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DIY Stompboxes => Building your own stompbox => Topic started by: SM on March 19, 2004, 09:16:19 AM

Title: Problem solved modded SD 1
Post by: SM on March 19, 2004, 09:16:19 AM
Some weeks ago I described problems with a modded SD-1.
I had problems with oscillation and a lot of noise.
I removed, checked and reinstalled almost every component in the hunt for a solution but the problem remained.

I found the solution â€" it was my solder tin (is that the right description?). When soldering, it left a small brownish residue. The residue did transmit some (sort of) signal/electricity, resulting in the crackling noises and oscillation. After removing all residues with a toothbrush and some solvent the problem was gone!!

It took me some time to find the problem solution for this one and I thought I wanted to share this with you.

:-)
Bjorn
Title: Problem solved modded SD 1
Post by: Axmanjr on March 19, 2004, 02:41:14 PM
Way to go! :lol:   I'm still debating whether it's worth it to mod my pedal.
Title: Problem solved modded SD 1
Post by: parkerboy on March 19, 2004, 09:00:13 PM
I 'm a newb to this forum...any forum really, if you can't tell. But, I modded mine to the Keeley Ultra specs...To say the least it is incredible. WAY better than stock. Very tubey with the second LED switched in, like a big fat Marshall Stack. Great sustain and as much, or as little gain as you want. If you crank the distortion above 3 o'clock you get some really wicked, almost uncontrollable feedback.
Title: Problem solved modded SD 1
Post by: LH on March 20, 2004, 02:55:59 AM
So flux residue was the problem? I thought most resin fluxes were non-conductive and non-corrosive at normal temperatures.
Title: Problem solved modded SD 1
Post by: parkerboy on March 20, 2004, 08:45:46 AM
Oops. Wrong topic...thought it said DS-1...I'll use dyslexia as my excuse.
Title: Problem solved modded SD 1
Post by: SM on March 20, 2004, 09:16:07 AM
Quote from: LHSo flux residue was the problem? I thought most resin fluxes were non-conductive and non-corrosive at normal temperatures.


Yes,
I discovered it when i slaughtered the opamp in my Xotic RC. When installing the IC socket the RC started to crackle the same way as the SD1. When removing the residue the crackle disappeared.
Not so easy fix as it was hard to discover.

The unit sounds OK after modding and including a germanium diode but I would like some more presence.

:-)
bjorn
Title: Interesting...
Post by: petemoore on March 20, 2004, 11:33:23 AM
I use RS solder, it leaves a 'fair' amount of brown 'oil' that's sometimes between two holes of perf, and never had any noise problems.
 I think there's been testing done on this matter [just because the MFr's and users would test I think] but the only results I know of are you're post and this post.
 How conductive .Is. the core substance in RS solder ???
 That's what I"m wondering today...
Title: Re: Interesting...
Post by: SM on March 20, 2004, 11:51:47 AM
Quote from: petemooreI use RS solder, it leaves a 'fair' amount of brown 'oil' that's sometimes between two holes of perf, and never had any noise problems.
 I think there's been testing done on this matter [just because the MFr's and users would test I think] but the only results I know of are you're post and this post.
 How conductive .Is. the core substance in RS solder ???
 That's what I"m wondering today...


I’ve used this solder for years without any problems (or maybe some of the problems I’ve encountered were because of this…hmmm).

In these two cases (the SD1 and RC) the trouble causing evidence is irrefutable.

The solder I used was a fairly thin thread with 60% tin and 40% led (I think) and some resin.

:-)
Bjorn
Title: Re: Interesting...
Post by: LH on March 20, 2004, 01:33:10 PM
Quote from: petemooreI use RS solder, it leaves a 'fair' amount of brown 'oil' that's sometimes between two holes of perf, and never had any noise problems.
 I think there's been testing done on this matter [just because the MFr's and users would test I think] but the only results I know of are you're post and this post.
 How conductive .Is. the core substance in RS solder ???
 That's what I"m wondering today...

Someone told me that RadioShack solder is relabeled Kester solder. According to Kester, their "44" resin flux is non-conductive and non-corrosive at normal temperatures. But still, there have been lots of people that insist on removing flux residue, while others say it isn't necessary...
Title: Problem solved modded SD 1
Post by: Peter Snowberg on March 20, 2004, 01:40:40 PM
"Virgin" flux is non-conductive, but once you heat it up and it breaks down things change quite a bit. Just about any organic molecule will decompose into contaminated carbon at several hundred degrees. Super high impedance circuits won't work at all unless you remove the flux.

Take care,
-Peter
Title: Problem solved modded SD 1
Post by: puretube on March 20, 2004, 01:45:09 PM
I haven`t noticed any probs with flux even in "hot" tube circuits;
but it`s possible, that tiny little metall parts get "glued" between 2 pins by the flux...
even more probable, tiny splinters of (conducting)carbon from the solder-iron are glued there. (clean yer tips!)


edit:Peter: hadn`t read your post while writing this one...
Title: Problem solved modded SD 1
Post by: Peter Snowberg on March 20, 2004, 01:50:00 PM
to add one more thing.... When I say super high impedance above, I'm talking about data acquisition gear where you can see 100M input impedances or other super sensitive equipment.

Take care,
-Peter
Title: Problem solved modded SD 1
Post by: keko on March 21, 2004, 03:10:10 AM
I've been using a tooth brush to clean each pad as I solder it, so my boards (perf now, in favor of pcb) are much cleaner.

What kind of solvent can I use to further clean my solder work? I have several old boards that did'nt work and would like to bring'em back. I'm suspicious iver that brown oil.
Title: Ok
Post by: petemoore on March 21, 2004, 12:42:39 PM
I liked the test conditions SM, that's why I'm paying heed and lending my curiosities to this.
 At the very least [it would seem] the cleaned board is less likely to have foreign substances of solid [condensed smoky gasses like from smoke[ ]or any other type[ stick to the board.
 Plus resin just 'looks bad' to 'casual' observers.
 {it IS Sticky after all...]
Title: Problem solved modded SD 1
Post by: javacody on March 21, 2004, 12:46:58 PM
I use just plain jane soap and water to remove flux.

Don't most manufacters also bathe their boards to remove flux? There must  be a good reason for this.
Title: Problem solved modded SD 1
Post by: SM on March 22, 2004, 06:35:36 PM
Quote from: javacodyI use just plain jane soap and water to remove flux.

Don't most manufacters also bathe their boards to remove flux? There must  be a good reason for this.

I used a mix of alcohol and naphtha (Swedish â€" I don’t know the correct English word â€" paint remover). Works excellently.

:-)
Bjorn