Harmonic Energizer debug

[kierkegaard]

now im no expert but im not sure Q1 ia operating properly after this debug

but i am hardly even a novice tbh, so any help is welcome!

i should add i lost a few pads during the build so have jumpers between

r15 and negative pin of c10 (sent to ground)
r14 and positive pin of c10 (followed marking on the board)
r7 (silkscreen side) and pin 13 of IC1 and C4  (followed markings on the board)


Here is the checklist to fill out:
1.What does it do, not do, and sound like?   Getting no signal from it, just silence
2.Name of the circuit = harmonic energizer
3.Source of the circuit (URL of schematic or project) =    https://shop.pedalparts.co.uk/Harmonic_Energiser/p847124_16145208.aspx
4.Any modifications to the circuit? NO
5.Any parts substitutions? -
6.Positive ground to negative ground conversion? unsure
7.Turn your meter on, set it to the 10V or 20V scale. Remove the battery from the battery clip. Probe the battery terminals with the meter leads before putting it in the clip. What is the out of circuit battery voltage? => 8.5v
Now insert the battery into the clip. If your effect is wired so that a plug must be in the input or output jack to turn the battery power on, insert one end of a cord into that jack. Connect the negative/black meter lead to signal ground by clipping the negative/black lead to the outer sleeve of the input or output jack, whichever does not have a plug in it. With the negative lead on signal ground, measure the following:

Voltage at the circuit board end of the red battery lead = 4.0v
Voltage at the circuit board end of the black battery lead =2.7mv

Now, using the original schematic as a reference for which part is which (that is, which transistor is Q1, Q2, etc. and which IC is IC1, IC2, C1, and so on) measure and list the voltage on each pin of every transistor and IC. Just keep the black lead on ground, and touch the pointed end of the red probe to each one in turn. Report the voltages as follows:

Q1
C = 1.16v
B =  0v
E =  0vd

Q2
C=  1.16v
B=  1.24v
E=   2.62v

IC1 (or U1)
P1   1.17v
P2   0.63v
P3   0.81v
P4   1.39v
P5   608mv
P6  717mv
P7   0.81v
P8   1.15v
P9   601mv
P10   604mv
P11   13mv
P12   608mv
P13   604mv
P14 1.17v

D1
A (anode, the non-band end) =3.958v
K (cathode, the banded end) = 2.968v

[mcknib]

You're better posting some pics, all of your voltages are way off D1 looks to be where your problems start with only 3.95v going in, that should be power supply voltage so it'll be having a knock on affect on the rest of the circuit i.e not getting your 4.5v VB or VA etc

Q1 is a mosfet so pins would be gate source drain like this

[kierkegaard]

so i built a circuit tester last night with a more reliable power source and redid it today

quite different results, the results at the diode at least look right to me, 0.7v loss at the cathode

gonna have to admit ignorance at what you wrote about Q1, i dont even really understand CBE

pictures here  http://imgur.com/gallery/c6A6Vuj

Q1
C = 0.9v
B =  0v
E =  0v

Q2
C=  0.9v
B=  1.09v
E=   8.3v

IC1 (or U1)
P1   0.9v
P2   300mvv
P3   0.76v
P4   1.03v
P5   500mv
P6  500mv
P7   0.77v
P8   1.05v
P9   470mv
P10   470mv
P11   13mv
P12   466mv
P13   470mv
P14 1.05v

D1
A (anode, the non-band end) = 8.3v
K (cathode, the banded end) = 9v

[niektb]

did you measure your battery (when disconnected from the circuit)?

[kierkegaard]

yeah the first lot of results are from a batter that measured 7.5v

this second lot of results are from this https://shop.pedalparts.co.uk/Circuit_Tester_Pumped/p847124_20113804.aspx

using a 9v supply for power, output of the tester is registering at 9.2v

[mcknib]

Your TL074 is in the wrong way round the notch should go to the top, turn that around, hopefully you've not fried it

I see it's got a notch and dot so easy mistake to make

[Marcos - Munky]

yeah the first lot of results are from a batter that measured 7.5v

You can call this battery as dead.

