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Messages - RobW

#1
Thanks for the clarification on that.
Working on calibration next, so I think I'm good now  8)
#2
The documentation for this project says to use a 12v power supply.
However, when I power up the PCB using 12v, and check the voltages on the IC's, all of the measurements are high.
When I use a check the voltages using a 9v power supply, the IC voltages are all within the range listed in the project documentation.
Has anyone had a similar issue with their build?
#3
As always, thanks for the input from those of you that have been down his path once or twice !
I'm currently working on the Touchstone Chorus, and was pretty careful with this one.
Checked values on all caps and resistors before putting them in place, and discarded any part that was really far out of spec.
BTW.. .that was something else I picked up in the forum, and really appreciate!
The problem I'm having is that IC2 ( the MN3007 chip ) values are pretty far off for pins 3, 7, 8.
I started testing values, and this post relates to R24 in the build, which should be 180k.
The after insert/solder value is less than half of that, roughly 94k , so It appears something is wrong.... just not sure what.
Should I just replace R24 at continue troubleshooting at that point?
Or is a different approach better?

Again, thanks for the input   8)

#4
Just found my own answer.
For other idiot beginners like me out there, you cannot have power going to the board.
That's what I was doing wrong.
#5
This probably seems very simple to most experienced builders, but I'm having a heck of a time trying to check the values of resistors on a board I'm troubleshooting.
Is there some trick to this? I have 2 different DMM's, and can get readings from the IC chips without problem.
Any suggestions on this? I've tried multiple settings on the DMM's but nothing works.
Any help on this would be appreciated.
thanks !
#6
Thanks Brian,
I checked the measurements with the chip in as well, and the measurements were similar to what I posted.
I'll check the resistor values you mention as well to see if that resolves the issue.
I'm fairly new to pedal building, and have lots to learn about the troubleshooting part of this.
So thanks for the advice!
I've received a lot of great feedback in the forum so far.
Nice to have a place to go for problem solving.
#7
Having a bit of trouble with voltages on one of the chips in this build.
Here's what I have for IC2 - MN3007
Position --- should be --- I get this
1 --- 8.49 --- 8.38
2 --- 4.2 --- 4.1
3 --- 4.1 --- 1.2
4 --- 0 --- 0
5 --- 0 --- 0
6 --- 4.2 --- 4.1
7 --- 3.99 --- 8.25
8 --- 3.99 --- 8.25

these measurements are all taken without the chip in, so I don't think it's the chip itself.
Any suggestions on how to correct the issues with pins 3, 7, and 8 ?
#8
Open Discussion / Re: Suggestions for a newby
April 29, 2021, 06:36:01 AM
Thanks for the suggestion on the breadboard, and also all of the other suggestions so far. One of the challenging parts of this for me so far has been what to pick. There are so many choices when you start searching the web... anything from pcb's to buy or all of the components and tools you need... it's good to get some good suggestions on places to use as sources for material.
#9
Open Discussion / Re: Suggestions for a newby
April 27, 2021, 01:51:08 PM
the breadboard is also a new concept to me... I've heard them mentioned enough in various information I'm reading online, but have no knowledge of how important they are, or how easy/hard it is to set one up. Reading up on that is probably a good place to spend some time.
Thanks for the info on the tolerances as well.. I plan on getting a component reader and since I'm buying resistors and caps in bulk ( nothing crazy,, if i need 2, i'll get 20 ... plus the cost of them is minimal ), I can use ones that test with the closest value.
#10
Open Discussion / Re: Suggestions for a newby
April 27, 2021, 12:45:03 PM
I do have a DMM.. So far it sounds like the Audio probe and component reader are must haves.
Another question for you all...
I've been sourcing parts from Tayda, Small Bear, Mouser, and a few others..
What I've been finding is that the tolerances on many caps and resistors are +-5% or +-10%.
In a build that calls for a 47nf capacitor for example.. if the cap only tests at 43nf due to the tolerance variance, will that cause issues with the build?
I'm trying to be aware of those things, but also wondering if it's really not that big of a concern.
#11
Open Discussion / Re: Suggestions for a newby
April 27, 2021, 09:24:59 AM
Thanks for all the suggestions so far! Great to get tips from you guys who have already been down this rabbit hole. The more I look, I'm finding there's a whole lot more to learn.
#12
Open Discussion / Suggestions for a newby
April 27, 2021, 08:34:06 AM
I'm pretty new to pedal building, and looking for advice. Many of the projects I look at suggest having an Oscilloscope, and/or audio probe as part of your general tools to work with. Any suggestions on what are good items to get for a beginner? I'd rather get something good, than take the cheap path, but don't want to break the bank either. I've never used either one, so it would be helpful to get something that is user friendly if possible. Thanks ! Rob