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Need help debugging digital balanced attenuator (Amati by luvdunhill)

post #1 of 12
5/17/10 at 6:25pm
Thread Starter 

 

Beefy Said

Quote:
Ah, its easier if I just type it out......

Check your digital voltages first. Should be 5V from each 78L05. Should be 5V across one of the LED terminals, 0V across the other.

Check the encoder terminal block. Top three pins on the outside of the board are grounds. If you have the push-button switch, one of these goes to one half of the switch, another goes to the common (middle pin) on the encoder, one spare.

The pin with the arrow at the encoder terminals (PA0/pin13 on the ATTiny) goes to the other half of the switch. There is a good chance to troubleshoot here...... if you switch across PA0 and ground correctly, mute will switch on/off. You can measure voltage across the LED terminals to see if mute comes on and goes off with switch presses.

The other two encoder terminals (PA1/pin12 and PA2/pin11) connect to channel A and channel B on the encoder respectively.

 

 

Ok, so when i depress the mute switch the voltages across the LEDs stay the same.  The output level always settles down to 4-5mVAC. J2 is shorted.

 

I am reading 5V for the digital supply and +/-15V for the analog section.

 

Am I missing something?

 

Is it possible that the uC isn't programmed at all?

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post #2 of 12
5/18/10 at 6:36am

Have you tried spinning the encoder the opposite way (counter-clockwise)?  If you have the channels backwards, then it will work in the opposite direction.

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post #3 of 12
5/18/10 at 1:16pm

i have my parts and am about to start building, i have the black board, but this does not bode well, no help from the maker...??

any of the other guinea pigs get theirs to work?

how did you wire the encoder? is it working?

oh and what are the functions of the jumpers, is for gain?

can you supply shots of your board?


Edited by studeb - 5/19/10 at 2:59pm
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post #4 of 12
5/18/10 at 1:54pm
Quote:
Originally Posted by studeb View Post

no help from the maker.....

 

 


Why would you say that? Have you asked him for help? 

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post #5 of 12
5/18/10 at 1:58pm
Thread Starter 

Marc is helping me behind the scene. 

 

It should work straight away but isn't for some reason. Marc is helping me nail down the issue. 

 

Actually studeb, there is all the info you need for the attenuator in the OP itself.

 

J2 is for selecting the encoder (so you definitely need this)

J1 is for selecting gain (for full rail voltage swing on the outputs)

 

You can leave J1 out if you don't want to use any gain from the PGA blocks.


Edited by sachu - 5/18/10 at 6:58pm
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post #6 of 12
5/19/10 at 9:11am
Quote:
Originally Posted by sachu View Post

Marc is helping me behind the scene. 

 

It should work straight away but isn't for some reason. Marc is helping me nail down the issue. 

 

Actually studeb, there is all the info you need for the attenuator in the OP itself.

 

J2 is for selecting the encoder (so you definitely need this)

J1 is for selecting gain (for full rail voltage swing on the outputs)

 

You can leave J1 out if you don't want to use any gain from the PGA blocks.



OP?

Where? I have looked, but not found one. Mine came out of the eXStata thread.

Glad to hear there is maker support available.

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post #7 of 12
5/19/10 at 9:26am
Thread Starter 

The first post of this thread studeb...explains where the encoder pins go.

 

Now you know what the Jumpers do as well. That's everything.

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post #8 of 12
5/19/10 at 9:58am

sorry, i was thinking that "OP" was in another thread for this somewhere else.

i had worked out the encoder pins from the board traces, and i figured one jumper was gain, but could not get them worked out.

Thanks again.

Any progress with yours?

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post #9 of 12
6/8/10 at 4:49pm

i scored one of these without a lot of info when i bought an exstata board.  where's the original thread for this attenuator?  i cant seem to figure out anything about it....

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post #10 of 12
6/8/10 at 5:03pm
Thread Starter 

all info is on this thread...what are you having problems with? 

 

I am having problems cause either the uC that came with the board wasn't programmed or that i might have killed the micro controller unknowingly. Otherwise it should work easy enough.

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post #11 of 12
6/8/10 at 5:11pm

you dont happen to have any pictures of the board...  i bought the exstata and the guy threw this board in with a spread sheet that contained all the parts, but thats all the info i have.  i havent been able to find anything else about it.  currently, my issue is that the proper din jack doesnt fit in the board.  not enough holes.  its just.. disconcerting.. to not have any information to fall back on about it.

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post #12 of 12
6/8/10 at 5:16pm
Thread Starter 

The board didn't come with any PGA2320 digital potentiometer ICs or the programmed Atmel micro controller (this is the main part really)  ??

 

Send me a PM and i will forward the schematic over to you. If you have all the parts it is just a matter of stuffing really. The DIN connector isn't really necessary..you could just as well solder the power supply wires directly.


Edited by sachu - 6/8/10 at 5:18pm
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