[kierkegaard]

Your TL074 is in the wrong way round the notch should go to the top, turn that around, hopefully you've not fried it

I see it's got a notch and dot so easy mistake to make

ah man i cant believe i missed that! i had another one so chucked that in its TL074CN not TL074IN

either way it still doesnt work unfortunately, with both chips there is a distinct amount of popping and crackline, when i do get it still i can hear the sound of a frequency sweeping high to low erraticaly, like the tuning of a radio or something

[mcknib]

Do you get 4.5v ish at the junction of R17 and 18

[kierkegaard]

nah hovering around 3V

[mcknib]

Should be half power supply VB there to bias the 074

Some of your readings are slightly confusing I'm thinking your Q2 E is yer C then what you've got coming out of the Emitter is low 0.9 which then via VA goes to Q1 Drain also 0.9! looks to me like you've got your transistors in the wrong place Q1 should be the 2N5458 and Q2 the 2N5088 from your pics it looks like you've got the 5088 in Q1

Obviously you're gonna have to swap them around, so if you've got a small croc clip, clip it onto the legs as a heatsink before you try to desolder them, too much heat will kill them

I've sent you a PM with a link to a beginners component guide PDF should help you get some insight

[kierkegaard]

yeah sorry im sure my readings are a mess, im getting my CBE by looking from the flat side and counting from the left 1/C  2/B  3/E

swapped them round by cliiping them off, then tidying up and resoldering, always find that easier

i really have made a massive mess of this one havent i, after a string of successes i got over confident

new readings as follows, still doest work, what do you think of my rewiring after losing some pads? it squeals when i go near those wires, like feedback i guess if my finger is shorting it somewhere?

Q1

C - 7.32v
B - 7.25v
E - 7.32v

Q2

C - 7.32v
B -  8v
E  - 8.5v

[mcknib]

I think you may have damaged your transistors

Albeit easier to check them out of circuit if you scroll down a tad on this page here it's got a bit about testing in circuit without power

https://learnabout-electronics.org/transistor_faults_06.php

With regard to your jumpers R7 looks like it's got a bit too much solder on it and you may only need 1 jumper there to C4 as long as C4 is then connected to pin 13

[kierkegaard]

That's a really handy link thank you, I think I'm gonna order some more transistors, I'll test these when I snip them off

Could having them in the wrong place have damaged them?

Looking at my transistor readings and reading that page certainly ly makes it seem like they are broken

How do you know what voltages you are looking for? I'm impressed and a little intimidated that you can tell where the problem is from these numbers!

[mcknib]

Don't be impressed my knowledge is basic

Fortunately for you and me as a member here we've got lot's of very knowledgable people

I use what I can from the schematic where you'll see points marked VA and VB in the power section top right, all of these points will be connected e.g. VA - Q2 E (Emitter) to Q1 D (drain) and pin 4 of the TL074 so you'd expect the same voltage at all these points you can calculate exactly what voltage to expect there using ohms law etc

VB (voltage bias) is normally but not always half the power supply around 4.5v you can see that VB starts at the junction of R17 and 18 both 10K which form a voltage divider to half the power supply with them both being the same resistance value it's an equal split, again you'd expect all the points marked VB to have half the power supply voltage so that gives you a start of what to expect and check

Now I've built lots of pedals so like everything else the more you do it the more you learn for example you'd know that most but not all op amps are biased at 4.5v so every pin on a op amp apart from (in your case) 4 power and 11 ground you'd expect 4.5v on each input and output pin yours being a quad op amp ie 4 in 1 package you'd have 4x inverting inputs (-), 4x non inverting inputs (+) and 4 x outputs IC1A, B, C and D in the schematic


Anyway there's a lot of reading to be done in this here hobby is what I'm trying to say, did you get the link to the PDF I PM'd you, have a read of that, if not here it is, as I said, done for and specific to gpcb boards but the same for any and not my work I basically compiled other peoples work into one doc for beginners so they didn't make the same mistakes I made like buying massive 600v caps way too big for pcb work and so on

https://drive.google.com/file/d/19YLa4VV8El4AvvKgRYb4i9NbKcdifi6V/view?usp=sharing

I as I say don't have a great knowledge just the basics to get me by, I've never seen a transistor like Q2 around the power section for example, so I couldn't tell you what it's being used for I know this is an old 70's effect so I'm assuming it's being used for something we don't need to use it for these days, a regulator? switch? variable resistor no idea, so in the pursuit of learning which is ongoing in this hobby I'm all ears if anybody cares to tell me