Ben,
Yeah, and unfortunately I have no other I/V solution to check. For all I know, everything is working fine and it's my I/V and buffer stage.
Cheers,
Greg
Yeah, and unfortunately I have no other I/V solution to check. For all I know, everything is working fine and it's my I/V and buffer stage.
Cheers,
Greg
You can put in a large IV resistor in each channel, say 150 ohms or higher, and see if you get any output.
I use only an IV resistor with no other stage. My preamp and amp have enough voltage gain.
I use only an IV resistor with no other stage. My preamp and amp have enough voltage gain.
Ben,
Okay, I can do that.
So, just hooking up the I2s directly:
C-1 > D3
Data > Data L or R?
LRCK > LE
BCLK > BCK
Cheers,
Greg
I don't have access to my computer right now so it is hard for me to view the schematics. So try DL and if it doesn't work try DR.
I just checked the schematics. DLeft is I2S data.
Do you have another I2S input dac to check the Singer?
If not, and if all three of your Singer, Simultaneous board, and D3 are not proven to be in working order, then it would be tough to determine what is not working.
Without an oscilloscope, I suppose you can check the Singer by checking for voltage out of the I2S pins.
For your D3, you can check that you are getting the correct voltages to the power pins on the TDA1541A. Check the schematics for the power pins and voltages on the TDA.
I see that Ryan's schematic does not show -15V on pin 15 of the TDA, but that is where it is at. 26 is -5V and 28 is +5V.
Do you have another I2S input dac to check the Singer?
If not, and if all three of your Singer, Simultaneous board, and D3 are not proven to be in working order, then it would be tough to determine what is not working.
Without an oscilloscope, I suppose you can check the Singer by checking for voltage out of the I2S pins.
For your D3, you can check that you are getting the correct voltages to the power pins on the TDA1541A. Check the schematics for the power pins and voltages on the TDA.
I see that Ryan's schematic does not show -15V on pin 15 of the TDA, but that is where it is at. 26 is -5V and 28 is +5V.
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Ben,
Awesome. No, on another DAC. Yes on access to a scope at a buddies house.
Thank you very much.
Awesome. No, on another DAC. Yes on access to a scope at a buddies house.
Thank you very much.
Went directly out with R35 populated. I'm hearing noise from the D3 with everything else disconnected. I've got serious problems. I think it's my D3.
Ryan, Haven't checked voltages yet on the D3 board. Have check the Simul. board and it's good.
Will do so tomorrow.
Cheers,
Greg
Ben / Ryan,
Okay, I found a voltage problem: Pin 28 on the dac socket only reads ~2.85v, not 5!
Pin 26 is exactly -5.01v. Also, pin 27 is at -5.0v1, this pin sets the data input.
Questions:
1. What should pin 27 voltage and polarity be? did I damage my chip with my messed up vreg on pin 28. I'm thinking since it's low, probably not?)
2. How do I get pin 28 up to 5v from 2.8v?
3. I'm measuring chip socket voltages with the chip out, is this correct? Or should the chip be installed for proper voltage readings due to load?
Cheers!
Greg
Okay, I found a voltage problem: Pin 28 on the dac socket only reads ~2.85v, not 5!
Pin 26 is exactly -5.01v. Also, pin 27 is at -5.0v1, this pin sets the data input.
Questions:
1. What should pin 27 voltage and polarity be? did I damage my chip with my messed up vreg on pin 28. I'm thinking since it's low, probably not?)
2. How do I get pin 28 up to 5v from 2.8v?
3. I'm measuring chip socket voltages with the chip out, is this correct? Or should the chip be installed for proper voltage readings due to load?
Cheers!
