Help with a Ruby

Ultra Spidey · July 14, 2007, 02:43:34 PM

I've built a Ruby and it's quite dead. No signal comes through. I tried probing around and I get no signal at all. I'm using a DC adapter, which is OK since i've tried it with other projects. I'm using a 9V supply. I'm using a TIS74 for the buffer part instead of a MPF102. Yes, I did check the pinout. I didn't find any cold solder joints.

Project page:
http://www.runoffgroove.com/ruby.html

Voltages at the transistor:
Gate: 0v
Source: 3v
Drain: 12v

Pictures of the circuit:

CGDARK · July 14, 2007, 02:52:15 PM

Begin with cutting the excess of the components leads at the bottom of the board. Maybe there's an unwanted jumper.

CG

Ultra Spidey · July 14, 2007, 03:06:02 PM

Still not working..

CGDARK · July 14, 2007, 03:22:36 PM

Check the cuts that you made to the strips under the IC, maybe there's a short and by the way solder the IC to the board it is not soldered as I can see and maybe there's not contact at all of the IC with the rest of the circuit.

CG

Ultra Spidey · July 14, 2007, 03:23:42 PM

It has contact, I checked with my multimeter. And it's not shorting in any place.

oskar · July 14, 2007, 03:58:40 PM

No, it isn't solder.
solder it.

CGDARK · July 14, 2007, 04:06:30 PM

Recheck all joints carefully and in detail with the schematic (do not assume anything for debugging). Check with your DMM for shorts and solder bridges. Looking at the second photo, there's a little mess of wires in there, keep them separated just to be sure. I have a question, What speaker are you using?

Are you sure that it is OK? If all joints and parts are where they belong and in good condition then you have a bad IC, a bad speaker or both, because you said that your power supply is OK

. Remember debugging is the hard part of DIY, but at the end it's worth the effort.

CG

Barcode80 · July 14, 2007, 04:21:51 PM

you really need to solder in all the parts.

Apehouse · July 14, 2007, 04:34:01 PM

Quote from: Ultra Spidey on July 14, 2007, 02:43:34 PM
I've built a Ruby and it's quite dead. No signal comes through. I tried probing around and I get no signal at all.

I'm confused. Are you using an audio probe? If so, you should have a signal at the input of your board. If you don't have a signal there then you must first figure out why your signal isn't making it from the guitar to the effect. If you do, then you should be able to follow it till you dont have a signal and maybe that will narrow it down. I would also recomend finishing the soldering as well. And maybe use a socket in case the chip is bad.

-Greg

ambulancevoice · July 14, 2007, 08:43:59 PM

how did you handle the ic

Ultra Spidey · July 14, 2007, 09:55:38 PM

Thank you all for answering

At first I used a socket for the IC, and it didn't work. So I figured bypassing the socket would eliminate the option of it being faulty. I placed the IC on the veroboard and bent the leads so it'll have contact and stay in place, just for debugging. It has contact, I checked it several times and it always had contact.
I don't have an audio probe. I just touched along the line of the input to see whether I get any signal. How hard it is to make an audio probe? Is that the cable connected to the amp on one end, and to parts of the circuit on the other?
There are no shorts and no unwanted bridges, I triple checked it.
I did not try to change a speaker, I haven't thought of it. I'll do so tomorrow.
How do I test for a faulty IC?

And again, thank you all for helping

Apehouse · July 14, 2007, 11:11:28 PM

Quote from: Ultra Spidey on July 14, 2007, 09:55:38 PM
Thank you all for answering

I don't have an audio probe. I just touched along the line of the input to see whether I get any signal. How hard it is to make an audio probe? Is that the cable connected to the amp on one end, and to parts of the circuit on the other?

How do I test for a faulty IC?

