First, I’m new to the forum and all that DIY stuff thanks for having me here!
Now to my problem: Last week, I built the Anushri readily and when I first powered it on, it gave some noisy, thin sound on the Line Out. After a night of troubleshooting I found out that the modular Audio Out works and sounds just fine, and only the Line Out still sounds thin and waaaay too low. Also, the volume knob doesn’t do anything. I double-checked that I installed the right pot and the right resistors in front and while measuring, I found out that the resistor R35 doesn’t measure 15k, but only 13k. The other ones measure 15k as they should, BTW. So here’s my question: could it be that the resistor is broken and causes the low output? If not, what else can I do to find out what’s wrong here?
I’d be very happy if anyone out here could give me some advice! Thanks in advance!
You can’t trust your resistor measurements if you measured while they were soldered - the total resistance of the circuit adds/detracts from the individual resistor, leading to wrong measurements.
Best bet for checking soldered resistors is to check the colour code…
What’s the soldering on the Line out, and the pot like?
If the resistor is broken, it would be black, and charred, and more importantly - not work, IE no sound at all…
It’s probably not something broken. Most of the times it’s a bad solder joint. Could you post a hires picture of both sides of both boards?
Thanks for your help! I just took some photos of both boards. You can find them here in full resolution:
Yesterday, I starred on both boards about an hour and even re-soldered a lot of the joints, but maybe I’m not experienced enough to see the problem. So thank you for any help!
I looked at the pictures and your soldering looks really good… I also looked at the schematics and between the modular audio out and the line output is only the volume pot and ofcourse the header where the signal goes back into the base PCB. So maybe your problem is at the pot…
But i also wonder if it could be just a bad jack cable you used?
Thanks for your input, shiftr!
I tried it with two different cables, so that shouldn’t be the problem.
Now I’ll have to go to bed, but tomorrow I’ll resolder the pot. Maybe this does the trick …
How can I check if the pot is broken?
Ah, another question: When I checked the connections with a continuity tester, I realised that one pin of the board interconnectors seems to be connected to the signal AND ground of the line out. As it’s really late and tomorrow’s a rather hard working day, I have to stop for now, but with a quick look, I couldn’t find any solder bridges or such which could cause the problem. Do you have any idea about what this could be? BTW, it’s the left of the two lying interconnectors, right under the midi sockets (when you look at the main board with the midi sockets on the upper left). It’s the fifth connector pin on the lower row, the one sitting between R12 and R13.
Any help appreciated!
The connector between the midi sockets caries the output signal I think… I’ll try to have a look at the schematics again today. The pot is probably fine… You could measure it withe the boards not attached. Remember that one pin is connected to ground.
There could be some problem under the board connection…
The point on the connector actually is a ground connection so that it has continuity with ground makes sense. It would also make sense that line out has continuity with ground if the volume pot is set to zero. Can you check it with the volume pot turned up?
Yes, I’ll check tonite and report back. Thanks again, shiftr!
Meanwhile, have a nice monday (if this is possible at all)
Thanks! I’m spending my day in the studio today
THIS is what I’d call a really good monday
Okay… Now I found out that the tip also connects to ground when the two boards are detached. So the problem has to be somewhere on the main board. Unfortunately, today I came home relatively late so I couldn’t unsolder anything to check. Maybe I’ll have to do this on weekend. Do you have any ideas?
So finally the problem disappeared after i resoldered the output plug. I suppose it actually was just a bad solder joint, as you thought! Thanks for your help, shiftr and V`cent!
BTW, I’ll post some pics of the finished Anushri here as soon as I finished the enclosure (I designed it myself):
Excellent news ! Congrats