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Old 24th February 2013, 07:23 PM   #21
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Quote:
Originally Posted by nigelwright7557 View Post
Why not just an RC as I suggested earlier ?
No need for switches.

I would also put a diode across the resisitor to discharge the capacitor on power down.
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Old 24th February 2013, 09:39 PM   #22
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Hi,
Just to show how easy it is done using a micro attached it is an schematic showing the way I will implement it using the Nano8.
Also here it is the program use to control the mute and the shutdown.
Nothing to it. Also this can be use to control any amplifier start up.

'This program will control the mute and the shutdown
'At the turn ON of the amplifier

Main
High P0 'Enable shutdwon by applying 0 volts to the shutdown pin 2.
low P1 'Enable mute by applying 2 volt to the mute pin 3.
Pause 10000 'wait for 10 seconds to allow the PS to settle
Low P0 'disable the shutdown by ampplying the rail voltage to the shtdown pin 2
high P1 'disable the mute by applying zero volt to the mute pin 3
stop
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File Type: jpg Shutdown and mute control.jpg (92.1 KB, 63 views)
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Old 24th February 2013, 09:46 PM   #23
xrk971 is online now xrk971  United States
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Quote:
Originally Posted by nigelwright7557 View Post
Click the image to open in full size.
You don't have pin 2 (SD) shutdown connected to anything here. SD needs to be held high (greater than 2 volts) a couple of seconds after power is applied to Vcc. I agree no switches if you use a diode or resistor to drain capacitor. Your 10 uf and 10kOhm time constant is only about 70 msec, is that long enough for SD circuit to latch while power stabilizes?

Here is a sketch (sorry it looks so bad, all i can do on android tablet).
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File Type: jpg tpa3122sd.jpg (65.8 KB, 58 views)

Last edited by xrk971; 24th February 2013 at 10:07 PM.
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Old 24th February 2013, 09:57 PM   #24
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Quote:
Originally Posted by Mark2727 View Post
Nigel,

I'm not understanding what you did. Could you give me a sketch and do you mean by "PIC", a printed integrated circuit?

<snip>

Mark
A PIC is a microcontroller with built in A-D and D-A conversion. He's using it to give it some 'smarts' - watching when power is good and so forth. There are a tremendous number of possibilities when adding a computer to the project. If it sounds like overkill it actually isn't and you'll find a bunch of things you may have thought about but didn't bother with because discrete logic can turn into problems as well and what's worse, logic gets corrected with 'cuts and jumpers' whereas logic errors in your controller just get erased and re-programmed. The same controller can also be used for remote control and other interfacing.

G
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Old 24th February 2013, 10:10 PM   #25
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Hi,
Stratus46 you are absolutely right. People still do not understand how easy it is to control any equipment using the micro processor and how easy it is to program it. I like the Nano for the prices and also how easy it to programming it in basic.
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Old 24th February 2013, 10:16 PM   #26
xrk971 is online now xrk971  United States
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I say an RC circuit to SD pin number 2 is more foolproof because you don't have to worry about PIC being alive first to work and don't need transistors etc. I agree that microcontrollers are awesome and very powerful for the price of a good electrolytic cap.
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Old 24th February 2013, 11:43 PM   #27
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Quote:
Originally Posted by tauro0221 View Post
Hi,
In the schematic the shutdown pin 2 it is connected to the + voltage means that the shutdown it is disable. Zero volts means enable. The mute pin 3 it is connected to ground. Zero means that the mute is is disable. 2 volts means that the mute it is enable. How much voltage your are using in you PS? I may come up with a schematic using the basic micro. I can make the circuit using the micro basic nano 8 if you are interesting. I will programming it for you. It is a simple program.
Hi,

Thanks for your offer regarding the basic micro. I wouldn't have the foggiest notion how all that is done. I will take you up on it unless an easier solution can be found, like the resistors and diode suggestion.

I'll be using 24VDC when that power supply arrives. But right now the one I'm using runs about 18.4 (with no load).

I can measure the voltage on those pins if needed. Set meter to DCV, correct?

So, please stay tuned!

Mark
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Old 24th February 2013, 11:52 PM   #28
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Originally Posted by xrk971 View Post
This problem must have an easier solution than the complicated schemes with external parts and programming. .................................................. .................................................. ..................

EDIT: You can skip the 3-pole switch by putting a couple of 1 Meg ohm resistors in series to the positive electrolytic cap terminal to drain it to ground slower than the 100 k ohm charges it (20 x in this case). Then it is all passive.

xrk:
I sure hope you are right and this could be solved with a couple resistors. As I understand you, it would be (2) say 1/4 watt 1 megaohm resistors attached from lug 2 of the chip to the positive lug of C12?

Thanks,
Mark
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Old 24th February 2013, 11:56 PM   #29
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Hi,
Your are welcome any time if you decide to use my circuit design. You can built it in small circuit board. Parts are available in any Radio Shack store and you can buy the micro from Basic micro. We can exchange micro once I programmed it. I have some spares Nano 28, Nano 18 and Nano 8.
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Old 25th February 2013, 12:45 AM   #30
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Originally Posted by tauro0221 View Post
Hi,
Your are welcome any time if you decide to use my circuit design. You can built it in small circuit board. Parts are available in any Radio Shack store and you can buy the micro from Basic micro. We can exchange micro once I programmed it. I have some spares Nano 28, Nano 18 and Nano 8.
Tauro
Thanks, well, I'm not entirely certain I understand your circuit there in post #22 right now, but we can clarifiy that later if need be.

I'd be inclined first to try the simple solution with resistors (if I am understanding XRK correctly).

If that doesn't work, I guess the Nano 8 it is. I'd appreciate your help if it comes to that, yes.

Oh, I don't about getting parts for your circuit at Radio Shack. Seems like everything I need I have to mail order. Radio Shack seems pretty useless anymore.

You need $4 worth of parts and it costs $12 to ship them. That, and being over my head is what I dislike about this hobby. What I like about it is fellows like you jumping in to help when that happens!

I'll let you guys decide what the best solution is. It's beyond me. I'm just a rookie kit building who barely undestands what's going on. I know a lot more than I did four or five years ago so I'm trying. But programming microchips and putting together breadboard circuits is biting off a lot for me. I'd give it a go of course, but with someone looking over my shoulder so to speak.

Regards,
Mark
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