My latest hobby...

[Frank_NH]

So...what do you do after building dozens of vero effects?  Well, in my case, having gained a ton of knowledge on debugging non-working effects, it seemed natural to branch out into fixing old broken effects pedals!  

I've been purchasing these broken pedals on eBay and Reverb.com for usually no more than $30 or so.  For now I'm sticking to old analog effects (no DSP or even SMD analog), which are easier to work with due to the size of the components.  So far, I've been able to fix all of the broken effects I've obtained, and my gallery is pictured below.  I'll describe each and how they were fixed:

(1) Carvin T-01 Tube Overdrive

This was the first effect I fixed, and I wanted to trace it as well.  It turned out to be a copy of the Boss SD-1, but it sounds nice and the effect is built like a tank.  The problem with this one was a bad volume pot.  Since all of the pots were pretty poor (cheapest pots you could use, apparently), I replace them all with good quality alpha equivalents.  It works great now, and is a keeper as it sounds a bit different than a standard tube screamer due to differences in the tone section and the asymmetric clipping diodes.

(2) Ibanez RC99 Chorus

I got this one cheap as it wasn't working at all.  I soon found out why - the previous owner had accidentally used the wrong polarity power supply and not only fried the protection diode, but also took out the power supply 100 uF cap, all three of the dual op amps, and the NE571 compander.   I methodically went through this, checking voltages, and when I replaced the compander - boom, it work!   I also, noticed some ticking due to the close proximity of the controls to the main circuit board, and was able to fix that by making a shield from aluminum foil sandwich between thin pieces of plastic.  Don't really know why that helped so much, but the effect is silent now.    This is probably another keeper - it really sounds good and is quite versatile.

(3) MXR Dynacomp

These are built like tanks as well, and when I opened this up I found that the previous own had (somehow) broken both control pots !  Fortunately, the main PCB wasn't damaged, and all that was needed were two (somewhat difficult to source) PCB-mounted pots to get it going again.  I'm using this now with my rig as it seems to work well in front of overdrives to smooth single note leads.

(4) DW Labs D3P Multi Distortion

This was a real find!  I couldn't locate any info on this pedal (apparently only made for a short time in the 90s), and it turned out to be a really easy fix - just one leg of the tone pot was unsoldered.  A quick resolder and a cleaning the pots and it's as good as new.  I am trying to trace this, but it's difficult.  The effect is quite interesting in that the four way switch (second from left) allows you to select drive levels from a simple preamp to tube screamer (Blues), distortion (Rock), and a big muff-like fuzz (Metal).  All of the distortions sound great, particularly the Rock and Metal settings.  Also, changing the switch affects how the tone control works for each setting (hence some of the complexity in tracing it).  It's also a very quiet effect, and uses two quad op amps.  At least three of the op amps are simple buffers, while the others are used for various gain stages with what appears to be hard clipping diodes (i.e. diodes are not in the op amp feedback loop).  Anyways, I hope to trace it completely at some point, but I want to USE it right now, so I'll save tracing for another day!

I have another effect on the way - an analog flanger.  That should be interesting...

[PMowdes]

Nice work.  I recently acquired a faulty dunlop bass wah (i wanted the enclosure for a Krog MrMulti clone).  I figured i might be able to salvage the pcb as well.  when i opened it up it was all SMD.

I think the wrong power supply was plugged in because half the board was fried and loads of the tracks had lifted.  Shame it was SMD otherwise i might have been able to save it.  At least the enclosure went to good use.

[Frank_NH]

Yeah, on the RC99, the diode itself was completely charred and there was a dark spot on the PCB where the burning occurred.  Fortunately, the traces in the area survived.

This was a parallel protection diode arrangement, which makes me think that a series protection diode is the probably better way to go if you really want to protect the circuit.

[Travis]

Awesome! Nice work Frank

I have gotten some great pedals this way. FZ-1A, Mutron Phasor II, Crybaby, Small Stone, Memory Man, etc

Love that feeling of finding something really cool for cheap and bringing it back to life

[Frank_NH]

Travis wrote

Awesome! Nice work Frank

I have gotten some great pedals this way. FZ-1A, Mutron Phasor II, Crybaby, Small Stone, Memory Man, etc

Love that feeling of finding something really cool for cheap and bringing it back to life

Yes, especially old analog effects which may otherwise end up in a landfill somewhere.  If an effect is too far gone, you can always harvest components and the enclosure.  But, sometimes you get a real diamond in the rough.  That's the case with the Mutli Distortion pedal - it really sounds good!!  Hope to trace it completely, in due course...

[M. Spencer]

Yeah, me too! Learning how to build the circuits from scratch and read a schematic gave me the confidence to go through my milk crate of broken or malfunctioning gear.

So far I've repaired a 10 series Ibanez Super Metal (a real diamond in the rough distortion, the SM9 had been a mainstay of my rig), Digitech Bass Synth Wah, Dunlop Stereo Tremolo, Line6 DL4, vintage Roland Space Echo and Dearmomd Volume pedal, Maxon AF9 Auto Filter, Peavey DDL3, and rehouse a DOD FX90 and FX65.

It makes me feel like a champion!