Small Clone copy questions...

[jimladladlooklike]

Hey pals,

I've started building a copy of the EHX Small Clone from the layout below:



Currently soldering in the resistors and I'm missing a few: 12k, 20k, 39k, 120k, 180k. Could I replace these with the nearest value I can find or do they have to be exact?

Cheers!

[mth5044]

Could you post a schematic? How far away are your nearest values?

[jimladladlooklike]

Hmm I could post a similar one. It is different in places but was the closest thing I could find. There was no schematic on tag board effects where I pulled the layout from.

I have 10k, 22k, 33k, 100k and 220k

[antonis]

It's a rather complicated board for trace so better get right resistor values..

You probably didn't proceed to caps populating or it should be more than peculiar to have 2.7nF cap handy and not 12k/120k resistor.. 

[jimladladlooklike]

Haha! Actually I began soldering what cap values I had, but you're right; I don't have 2u7 and quite a few of the other rarer values and will have to get them too I guess.

Thanks for the help and I will report back, hopefully with a working pedal!

Jim

[jimladladlooklike]

Slowly making progress with this one. However, I've just noticed that I have DPDT switches and the layout includes an LED. Is there a way I can omit the LED from the build altogether as it's not something I'm particularly fussed about.

Thanks!

[antonis]

Of course you can omit the LED, if you don't mind for status indication a lot..

Or you can build a smal daughterboard for Millenium by-pass of any version you like....

[jimladladlooklike]

By that do you mean I could literally just not connect the LED?

Thanks!

[antonis]

Yeappp..!!

As far as I can trace, you can also omit 2k2 current limiting resistor..
(the one with it's upper leg set between LED+ white wire and 2 holes left strip cut..)

[jimladladlooklike]

Awesome, thanks!

So I've finished building it with the LED omitted and a DPDT switch. However, when the effect is engaged I get a more treble but no chorus effect... time to debug!

All parts are the same as specified in the layout.

Voltages: (IC1 IC2 etc etc are listed in relation to the vero layout - not the schematic.)

Positive terminal on DC socket measuring at 9.1v

IC1
1: 4.4v
2: 4.4v
3: 3.5v
4: 0v
5: 4.3v
6: 4.4v
7: 4.4v
8: 9.1v

IC2
1: 7v
2: 3.4v
3: 0.2v
4: 0v
5: 0v
6: 0.6v
7: 0.5v
8: 0.5v

IC3
1: 7v
2: 0v
3: 5.9v
4: 7.1v
5: 7.1v
6: 7.1v
7: 0v
8: 0v
9: 0v
10: 0.8v
11: 3.5v
12: 0v
13: 7v
14: 0v

IC4
1: 7.8v
2: 2.1v
3: 1.2v
4: 0v
5: 3.8v
6: 4.1v
7: 6.1v
8: 9v

Q1
C: 0v
B: 4.3v
E: 4.8v

Q2
C: 9.1v
B: 0.4v
E: 0v

Q3
C: 9.1v
B: 7.8v
E: 7.1v

D1
A: 5.2v
K: 4.9v

D2
A: 0v
K: 3.7v  (weird?)

[ElectricDruid]

Q1 looks weird. In the wrong way around, maybe?

[antonis]

D2
A: 0v
K: 3.7v  (weird?)

Indeed..!!

But weird also 300mV forward voltage drop on D1 1N4148 Si diode..

[ElectricDruid]

Q1 looks weird. In the wrong way around, maybe?

My mistake -it's a PNP of course. That's why it looks like it's back to front...doh 

[jimladladlooklike]

D2
A: 0v
K: 3.7v  (weird?)

Indeed..!!

But weird also 300mV forward voltage drop on D1 1N4148 Si diode..

Thanks for pointing that out. What does this mean though? I literally have no idea how to approach debugging this one!

[jimladladlooklike]

Anyone care to take a look at this? Still have no clue where to start debugging.

Thanks in advance!