:

I just tested with a 3mm led in place, so now I just have to connect to a dout module. So I'll be using leds now with the dout as is. it's better that I keep things as simple as possible ..

Good ! that will for sure simplify a lot the conversion to Midibox IO

side note, I'm interested to see the PCB assembly to front panel !

Best

Zam

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I'd be glad to share, there are two pcbs on either side, connected with a ribbon cable on top

All of the modules I have are the same model sl506, but are all configured differently it seems, they all have these different mods on the outsides of the pcb

On this one, the same "ic4" I posted earlier has a sticker with the word "Film" on it. They are from a 5000 series which i know were meant more for broadcast and post production. so maybe this was more formatted for film? 

Another interesting thing is the two extra buttons at the bottom. The sl506 doesn't have two bottom buttons on the front panel, but other 5k series faders do, so manufacturing-wise they didn't omit the switches based on the fader model, just the fader caps. There are even the leds inside, I know because I applied power to them and they lit up ! I'm guessing that later, they would make modifications by hand based on how the customer wanted their console configured, but it is all a mystery to me really

Also sorry about the quality, I can try to take some better pictures, I just have the camera on my phone

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Edited by 2hb

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