SOLVED Rodent problem

Idroj

Idroj

Active member
Hi! And this is the 3rd and for now, last faulty pedal I build. A RAT that, now that I remember, I got from Tayda, pcb included. I built it, and similar to the Blue Breaker, I was able to enjoy it for a few seconds and then nothing.. I took it out of the enclosure, used this system that this youtube explained to narrow down if the problem is in the pcb board or the wiring, and it only worked for a moment, sounded amazing, but just for those few seconds. Now that I fixed 2 pedals this week with your all your help, and learning lots of things, I guess that a good place to start would be a good cleaning, right? I'll also have to try to unplug some pads and re-wire the 3PDT switch board...

Should I reflow anything else or just start the IPA toothbrush cleaning and put it all back together?

If I get to fix this one, after having fixed the other 2, this will be a HUGE VICTORY! Thanks everyone for taking the time to help out!

IMG_7749.jpg IMG_7750.jpg IMG_7751.jpg IMG_7752.jpg Diagram to test PCBs b4 wiring.jpg
 
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Also, quick question, are these chips both common for other builds? I'm asking to decide if to get just 1 of each or several for future builds, since I'll probably have to pay a shipping fee..
 
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Chas Grant said:
Not at all! It is internally compensated. With OP07 the 30 pF cap is not needed. With the 308N you can change the slew rate with the cap size.
Click to expand...
Interesting. I checked the data sheet and agree. Doing a google search I see lots of misconception about this (which is what led me astray). I see some people claiming it requires external compensation. Some claiming it doesn't, but that by adding the capacitor it can change the slew rate to match an lm308 (which, I don't see anything in the data sheet suggesting that it would, so I figure that's BS?), and others say it's not necessary.

Given that the data sheet should be the source of truth and it's not needed, I wonder why ProCo still puts the cap in RATs once they switched. Does it serve any purpose, or is it there to accommodate the IC swappers?
 
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Idroj said:
Also, quick question, are these chips both common for other builds? I'm asking to decide if to get just 1 of each or several for future builds, since I'll probably have to pay a shipping fee..
Click to expand...
Get the 308N from Jameco, no reason to not go with original. Its pricey but not to bad, I have found them from $3 to $5. Also Jameco is a bigger outfit, so it should be legit. As far as common goes, not really. There are a few circuits based on these that call for the 308 but not many. I would get a1 or 2 extra just incase, but thats me.
 
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spi said:
Given that the data sheet should be the source of truth and it's not needed, I wonder why ProCo still puts the cap in RATs once they switched. Does it serve any purpose, or is it there to accommodate the IC swappers?
Click to expand...
IC swappers and uniformed individuals. Proco knows a lot of people buy the new ones with the intention of replacing the OP07, leaving the cap in the circuit helps sales on this. Otherwise why not just build one from a pcb up, Like we do.
 
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Chas Grant said:
Get the 308N from Jameco, no reason to not go with original. Its pricey but not to bad, I have found them from $3 to $5. Also Jameco is a bigger outfit, so it should be legit. As far as common goes, not really. There are a few circuits based on these that call for the 308 but not many. I would get a1 or 2 extra just incase, but thats me.
Click to expand...
Oh, so Jameco is the original manufacturer for this particular chip? Also, where do you recommend I get all my parts? I've been getting everything exclusively from Tayda. And one other question: Today I received a new adj temp iron, what is the ideal temp for pedals?
 
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Now, I have another 5 pcbs coming my way, I have a little stock of parts from previous tayda orders, and I'm wondering what is the best workflow:

1. Print all 5 build docs, look for what I already have and scratch it out of the BOMs and put is in 5 separate bags, and whatever I'm missing add to the cart?

2. Print all 5 build docs, add EVERYTHING to the tayda cart from the BOMs, and then look for what I already have and take it off the cart?

It can get messy because of multiples of 10, etc.. Are there some particularly helpful tips to prepare and order? Maybe enter everything I need on an excel spreadsheet and look at inventory and eliminate what I already have?

How do you guys normally do it?
 
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Idroj said:
1. Print all 5 build docs, look for what I already have and scratch it out of the BOMs and put is in 5 separate bags, and whatever I'm missing add to the cart?
Click to expand...

I write all the components I need for a pedal on a piece of paper, and then tape the components to the page.
The bigger parts like pots and ICs go in a baggie.
I track missing parts in a spreadsheet, and when I make orders I check the spreadsheet.

IMG_20201202_092158859.jpg
 
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Now that I see those box film caps, every time i pull them from the tape they come stuck on, I'm always afraid I'll brake the legs from the box.. and always end up removing the tape with fingernails.. a pain.. they come really taped there..
 
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I’m totally different than above. I have drawers of parts. They are all organized according to type and size. When I decided to build a certain pedal I check inventory and order what I’m short of, always ordering more than I need. Then when I build I just pull the parts as needed. (Less mess for me) All parts are inventoried on spreadsheets also. Most of the time I only need to order a strange size pot .??? Yes I have a pedal problem.

Tayda is great for most things, you can’t beat their prices on pots resistors and caps, and they are good quantities. So I order a lot from them. I also use Mouser, Love My Switches, Small Bear, Stomp Box Parts and others. If you need some crazy stuff a lot of the amplifier sites are great. They carry a lot of germanium and carbon comp resistors and other stuff. Most have pedal stuff also.
 
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Chas Grant said:
I’m totally different than above. I have drawers of parts. They are all organized according to type and size. When I decided to build a certain pedal I check inventory and order what I’m short of, always ordering more than I need. Then when I build I just pull the parts as needed. (Less mess for me) All parts are inventoried on spreadsheets also. Most of the time I only need to order a strange size pot .??? Yes I have a pedal problem.

Tayda is great for most things, you can’t beat their prices on pots resistors and caps, and they are good quantities. So I order a lot from them. I also use Mouser, Love My Switches, Small Bear, Stomp Box Parts and others. If you need some crazy stuff a lot of the amplifier sites are great. They carry a lot of germanium and carbon comp resistors and other stuff. Most have pedal stuff also.
Click to expand...
Awesome! thanks!
 
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I'll try the two approaches. This is working for now! I ended up choosing PAL800 for next build. Quick question: what are these resistor values on R8 and R11 with the R instead of K?

BOM organization 1.JPG
 
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Idroj said:
Now that I see those box film caps, every time i pull them from the tape they come stuck on, I'm always afraid I'll brake the legs from the box.. and always end up removing the tape with fingernails.. a pain.. they come really taped there..
Click to expand...
I clip them off with wire clippers.
 
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Idroj said:
Oh, so Jameco is the original manufacturer for this particular chip? Also, where do you recommend I get all my parts? I've been getting everything exclusively from Tayda. And one other question: Today I received a new adj temp iron, what is the ideal temp for pedals?
Click to expand...
Nope, the orginal is the 308N, Futurelec has the 301N, a good replacement and close to the 308N. But if you can get a 308N stay with the original. I think Motorola was the original manufacturer. They quit making them years ago. A few other companies made them and continued production past Motorola, that's what we are getting now. You may see them marked as uA308N also, same chip different manufacturer, really good though. And vary rare.
 
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