Slow loris revision problem...

[BraindeadAudio]

I made 2 of them to double check I didnt do something wrong, I think there may be a problem with the boards themselves. I wired up one and all it does is oscilate, another one oscilates but then it dims the LED when I turn the volume knob? Checked everything and it all seems fine parts wise.

[madbean]

If the LED is dimming when you turn the volume knob, I would double check your wiring. Are you sure you have the PCB, DC jack, 3PDT and one of the jacks all grounded?

[mgwhit]

Are these boards etched or fabbed?  You've obviously got a solder bridge or a short between traces somewhere. 

After you've triple checked the wiring, if they still don't work please post your voltages at the pins of IC1 and Q1 and well-lit, in-focus, high-resolution photos of both sides of the board.

[BraindeadAudio]

Yep, everythings grounded and wired correctly. Im a RAT addict so Im wiring up a op07 version with germanium diodes, and a metal can LM308 version with UV Ultra Bright LEDs and germanium clipping that cascade into each other, in a big case with independent power supplys and input output jacks. sorta like a hopped up R2DU. The 1n4001 gets really hot and the sound is really quiet now, the 1n4001 isnt in backwards. , no grounding problems anywhere either. Ive made over 20+ pedals from Madbean and loved all of them, this is jut a tad confusing since I havent had a diode get hot like that before? Maybe I got a bad batch of 1n4001s from Mammoth?

[BraindeadAudio]

Also, they are fabbed boards

[oldhousescott]

The only way I can imagine D6 getting so hot is if the polarity of the 9v is backwards.

[BraindeadAudio]

Reflowed the boards, and now on one of them the Op amp is getting hot? Im thoroughly confused. Ill post pics tomorrow.

[jkokura]

Reflowing isn't necessarily going to be helpful until we know what kind of voltages you're getting. If you don't know how to take voltages, you'll need a voltmeter or a multi-meter. Connect your black probe to ground, then use your red probe to check:

+9V
GND
Pins 1-8 of all ICs
Pins 1-3 of all transistors.

Likely you're IC is getting hot because power is leaking to ground or you are feeding it with too much voltage.

Jacob

[BraindeadAudio]

As a quick test I just did before I can really sit down with them after work tonight, I hit the switch and the pedal gets power then quickly loses it, but its still oscilating in the mean time. I am also having a problem with one of my Mudbunnys not doing anything no matter what Diodes I put in for clipping, yet another one works fine? I am starting to think I got bad parts from Mammoth.

[madbean]

Bad parts happen less frequently than you might think. Of course, it is a possibility and therefore do not eliminate that as part of your debugging. But, consider other possible potential areas: incorrect values, incorrect transistor orientation or subs, bad power supply, etc. Most of what you are describing is pretty typical of "builds gone wrong" so I think you will be able to track down the issues with enough patience and thoroughness.

[BraindeadAudio]

I hear ya, Its always a learning EXP with these things, which is why I love doing it. Going to attack it in the AM and post what I find, and hopefully get it working.

[BraindeadAudio]

Ok heres what Im getting, IC 1-8 in this order,
1, 9.04,
2, 9.0,
3, 4.57,
4, 0,
5, 0,
6, 2.24,
7, 4.56,
8, 9.05.  
my transistor is reading 1-3, with 1 being at the bottom of the board,
1, 9.16,
2, 0,
and 3, 2.26.
 my +9v read 9.24 and the ground reads 0. an odd thing is my LED reads its getting 9.23 before the 4.7k as well as 9.18 after the 4.7k resistor? and 6.62 going into pin 1 of the 3PDT.

The R1 reads 0 on both ends, but the capacitor at C1 reads 2.24? How could that be if theres no reading on R1?



I thought possibly i could be losing power through the clipping switch as i get no reading on any pin, nor on the cut pot, and my R7 is reading 0.04, and C8 reading .03 and the R8 reading 2.22 at one side and 4.45 at the othere? Also the volume pot has 0 reading after the 1UF cap?

Any help is greatly appreciated as this is quite confusing.

[madbean]

Are you using a 308 for the IC? Some of those voltages are looking pretty off. Ti start, you should be seeing about 9v on pin7. I don't know how you could be getting 4.5 there but 9v on pins 1, 2 and 8.

You should expect to read 0v on the front end of the input cap and the back end of the output cap. These caps decouple the DC portion of the circuit from the AC guitar signal. You would actually be in trouble if you were reading voltage there!

[mgwhit]

I'm thinking you may have your pin numbers backwards.  Pin 1 is to the immediate left of the dimple and the numbers continue counter-clockwise around the chip until you reach pin 8 to the right of the dimple.

[BraindeadAudio]

Metal can LM308, and, yea your right I numbered em backwards haha. It is getting 9v at 1 and 8 though.