Build Your Own Clone Message Board

I have built a Lazy Sprocket Rev 2.0 from a complete kit which I bought at a local store. I swapped the input and output jack sockets for other types, since I found that the ones provided touched the PCB when mounted in the enclosure, and I used colored wires instead of the purple wire provided with the kit.

I have tested the effect with a Stratocaster on a Fender Frontman 10G and a ROG Ruby amp. The bypass mode works and the LED comes on when the footswitch is pressed. The problem I experience is that there is hardly any output when the effect is engaged. I can hear some signal coming through only when my amplifier is turned up to the maximum. I do notice some of the effect in the output. The problem appears similar to some other topics (by gmcooper84, samber_dino). Following the instruction sheet and some of the advice given in those topics, I have tried the following so far:

1) I tried both a battery and a wall adapter. There was no difference.
2) I double checked that all the components are in the right place and reflowed all solder joints.
3) I measured all resistors while mounted in the PCB. All measured values matched the resistor values, except for:
3.a) the two 22k resistors on the bottom left of the board (R25 and R26?), which measure about 14k – this might be because they form a voltage divider? and
3.b) the 470k resistor (R4?). The resistance measured was only about 35 Ohms. I took out the resistor and tried to measure it, but I could not really get a good reading. It appears to measure about 390k. When measuring across the lugs on the board, I still measure about 35 Ohms. There does not appear to be any runaway solder, or other kind of short. Also looking at the schematic, I do not see a reason why this might be the case. Could there be an issue with the PCB?
4) The trimpot measures 8k8 Ohms, the b25k measures 24k2 and the A100K measures 101k5.
5) For the IC socket, I measured whether there was continuity between pin 3 and any of the other pins. There was none. The resistance between pin 3-4 was 234k; between 3-7 235k. Between pin3-2 there is a high initial measurement, which then changes to infinity after a second or so – is this normal and due to some capacitor?
6) I measured voltages at the IC pin 2=3.95V; pin 3=3.53V; pin 7 = 8.72V; pin 6 = 4.3V. The other pins measure 0V.
7) I measured the voltages at the JFET (which turned out to be faulty in two other topics): D=5.23, S=5.23, G=2.55. The value at G does not change when adjusting the trimpot.

Advice would be greatly appreciated!

Since I could not add more than 3 attachments, I omitted a photo of the switch (which works)

Several comments:

1. I don't see any components out of place, which is a common cause of low output.
2. You can't reliably measure resistor values when they're in a circuit because of the frequent presence of parallel circuit paths between your meter probes. Sometimes this works, depending upon what the resistor is connected to, but it will often give low resistance values, sometimes drastically so.
3. Your solder joint quality on the PCB looks excellent. On the jacks, not so much. Since your bypass signal works normally, I wouldn't worry about the I/O jacks. But I'd definitely try to improve the main + tab connection on the DC jack, which looks very poor.
4. The IC voltages look pretty good, though pins 2 & 3 are a bit low--I'd expect both to be up in the 4 - 4.5V range, like pin 6.
5. The gate voltage reading on the JFET seems very low. On my own Sprocket, I see 5.36V on both the drain & source, but the gate is up at 4.86V. Not sure if this would be a bad JFET or indicative of some other voltage problem in the circuit.
6. As you reported, the gate voltage of my JFET does not change with the trimpot setting.

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

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

Contact sales@buildyourownclone.com and request a replacement JFET. We are now sending out 2SK30A JFETs instead of the 2N5457. These have a different pinout. Please download the most recent instructions and they will explain how to orient the 2SK30A.

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*patience is a virtue*

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

Thank you very much for the quick replies. I will contact sales.

Sales has sent a K30 jfet my way, which I am waiting to arrive. In the meantime, I have managed to desolder and remove the 2N5457. I then put a 4x1 sip socket in its place and tried out a J113 jfet, which I had as a spare. The pedal worked immediately, albeit with a rather limited range. I hope that with the K30, this range increases. In any case, I'm glad to have found that the issue was indeed with the 2N5457.

As an aside: getting the 2N5457 out was extremely finicky and frustrating, and I found the risk of damaging the board is very high. It may be advisable for anyone building this pedal to use a socket, just in case!

I find it easier to just clip the unwanted transistor, heat up the solder joints, and then just pull the left over transistor legs out one at a time. It's a lot easier to desolder when the eyelets are empty.

_________________
*patience is a virtue*

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

I wish I'd thought of that, great idea!