AION Comet DS1 - sound is a low fuzz

[iainpunk]

Yes, I have a probe. The problem is am not sure what to test. The circuit works. Its is just a low fizzle. Like a bad cap or something. Or Bad IC. not sure...

left to right, listen how it sounds and report back about where it sounds good or where it sounds real bad.


cheers

[broomhandle]

Sorry, yes. Correct. The effect works. and the knobs does nothing. for the sound. Its more like a fuzz pedal.

[broomhandle]

Yes, I have a probe. The problem is am not sure what to test. The circuit works. Its is just a low fizzle. Like a bad cap or something. Or Bad IC. not sure...

left to right, listen how it sounds and report back about where it sounds good or where it sounds real bad.


cheers

would I be looking to see if the dist knob works?

[iainpunk]

Yes, I have a probe. The problem is am not sure what to test. The circuit works. Its is just a low fizzle. Like a bad cap or something. Or Bad IC. not sure...

left to right, listen how it sounds and report back about where it sounds good or where it sounds real bad.


cheers

would I be looking to see if the dist knob works?

mainly to follow the process of the sound being changed over and over to achieve the output signal. if there is something wrong somewhere, you can hear it through the probe, and that way isolate the problem, so it can be fixed without trial and error.

cheers

[broomhandle]

OK, so not sure if I did this correct. I followed the path, and checked each point. Amp into the probe (grounded). Guitar into the pedal. the pedal engaged. I got no sound out of each point. But a weird fuzz on D4 and D5 on the left side.

hope that was done correct.

[antonis]

I got no sound out of each point. But a weird fuzz on D4 and D5 on the left side.

Try to disconnect from VA (lift up) diode selector switch middle lug..

[broomhandle]

I got no sound out of each point. But a weird fuzz on D4 and D5 on the left side.

Try to disconnect from VA (lift up) diode selector switch middle lug..

could you rephrase that? I am not sure I understand.

multimeter on diode? and check the middle lug of the clip selector switch?

[antonis]

[broomhandle]

Sorry, but I still do not understand. ( I think you are saying cut out lug 2 on switch? I am not sure)

I am still a novice. I work in IT and can tear down and rebuild engines. But I am still learning with circuits.

I am not sure what you are asking me to do. Sorry I am having trouble with this one. I am really at a loss..

[iainpunk]

OK, so not sure if I did this correct. I followed the path, and checked each point. Amp into the probe (grounded). Guitar into the pedal. the pedal engaged. I got no sound out of each point. But a weird fuzz on D4 and D5 on the left side.

hope that was done correct.

either its done incorrectly or there is no signal at all arriving at the circuit's input.
with an audio probe, you clip the black wire on to the board ground and the red wire goes to the measure points
maybe audio probe the switch to see if signal even gets through it allright, then the wire between the switch and the board,
i added orange circles to test for signal as well:


we also need your DC voltages to be able to determine other faults.
the DC points of all transistor and chip pins.

cheers

[antonis]

Sorry, but I still do not understand. ( I think you are saying cut out lug 2 on switch? I am not sure)
[/quote

Leave diode pair(s) OPEN/ON AIR/NOT AC GROUNDED..
WE need to "isolate" diodes clippling configuration to find out their possible influence on (non-working) Gain pot..

P.S.
Forget it..
Just connected switch lug 2 to GND (on any convenient circuit point) instead of VA..

[broomhandle]

I tried this. I got a ground wire from ground to 2nd lug switch. = no sound nothing.

Sorry, but I still do not understand. ( I think you are saying cut out lug 2 on switch? I am not sure)
[/quote

Leave diode pair(s) OPEN/ON AIR/NOT AC GROUNDED..
WE need to "isolate" diodes clippling configuration to find out their possible influence on (non-working) Gain pot..

P.S.
Forget it..
Just connected switch lug 2 to GND (on any convenient circuit point) instead of VA..

[broomhandle]

I will do this and report back. The orange spots are the measure points for the switch?

OK, so not sure if I did this correct. I followed the path, and checked each point. Amp into the probe (grounded). Guitar into the pedal. the pedal engaged. I got no sound out of each point. But a weird fuzz on D4 and D5 on the left side.

hope that was done correct.

either its done incorrectly or there is no signal at all arriving at the circuit's input.
with an audio probe, you clip the black wire on to the board ground and the red wire goes to the measure points
maybe audio probe the switch to see if signal even gets through it allright, then the wire between the switch and the board,
i added orange circles to test for signal as well:


we also need your DC voltages to be able to determine other faults.
the DC points of all transistor and chip pins.

cheers

[broomhandle]

with the probe, effect engaged. I get a pass thru (no effect) on: RPD, R1, C1 and R2. Effect on the bottom lug on the switch.

..and DC volts. I can not get a reading on RPD and R1. But I get 4.33 on C1 and R2.

OK, so not sure if I did this correct. I followed the path, and checked each point. Amp into the probe (grounded). Guitar into the pedal. the pedal engaged. I got no sound out of each point. But a weird fuzz on D4 and D5 on the left side.

hope that was done correct.

either its done incorrectly or there is no signal at all arriving at the circuit's input.
with an audio probe, you clip the black wire on to the board ground and the red wire goes to the measure points
maybe audio probe the switch to see if signal even gets through it allright, then the wire between the switch and the board,
i added orange circles to test for signal as well:


we also need your DC voltages to be able to determine other faults.
the DC points of all transistor and chip pins.

cheers

[iainpunk]

FIRTS i would like you to measure the DC points
with the DC points i mean all pins of the chip and transistors, resistors and caps don't need a DC bias to work the way they should.

the orange test points are for confirmation that there is actually signal arriving at the Board. you'd be amazed how many people have trouble related to the off-board wiring, resulting in bad/no signal reaching/exiting the board. in your case, that's not the problem, so we look further through the circuit. i'd like you to report back with where the sound becomes bad/nonexistent/muffled in a bad way, its probably that point in the circuit where there is a fault

the next test point for the audio probe are the first transistor's 3 pins. ONE of those should be silent, and two of those should have clean guitar signal.

then we test the next transistor, one pin should be pure clean, one should have clean-ish guitar signal, and one should have way louder (slightly) distorted guitar signal.

after that we go to the op amp, pins 2 should have the aforementioned slightly distorted guitar signal, pin 3 should be dependent on DIST control setting, when its all the way down the signal should be the same as pin 2, but the higher you turn it the quieter and more distorted it should become.
pin 6 is also DIST setting sensitive, i should get more distorted and slightly louder when turned up.

the next point to test is the clipping diodes, test for sound at the red circle i posted earlier.

then the tone stack, all 3 red circles should have a ''filtered'' tone, one muffled, one bright and one dependent on the tone knob.

then you test the volume control lugs, one should be silent, one should have high volume and one should be setting dependent.

with the volume control fully loud, the output transistor: 2 pins should have distorted sound and one pin should be silent.

then R19 and R20, R19 should have sound on both sides and R20 only on one side.

if that all works, then you look at the output off board wiring.

i hope this ''guide'' helps you finding the problems
cheers, Iain