Aionfx Vintage Distortion (Rat Clone). Troubleshooting

[boleiro]

Completed my rat clone build from AionFx and when plugging in... no joy. 

I definitely fried the LEDR on the footswitch board... I could smell the faint acrid smell upon powering on and the LEDR now has burn marks.  I used my MXR ISO Power Brick, 9v so I am not sure if this was a power thing or if some mistake I made in the install caused it.

I reinstalled another LEDR and still no joy.  But, it also didn't make that little fizzle sound or smell.  Not sure where to go from here.

Any advice and experience would be appreciated!

Here are my measurements at the IC:

Pin 1: 12.92
Pin 2: 6.37
Pin 3: 5.93
Pin 4: 0.00
Pin 5: 13.68
Pin 6: 14.04
Pin 7: 13.38
Pin 8: 0.00 

[GGBB]

Welcome.

The LEDR in the pic looks wrong - if the light band is white that resistor is 470Gohm which will not allow enough current for the LED to light up. (If it's silver it's a 4.7ohm which will fry.) If the first LEDR you tried fried, it was probably too low and you probably fried the LED along with it. Make sure you use the correct value resistor - measure them with your meter to be sure. Try a 4.7k to start - go higher if the LED is too bright. The LED problem does not affect the circuit.

As for the circuit - it appears you don't have the distortion pot connected - you need that. The sweep pot is also missing - this won't prevent the circuit from working but it will have a big impact on the sound.

Measure your power supply output - The MXR is capable of providing different voltage levels (my guess is that you're connecting to a 15V output).

[FiveseveN]

Hello and welcome!
You say you're feeding it 9V yet you measure 14V, how does that work?

[boleiro]

Hey GGBB... thanks for the quick reply!

The resistor used for the original installation and the replacement is a 4.7ohm as is called for... from the BOM/Build Notes: LEDR 4k7 Metal film resistor, 1/4W.

Looking at the resistor the band is silver confirming 4.7ohm.  If the LED was fried, would that short the signal?  I am getting no output. 

just remeasured the IC pins and may have figured out my mistake.  I used the wrong cable from my power brick and the output was 12v. remeasured with an actual 9v slot to get the readings below.  But that would explain the blown resistor.  PIN 1 is reading 7.88. 

Dumb. 

[antonis]

Welcome, also..

Just 2 minor notes about wiring..
Solid wires arent indicated for narrow area solder pads..
Lower gauge (thicker) wires should be used for ground paths..

P.S.
A 4.7Ohm resistor is 1000 times smaller than a 4k7 one..
(bye-bye LED..)

[boleiro]

Interesting... cats out of the bag, I'm a newb.

I ordered through Mouser using the part# on the BOM.  the Manufacturer and Mouser part# designates "4K7" but the product description shows a 4.7ohm resistor.  I thought the K was interchangeable with the decimal point... No?

Mfr. Part #
MFR-25FRF52-4K7
Mouser Part #
603-MFR-25FRF52-4K7
YAGEO   Metal Film Resistors - Through Hole 4.7K OHM 1/4W 1%

EDIT::
Just looked through my build notes and I see that mouser was back ordered so I had to order through Tayda.  I got 4.7 ohm and not 4.7 K Ohm.  So easy to mess up in this game.

[midwestrepairdesk]

a few things,

-C7 is missing from the board.
-you missed a solder point on one of the clipping diodes
-distortion pot not wired into board
-sweep pot not wired into board

The LED will have no effect on the pedals functionality whatsoever.

Good luck!

[boleiro]

thanks Midwest!

C7 was not needed if a Film cap was used in CX1... which I did of course knowing that Film caps are so much better!  Joking... only kind of:).

I'll look at your other observations and see if those get me up an running... Can't believe I didn't notice the distortion and sweep pots are not wired!

thank you!

[ElectricDruid]

I ordered through Mouser using the part# on the BOM.  the Manufacturer and Mouser part# designates "4K7" but the product description shows a 4.7ohm resistor.  I thought the K was interchangeable with the decimal point... No?

The K in "4K7" is like the K in "Y2K" and represents "thousands", so 4K7 is 4700 Ohms. Similarly, "M" is millions, so 4M7 is 4,700,000 ohms, 4.7 Megohms. You also see "R" used to make clear that there's *no* multiplier applied. So 47R is 47 ohms, 220R is 220 ohms, etc. 4.7 ohms would be 4R7 written like this, but I don't think I've ever seen a value that small.

So easy to mess up in this game.

Oh yes!!

HTH

[GGBB]

I thought the K was interchangeable with the decimal point... No?

The [digits][letter][digits] format is an alternative to regular decimal format for numbers. The letter which is a metric SI prefix takes the place of the decimal point. For example 4.7k = 4k7.

The K in "4K7" is like the K in "Y2K" and represents "thousands", so 4K7 is 4700 Ohms. Similarly, "M" is millions, so 4M7 is 4,700,000 ohms, 4.7 Megohms. You also see "R" used to make clear that there's *no* multiplier applied. So 47R is 47 ohms, 220R is 220 ohms, etc. 4.7 ohms would be 4R7 written like this, but I don't think I've ever seen a value that small.

Technically, "K" for "kilo" or thousands is a mistake commonly seen/understood at least in DIY stompbox circles. The correct prefix is lowercase "k". https://www.nist.gov/pml/owm/metric-si-prefixes

[duck_arse]

another welcome. but - please don't make us chase your build docs. always post them with the photos and voltages, otherwise we have no idea what we are looking at, OR what correct docs we need search for your build.

[boleiro]

I reviewed the designations last night.... a little late but helpful nonetheless. 

I have the build doc link below:

chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://aionfx.com/app/files/docs/helios_documentation.pdf

I'll send voltages when I get the 2 pots wired... still can't believe I missed connecting those! 

[PRR]

chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://aionfx.com/app/files/docs/helios_documentation.pdf

The Adobe extension efaidnbmnnnibpcajpcglclefindmkaj for Chrome seems to be a dangerous thing. I suggest you review reports like this one:
Adobe pushed insecure Adobe Acrobat extension to Chrome systems
https://www.ghacks.net/2017/01/21/adobe-pushed-insecure-adobe-acrobat-extension-to-chrome-systems/

A proper URL would be https://aionfx.com/app/files/docs/helios_documentation.pdf