AHH!!! Why is it always the last think you think of!!!

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AHH!!! Why is it always the last think you think of!!!

rocket88
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just had to vent. so like frank with the cold solder joints, i've been running into an issue that's been driving me literally up a wall. for those that don't know i'm a teacher, and throughout the year when things get crazy with state exams, finals, midterms, end of the semester things come up i have 0 time to relax and build or play music at all. so since school ended two weeks ago i've been on a building spree in between weddings, and family functions. between yesterday and about 5 minutes ago i just build 5 pedals in the and everything runs smoothly except for the hiccup.

instead of having issues with the occasional cold solder joint, or bridge between tracks i get transistor issues. i check them with my dca55 and they test fine, i put them in and the pedal doesn't work. i check with the tester again, and still says its good. after pulling my hair out trying to figure it out i put in another transistor and it works. so i start to analyze the transistor that didn't work and i notice that my dca says the pinout is different then it should be according to the datasheet. i'm finding, especially with some vintage Si transistors that the pinout is not always what it's supposed to be. they're not fake transistors, and everything tests within spec, but the pinout may be backwards or 2 pins are switched.

the second issue i've had, most recently with my modified rat, is i added a split n' blend for the first time, and since i didn't have any BF245's so i used 2n5457's. i power it up plug everything in and try it bypassed, works, hit the switch i get nothing but white noise. even turning the blend knob to be nothing but clean signal and still white noise. i check everything, cold solder joints, bridge, continuity, voltage, everything. i begin to think that there's something wrong with the split n' blend, and maybe the transistors are the issue. i check the pinout of the 2n5457 and realize that when they are installed the same way as the bf245's they are upside down. i switch them and it still didn't work right, then i find that one of them has an internal short.

i don't get it. the more i build the more stupid errors i have that take me forever to find because i think it has to be "_________." i never think of the obvious, and easiest things to check.

this had definitely cause me to rethink some of the ways i approach my builds. in particular i think that if you have a tester, like the dca55, TEST your transistors before you install them. this way you can check that they are good(no internal shorts), get the most accurate pinout rather then just trusting their position on the layout or from the datasheet, and if you want to match them or not you can.

sorry for the long, whiny post. i just had to vent and know you guys would understand and feel my pain. now at 2:25 in the afternoon and all this i need a beer, or two, or three.........

btw, all the pedals built sound freaking fantastic.
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Re: AHH!!! Why is it always the last think you think of!!!

dbat69
I feel your pain too - the DCA has saved me from a couple of "alternative" pinouts

I'll have a beer or six with ya
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Re: AHH!!! Why is it always the last think you think of!!!

bassbuddy
That's what happens if test equip gets too smart
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Re: AHH!!! Why is it always the last think you think of!!!

Frank_NH
Well, don't feel too bad - this is part of the challenge of DIY building.  

I have several builds (including my ROG Thor) that have problems.  When I get frustrated with them, I put them aside for another day, confident that I can eventually figure out the issue.  With the Thor, it seems that the voltages on one of the jfets are wrong, but I don't know where the problem is yet.  I'll find it...

However, another affliction that I have had is that a build actually works but...well, the sound isn't what I'd hoped for.  So I go on a modding spree!  For example I put a SWTC on the Hao Rust Driver and it instantly went from blah to wow (and hence it got boxed).  More recently, I just completed hot rodding the Subdecay Liquid Sunshine.  It is now an *awesome* pedal, capable of much more than just a "light" overdrive.  My main mod there was replacing the second gain pot with a fixed resistor and switchable caps (from 220nf up to 10 uF), to give me one gain control and a "mojo" switch (which increases the gain and bass by increasing the source resistor bypass cap value).  This configuration came after many days of experimentation in my pedal laboratory (ha ha ha )...  This pedal is now boxed.

At some point I am going to try to get some YouTube videos of these builds going, but one step at a time.

In the meantime - Keep on building!
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Re: AHH!!! Why is it always the last think you think of!!!

rocket88
Administrator
i know what you mean frank. i spent a few hours modifying my rangemaster. i wanted it to be more of a Ge full boost rather than treble boost. not it sounds awesome and i love it. trust me, i've built something like 50 or so since starting a few months ago, and there are only 2 that i can't seem to figure out, so my record is pretty good. its just the stupid stuff that kills ya, and when you try to explain it to someone who doesn't do what we do they look at you like your crazy, *cough* Ge Deathstar *cough*. so i figured i'ld vent to everyone here, cause i know i'm not the only one who has stupid problems and could use a good talk.

BTW, i'm 5 beers down, and changed my brakes in my car. now i think i should just rest and resume building tomorrow, but what to build........
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Re: AHH!!! Why is it always the last think you think of!!!

AC_FX
Ugh.  I feel ya.  I had one that really gave me fits this weekend, frustrating because it's a build I've done several times before.  On the plus side, getting it running gave me an idea for another look at one I'd given up on weeks ago, and I got that one working too.

Oh well.  It does feel good to resolve a problem through some logical troubleshooting, even though it sometimes feels like you missed the obvious.