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error, where is my problem?
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error, where is my problem?

by multisync on Fri Jun 01, 2007 12:03 pm

Okay,

I have started building X0xb0x. I've installed the resistors and capacitors, then I was going back to install the active compnants and testing as I went. All the tests on the power supply were within range until I got to measuring the jumper connections on J4. I measure Pin1 3.11V and Pin 3 7.69V...

Twisting the trim pot does not bring these numbers anywhere near in range.

Any thoughts as to where I foobarred?

Pete
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by adafruit on Fri Jun 01, 2007 12:06 pm

did you go through and perform each test of the power supply from the beginning?

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by multisync on Fri Jun 01, 2007 8:44 pm

Yes, the tests priot to the tests of J4 were all well within the proper range.

I grounded my meter for the test of J4 on the resistor next to the jumper, precisely where it was suggested. I will go through them again tomorrow, but I am certain that the tests prior to that one were correct..... I am thinking, I will also double check componant values and solder connections... any other ideas of what to look for?

--p
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by guest on Sat Jun 02, 2007 5:07 am

what are the voltages
on all of the pins of the opamp
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Voltages at pins of the 6562 OpAmp

by multisync on Sun Jun 03, 2007 1:21 pm

Pin 1: 7.68V
Pin 2: 3.10V
Pin 3: 3.10V
Pin 4: 0.00-0.01V
Pin 5: 3.09V
Pin 6: 3.10V
Pin 7: 3.10V
Pin 8: 28.1V

J4 Pin 1: 3.10V
J4 Pin 2: 0.01V
J4 Pin 3: 7.67V

--P
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by guest on Mon Jun 04, 2007 4:47 am

the problem is somewhere
in the voltage reference section
check to see that ic22 is the correct part
and is in correctly
and that r2 and r3 are the right values

also
the powersupply voltage is a bit high
are you using the stock wallwart
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fixed the problem... almost.

by multisync on Fri Jul 20, 2007 6:07 pm

R3 WAS WRONG. I keep messing up those orange versus red bands. They are a little ambiguous when I printed out the manual. I went through the kit and soldered in all the resistors first (as I like to do) and I think with the first few I was screwing up the orange and red bands in the X10^x section....

Anyhooo...

So I fixed it and I can get 5.33V exactly.

BUT my other voltage is 13.18 volts.

My AC adaptor is not original. I bought my kit second hand, and had to purchase a rat shack AC adaptor. It puts out about 10.4V at the 9V section...

Is this going to screw me or can I go ahead and keep going?

--P
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by guest on Sat Jul 21, 2007 1:12 am

double check r178 and r179
those control the 12v
the 13.8v wont hurt anything
but it will probably alter the sound
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Now What?!

by multisync on Sun Jul 22, 2007 6:10 pm

Okay, so I completed most of the kit, checked the analogue side out and everything was working (I was able to fire a note by manually connecting the gate, the cutoff and rez knobs altered it as expected)...

Then I let it sit overnight and today I disconnected the power supply in order to check MY LED intensity using the 5.333V as an approximate 5V supply... and pick out resistors to match the pretty coloured LEDs I bought.

Well I checked the voltages on the supply lines and got

10.9V instead of 5.33V
0V
25.5V instead of 12V

and if I checked for AC, the voltages were roughly twice that...

I assume some sort of part is fried and I need to order something to replace a piece of my power supply... but where do I start? any idea why it fried?

--Pete
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by guest on Mon Jul 23, 2007 7:41 am

your multimeter might be bad
its a bit odd that everything doubled
try measuring the voltage on a 9v battery
to see if the meter is calibrated
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Coming Back

by multisync on Tue May 13, 2008 10:42 pm

I chose to come back to this project. I still cannot figure out what's wrong with this power supply. Everything is as I left it about a year ago.

I checked resistors R178 and R179 and they are correct. R1 - R4 are also correct. With 10.4V AC attached to the power in jack I read on Jumper 4 11.1V on Pin 1 and 25.7V on Pin 3.

The problem began after I soldered in all the components on the I/O board as per the fabrication manual on Ladyada.net.

I checked a AAA cell at 1.59V and I worked on a MIDIBOX Core module last night and the 5V outputs were precisely where they should be. I think I can rule out the meter.

Any Suggestions? Should I replace the 6562? Are there possible culprits for gremlins in the I/O board, maybe some kind of short? There's nothing obvious in my soldering....

--Pete
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by guest on Wed May 14, 2008 2:55 pm

what are all the votlages on the opamp
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Op AMP Pin Voltages...

by multisync on Wed May 14, 2008 9:24 pm

All Numbers are Volts DC from my meter.

1 ) 25.7
2 ) 10.4
3 ) 11.0
4 ) 0
5 ) 11.0
6 ) 11.0
7 ) 11.0
8 ) 27.2
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by guest on Wed May 14, 2008 11:18 pm

your lm336 is broken
or r2 or r3 are wrong or shorted
what is the voltage at the r2 and r3 juncture
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R2, R3 Juncture...

by multisync on Thu May 15, 2008 12:12 am

26.1V at R2, R3 Juncture.

I believe that they are the correct value.

If it's the LM336, any idea how I fried it?

Wow, whoever this "guest" is, sure has rocked with the answers to these questions...

Thanks a million!

--Pete
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Please be positive and constructive with your questions and comments.