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I have never been able to get this pedal working and I have some time now so I thought I'd give it another try. I built it back in March of 2015. There is and old thread but decided to create a new one.

Bipass works and the LED lights when the foot switch is pressed (Voodoo labs power supply@ 9.34v)

Switch to Manual and there is signal, although a little weak (not quite unity volume). The manual knob works but the Range knob has no effect.

Switch to Envelope and there is no signal at all.

I’ve reflowed I think a couple of times now and its starting to look like it. I’ve attached photos.

Thanks……joe

Please take voltage readings of the 4558 chip.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

power on-LED on -Switch set to manual
1-4.66
2-4.66
3-2.3
4-0
5-3.99
6-4.35
7-4.62
8-9.31

Switch set to env. Voltage starts out the same as above then gradually drops to the levels below.
1-3.12
2-3.11
3-1.53
4-0
5-2.66
6-3.08
7-3.06
8-9.31

That's really weird. I don't understand how the manual switch could be affecting the 4558 voltages. Try removing the 13600 and take voltage readings of the 4558 again, please.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

With 13600 pulled-switched to Manual:

1-3.08
2-3.08
3-1.52
4-0
5-2.64
6-3.06
7-3.04
8-9.31

Voltages are the same and steady when switched to Env.

Pull the 4558 out and take readings of the empty 8 pin socket. You've probably got a bad 4558. If pins 3 and 5 jump up to around 4.5V when you take the chip out, that's probably what's going on.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

13600 and the 4558 pulled.

1-1.73
2-1.73
3-1.5
4-0
5-2.64
6-0
7-0
8-9.31

Voltages are the same in Env and in Manual.

Looking at the two photos of the solder side of your PCB, I'm concerned about the possibility of solder "bridging" between adjacent eyelets. Unless the eyelets are already joined with a trace on the PCB, this can easily lead to shorting and voltage loss. I would suggest that you carefully inspect that side of the board and clean up any such bridges that you find. I'd use some sort of magnifying device, if you have one available. I've circled some possible problems that I see in your photos that you should check out. I'd also recommend gently bending the Sensitivity and Attack pots up away from the PCB and inspect the solder joints underneath them for similar issues.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Thanks duhvoodooman for the fresh eyes.

I inspected and cleaned the board up with alcohol and found no bridges. I bent the pots up and inspected and cleaned underneath.
Here are a couple of fresh pics. Still a little cotton from the Qtip.

Based on your voltages, I can tell you with almost absolute certainty, that you have a short somewhere. Unfortunately, I can't tell you where it is. I have seen cases similar to this where there was nothing visibly obvious and it ended up being underneath the IC socket.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Is there a way to test continuity from each pin to something in lieu of desoldering both IC sockets?
Desolder and reinstall or is there some testing that can happen when they are both out?

Yes. You should have a continuity test on your meter

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

If I'm reading the schematic correctly, the only pins of the two IC's that should show continuity with each other are as follows:

4558: pins 1 & 2

13600: Pins 5 & 7; pins 10 & 12

UPDATE: Confirmed the above by continuity testing the sockets on my own EF/FW.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

4558 -IC pulled and checking the socket.
Pins 1&2 have continuity to each other
Pin 4 has continuity to ground.

13600 - IC pulled and checking the socket.
Pins 5&7 and Pins 10&12 have continuity to each other
Pin 6 has continuity to ground.

I checked all Pin locations to each other thinking a short under the socket would show up with a pin to pin or a pin to ground check.

Sockets are the easiest and cleanest soldering job on the whole build, however the hardest to desolder and get out. I would really like to check what I can before removal becomes the last resort.

Thanks.....joe

Based upon those continuity results, I'd leave the sockets as is--they look to be just fine.

The joint pair I've marked below still concerns me, because it sure looks like there's contact there. Suggest that you test for continuity/resistance between the two joints:



Even if no continuity, check the resistance between the two--could still have a partial power short, albeit not a "dead short."

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Yeah....If there's something that's only semi-conductive trapped under the socket, it wouldn't show up as "continuity" on your meter.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

I've Cleaned up the soldering on C12 (pic attached)

Before and after cleanup:

No continuity
Meter set on 20K - Gradual increase to 10.04K

Is this the way C12 should react while in the circuit?

No continuity
Meter set on 20K - Gradual increase to 10.04K

I'm not sure what to do at this point.

Yes, that agrees exactly with what I measure on my own EF/FW.

Yeah, I'm running out of ideas, too. If it was me, I'd be very tempted to just replace both IC's, but the LM13600 is an obsolete part and may be hard to find at a reasonable price. BYOC shows them as out of stock. Keith would know if the LM13700 would be a work-alike in this circuit. Digi-Key has those for a couple of bucks apiece.

One thing we haven't checked is the lead voltages of the transistor. Could you check those, just for the sake of completeness?

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

I'm not sure I'm doing this correctly but here is what I did to check the transistor.

Pedal Off:
E-27.2 Ohms
B-0
C-0

Pedal on (same reading with the switch in both env/man
E-9.31v
B-0
C-0

Thanks....

So, how do the transistor readings look?

Looks like the last resort is to replace the IC's.

Keith, Is the LM13700 a replacement for the LM13600?

Thanks......joe

A couple of comments here:

1) Why is your "Pedal off" emitter result reported as ohms?? Looking for DC voltage here.

2) When the pedal is in bypass, the power to the circuit is still on, as long as your power source is connected and there's a cable inserted into the input jack. The footswitch is not an on/off power switch; it just switches the effect circuit in and out of the signal path between your guitar and amp/output device.

3) Ignoring the ohms/volts confusion, the results still aren't right. For the transistor in my fully functional EF/FW:

C = 9.95V (same as my power source, to which it is directly connected in the circuit)
B = 1.26V
E = 0.84V

These values are constants withing a couple of hundredths of a volt whether or not the pedal is engaged or bypassed, auto or manual.

You need to get these transistor voltages sorted out before worrying about the 13600. The correct procedure for measuring the transistor voltages is as follows:

Set your multimeter to the DC voltage mode; use the 20VDC range setting if it's not an auto-ranging meter. Of course, your power source needs to be connected and there needs to be a cable in the input jack. If the pedal is assembled into the metal enclosure, put the black probe into one of the corner screw bosses of the enclosure--this is your ground connection. If the "guts" are out of the enclosure, use the sleeve tab of the input jack for the ground connection. Then touch the red probe to the test point that you want to measure and hold it there until the reading is stable within a couple of hundredths of a volt. Repeat the process for each leg of the transistor.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Thanks duhvoodooman

I may have got the names reversed for the transistor legs. I have attached a drawing that I used to report the voltages.

Meter on 20v setting.
There's a cable inserted into the input jack
Power plugged in and the LED burs bright
Guts are out and the ground attached to the sleeve tab of the input jack.

C=9.31V
B=0V -It started out with voltage reading of .04V then slowly drained down to zero.
E=0V

What are your voltages on the 3 attack pot eyelets?

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

I have both of the IC's pulled for the transistor voltage reading.

Could that make a difference?