Greg
Ben / Ryan:
Cap voltages:
C10 : 26vdc
C15 : 5.01vdc
C7 : 2.89vdc
C11 : 23.4vdc
C19 : 15.25vdc
C22 : 20.2vdc
V1 :Ground to output : 2.57vdc
CC1 : Ground to output : 1.44vdc
Cheers,
Greg
Cap voltages:
C10 : 26vdc
C15 : 5.01vdc
C7 : 2.89vdc
C11 : 23.4vdc
C19 : 15.25vdc
C22 : 20.2vdc
V1 :Ground to output : 2.57vdc
CC1 : Ground to output : 1.44vdc
Cheers,
Greg
Ben / Ryan,
Looks like I overvolted my chip at pin 15. I'm measuring -20vdc!!! With a max -vdd2 of 16. Probably blown.
Cheers,
Greg
Looks like I overvolted my chip at pin 15. I'm measuring -20vdc!!! With a max -vdd2 of 16. Probably blown.
Cheers,
Greg
Hi Greg,
How did you get such high voltages? Hopefully your chip is ok.
Normally when im testing the board I use dummy loads.
Lately the first thing I solder on the D3 board is the minimum amount of parts to get the 3 supplies working, so if there is something wrong there aren't many parts the check/replace/reflow.
Solder these first, then test -
X1, X2, X3, C5, C13, C21,
R19, R20, R18, R24, R23, R25, R28, R30, R27, R29, R21, R17, R16
Q3, Q2, Q1, CC1, V1, R22.
Once these parts are in place I place the dummy load into the dip-28 socket holes and then power it up. If all is well your current should be around 135mA. If I have an issue I usually inspect all the solder joints. Then I re-flow the suspect joints using a little bit of flux.
Without the caps in place the supply voltages wont be accurate or stable but they should be close enough to verify operation.
Since I've started using this method my success rate of the circuit working first go is much better.
One other issue I've noticed that comes up sometimes is some fluxes need to be thoroughly cleaned off before testing or they affect the operation of the circuit.
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Ryan,
I have no idea how my pin 15 got to 20vdc. The board is already totally populated. I can try cleaning it again, but I did a thorough cleaning after it was built.
Pin 28 is low and 15 is way hi. Any ideas?
I have no idea how my pin 15 got to 20vdc. The board is already totally populated. I can try cleaning it again, but I did a thorough cleaning after it was built.
Pin 28 is low and 15 is way hi. Any ideas?
I would be re-flowing the solder joints with some flux on x1, x2, and x3 first. Then do the same for all the surrounding resistors. Save your 1541 and use dummy loads.
One other issue i've come across a few times is that if you overheat the polycaps when soldering they can leak much more current and they heat up. Sometimes they pull enough current to pull the voltage low.
With a high voltage on pin 15 i'd say the voltage reference isn't accurate for the TL431. Most likely a bad solder joint.
Also check the legs on all the PNPs (Q3...)
One other issue i've come across a few times is that if you overheat the polycaps when soldering they can leak much more current and they heat up. Sometimes they pull enough current to pull the voltage low.
With a high voltage on pin 15 i'd say the voltage reference isn't accurate for the TL431. Most likely a bad solder joint.
Also check the legs on all the PNPs (Q3...)
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I was really careful with the poly caps. The chip was a little warm, but never went cold. Hopefully it survived. I think I should order a spare. But, its an S1, so big bucks. But the supply is so low. Should I order a spare?
I will try those things.
I will try those things.
If you were careful when soldering them then they are probably ok. 95% of the time its a dry solder joint in the circuit somewhere.
Ryan,
Nothing looks dry. Just went over everything with a high power magnified loop. Also, re-cleaned the board.
When the board is cold, voltages are correct for -15 and +5. Then voltages drift very quickly (low for the +5, high for the -15 and good on the -5). So, maybe I over heated x-1, 2, 3?
Nothing looks dry. Just went over everything with a high power magnified loop. Also, re-cleaned the board.
When the board is cold, voltages are correct for -15 and +5. Then voltages drift very quickly (low for the +5, high for the -15 and good on the -5). So, maybe I over heated x-1, 2, 3?