Build Your Own Clone Message Board

the third band on my GEQ does not work. third from the right. if the controls from right to left were: pre-volume, very highs, pretty highs, sorta highs, high mids, sorta high mids, etc. it would be my "sorta highs"

i adjust the slider and NO tonal difference. everything else works great. where should i look?

look at the caps for that freq...since the rest of the pedal works its a good chance its a bad joint or cap in that position.

I just finished mine and it all works...but I went really, really, really, really slow. Some of those parts are hard to get at with the iron...

that's part of the problem. i don't know which caps correspond to that slider.

Did you even look at the schematic? It's pretty self explanatory if you look at it closely. Each slider is labeled as to what frequency it is. The rest should be easy to figure out from there.

It's SO much easier than you think. Take a component, any component, and just trace it along with the schematic. The lines on the schematic from component to component are the same as traces on the pcb.

Go to pin 1 of ICa for example. It is connected to capacitors C7 & C8. The other end of C7 is connected to slider VR4 which is the slider for 300Hz.

Do the same thing for whichever slider you're having trouble with and trace it out. Once you get the hang of it you won't believe how easy it actually is.

The cool thing about this pedal is it is extremely easy to locate your cold joint. The in and out buffer are on ICA. So if that's working, you can get sound without any of the freqs "working". If one of the freqs are dead, it doesn't kill the whole pedal, only that freq doesn't work.

If freq 3 is not working, then look at the 2 pins of the IC, the 2 caps, and the slider that are on that frequency.

Read the "selecting frequency" part of the instructions and it will tell you which caps you should look at. The schematic tells you you need to look at pins 1 and 3 of ICA.

take a look at the last page in the instructions, it tells you the caps that go with each freq value.

i have gone over the solder joints and relpaced the 560pf cap that are important to this frequency, but i still do not get any response when i adjust this slider. i have inspected and touched up the pins on the IC, pins 1 and 3. still no affect to the frequency. i may have to do more meddling.

just to verify, the cap values should be 560pf and .022uf, right?

just a thought, if you get no change whatsoever when you move that slider, take that one out and test it, maybe the slider is dead? either that or its a problem with the chip. even if you had different cap values on there you should be able to hear a change(granted that the frequency is in the human range of hearing)

The value of the caps isn't important as to whether or not it works. Maybe it is the slider. I seriously doubt that part of the chip would work while another part does not. That's not the nature of an IC.

I have the same problem. 2 of the sliders have no effect and the 1 in between only works way at the top. I'm gonna start a separate thread.

i will attempt to swap sliders and see if that helps.

Thanks Keith. It's gonna be a pain tearing that thing half apart to get the chip out. All those little pins! lol

Could it be both chips or can I just replace the one?

It would be nice to have a socket to fit this chip.

I sent some sockets. But there's really nothing that I know of that fits a ZIP18 very well. 2 SIP9 sockets do the trick, but they don't hold them in very tight....maybe tack it down with some hot glue or something so it doesn't fall out.

Thanks again! The sliders that do work sound great! Can't wait to see it at it's full potential! Still not looking forward to tearing it half apart.

i already did it once. it's not too bad.

update:

Problem: ok, so i had one slider that was not getting any response. since the cap values were correct and i was certain that there weren't any solder issues there were two possible problems: 1) the slider was bad, or 2) the IC was bad (which would be wierd for the entire IC to work except one frequency). so i figured i'd take a go at both problems at once. but a question arose: how to test both problems at the same time (so i don't have to take it all apart twice)?

Solution: i came upon a 2-part solution. in order to test the slider, i would swap it with another slider, once that i was sure was working. in order to test the chip, i would unmount the chip and install two sip9 sockets, so i can easily pop in different chips (easy since keith sent me two spares). if it was the chip, then installing a new chip would cause everything to work properly. if it was the slider, then the bum slider would be on a different frequency. simple enough.

result: rediculous! i moved the sliders (had to unsintall 5 to get at the IC properly), making sure that the allegedly bad slider was in a different position. i plugged the IC into the socket and fired it up. you'll never believe what happened: it was worse than before! before only one frequency didn't work. now, 3 frequencies didn't work, but the one that didn't work before now worked. aarg! i took a closer look and realized that i had stupidly put the IC in backwords. i had put it in properly, but accidently pulled it out and didn't pay as much attention the second time. anyway, once i noticed the misplaced chip, i quickly flipped it and gave it another go. guess what? same problem. "well," i thought "maybe plugging the chip in backwards killed it (like in a screamer). good thing i have the other chip!" so i tried the other chip. guess what? same problem!

kieth, if i mail it to you can you fix it?!!?

well. That sucks. I sent you two new chips and tested every channel on them. So unless these are hyper ESD sensitive and you were shuffling around a shag carpet with your socks on while wearing a wool sweater, I think we can rule out the chip as being the problem....based on your results. Hopefully leader will have better luck.

You should have tested the slider in question with a DMM.

So all three chips produce the same effect? 3 dead channels?

since i had two chips, when i pulled the original, i didn't think i would need it, so i cut it out, then desoldered the legs.

i did the whole "set it aside and come back later with fresh eyes" thing. my problem is deffinetely the slider. i emailed keith.

I pulled out the sliders in question and all mine work. I am having a bitch of a time pulling the chip. After 2 hours I had to put it down.

since keith sent me two replacement chips, i just cut out the old one, and removed the legs separetely. destroyed a chip, but worked.

I never want to do that again!

So I removed 3 sliders and they tested fine. I cut the legs from the chip that was giving me dead freqs. I spent a long time with some copper braid cleaning up the eyelets. What an ugly mess. I thought I messed the board up good. I installed the sockets and the chip kept falling out. I bent the pins so it would grab the socket a bit and gave it a shot of hot glue. I tried it out with the thing just hanging out of the enclosure and IT WORKS!!!!

Looks like I had a bad chip! Tomorrow I will clean it up and fix some melted wires and stuff and stick it back in the enclosure. one of the sliders is grabbing so I need to raise it a bit. What a nightmare. It's kinda satisfying in a way. I was pissed when it didn't work cause it sounded so good even with the dead freqs and I wanted to see the full potential. It was by far my most frustrating build as far as repairing it. I was worried after the problems fuzzy had. What a pain in the ass! These boards are top notch to be able to take the abuse I just put it through! Thanks again Keith!

Good luck fuzzy. Pedal sound killer!

Mine has a hiss, that is just too loud...don't know where it's coming from...happening at the input volume I think....

I notice a hiss in mine too, on par with what I used to get from my GE7. I'm not an audiophile, so I can live with it in most situations....I wouldn't record with it.