And again, thank you all for helping

audio probe details can be found here:
http://www.diystompboxes.com/wiki/index.php?title=Debugging

and this is pretty much required reading when debugging:
http://www.geofex.com/fxdebug/fxdebug.htm
(as is his entire site!)

the audio probe is fairly simple and amazing. i usually record a simple guitar riff and loop it on a recorder or my computer and then feed that into the input of non-working effect. if the effect were working properly the recorded guitar sound would be properly altered by the effect and come out the output as it should, but when an effect isn't working you can use an audio probe to follow the sound through the circuit to find out where it stops working. Also very educational, even on a working effect, because you get to hear how the different parts of the circuit affect the original sound.

As frustrating as it can feel, i think we learn more about effect building from troubleshooting than the actual building. at least i think i do.

-Greg

Barcode80 · July 14, 2007, 11:47:40 PM

also, it is hard to ee from the pictures, did you actually cut any strips under the IC? because you are supposed to...

ambulancevoice · July 15, 2007, 12:06:58 AM

did you ground yourself when handling the ic? cause the 386 is static sensitive

hahah, i just noticed, under your ic, your supposed the cut the tracks bettween the ics pins
you havnt
just cut the tracks under the ic to stop the connection between the pins

ambulancevoice · July 15, 2007, 12:15:56 AM

the red dots are the tracks to cut
you can use a 5 mm drill bit, and just twist it to and fro and it will eat away the copper
or you can use a xacto knife

the thing i circled in red, is that supposed to be connected?

Ultra Spidey · July 15, 2007, 02:56:54 AM

I did cut those tracks. And that blob is supposed to be connected.

Alas, I haven't grounded myself when handling the IC. I'll test with a probe to see if I killed it.

Thanks

ambulancevoice · July 15, 2007, 04:03:12 AM

also, i recomend that you do use the socket
cause with direct soldering, comes the risk of frying the ic with excess heat

oskar · July 15, 2007, 04:53:31 AM

Even if you CAN get ESD dammages to a component it isn't very likely. Even if you do get ESD dammages on
a component it wouldn't necessary go flat out dead, it could as well mean higher noise or some other
degradation of its's function/specs. ESD is absolutely a reality but applies more to industry where you
statistically can see improvements in production after taking meassures against it. You're component COULD
be dammaged, but it most likely ISN'T.

You really need to...
1. Use a socket AND solder it to the board. It does make a difference. Don't argue, just do it.
The first thing you learn on a solder course is... A solder joint is an ELECTRIC connection NOT
a MECHANIC!
You have added resistances on all the inputs and I'm not going to bother looking up the datasheet for that
component if you don't bother to connect it properly.
Solder in a socket and plug her into it.
2. The +9V cable don't look properly soldered.
3. The thing sticking out to the right is that the output coupling cap? Is there more things you haven't connected?
you can test a circuit with some parts not soldered. Basically you strum a chord on the guitar and then start
poking... but then you should know you're making exponential laws (murphys law) work for you.
Faults dont add up... they multiply!!!
4. Meassure the voltage of the power supply again, first without load and then with the circuit connected.
You had a voltage reading of 15 volts there. That's a bit high.

--- best of luck!!

oskar

XinTX · July 16, 2007, 12:37:41 AM

Maybe it's just the way I laid out my circuit, but the transistor looks like it's mounted backwards to me. Check that.

Iron Code Monkey · July 16, 2007, 01:47:03 PM

It looks like you're using metal, non-insulated wire to hook up the pots. You need to use insulated wire for the pots. Otherwise the pots will twist and the wires will short-circuit.
Second, it's been mentioned already, but you really should use sockets for both the IC and the transistor. ALL semiconductors - IC's, transistors, diodes, and LEDs - are very heat sensitive. They tend to break internally when you solder without a heatsink. Sockets alleviate this problem entirely, and let you try different components to get different sounds. There are dozens of different JFETs you might try in there, and a few different ICs too.
Last, try using a verified board layout, and be very systematic about construction. Cut the track breaks first.. then insert sockets.. then resistors.. caps.. then pots and wires. Check the layout gallery and do a search for TheBigMan, he has a Ruby layout you might want to try before you start improvising your own. Alternatively, you might try buying a ready-to-solder PCB from General Guitar Gadgets, or ask for one in the For-Sale section. That will alleviate most of your frustrations with building.

News:

Help with a Ruby