Need help troubleshooting HM2 kit gone bad

[amaurythewarrior]

Hello,
I built my first kit, a HM2 clone from musikding,
https://www.musikding.de/The-HMTwo-Distortion-kit
https://www.musikding.de/docs/musikding/hmtwo/hm2_schalt.pdf

and I did a solid state mic preamp, which not a kit, 10 years ago, more complicated, and works.

However I did a very stupid mistake, I plugged the PSU from my whammy, which I never realized was AC...
So, the PSU fried, not sure it is the correct term in English, but it doesn't work anymore.
I tried powering the pedal with a battery, which sound like this:
https://soundcloud.com/amaurythewarrior/hm2problem

The noise is linked to the "high" pot, but stops after removing IC2 (TL072)
However, even without IC2 it sounds terrible.
https://soundcloud.com/amaurythewarrior/hm2problem2
I tried replacing all ICs with spare NE5532 which I had, shows no improvement.
Worst case scenario is I'll buy all parts again, but if anyone is more competent, maybe it's possible to narrow it down?
Thanks in advance.

[amaurythewarrior]

Just incase
here is a gutshot
https://imgur.com/a/KS2z6ef

[11-90-an]

Welcome to the forum...

How much does your whammy psu supply? (I.e. how many volts)

Do you have any extras for C6 and C12, C19 and C20? You might have fried them...
Also, do you know how your circuit is supposed to sound like? With proper 9v supply..?

[antonis]

Hi & Welcome..

Step 1: Replace C20 & C19..
Step 2: Replace D8..
Step 3: Replace C15 & C17..
Step 4: Open a brand new bottle of malt for libation..



P.S.
Do NOT reverse steps order..!!!

[11-90-an]

Hi & Welcome..

Step 1: Replace C20 & C19..
Step 2: Replace D8..
Step 3: Replace C15 & C17..
Step 4: Open a brand new bottle of malt for libation..

Don't forget step 5. : Chug!  (unless you are a minor, or you dislike alchoholic drinks. What works for you )

I'm not sure but if you say that you plugged in an AC psu... shouldn't that mean that all the other pedals in your pedal board *might* have some problems too?

[duck_arse]

also high, also welcome, also glug glug.

yer posted built pic doesn't match the board linked/found, so, the third diode from the bottom, left hand side, appears kactus, broken glass. won't kill the pedal but might as well be changed for a good one.

I love the sound of broken breaking glass.

[amaurythewarrior]

Hello to everyone, and thanks for the help,
I don't have any spares I'll have to buy some.
The whammy PSU is 9v as well - well, was (RIP)
I know how it's supposed to sound like based on other successful builds by other people, (same kit). But it was my first time plugging mine, so it did not work normally before

Welcome to the forum...

How much does your whammy psu supply? (I.e. how many volts)

Do you have any extras for C6 and C12, C19 and C20? You might have fried them...
Also, do you know how your circuit is supposed to sound like? With proper 9v supply..?

[amaurythewarrior]

Thank you, will do, C8 and d19 and d20 have already been suggested on another forum.

Hi & Welcome..

Step 1: Replace C20 & C19..
Step 2: Replace D8..
Step 3: Replace C15 & C17..
Step 4: Open a brand new bottle of malt for libation..



P.S.
Do NOT reverse steps order..!!!

[amaurythewarrior]

Ah, well I don't really have a pedal board, I have other pedals, but mostly running on batteries.
And I seem to recall using my cry baby with the same adapter (not sure)
I remember having fried part of my cry baby circuit while first plugging it after the true bypass mod (10 years ago, less experienced)
but I think it was a universal adapter that was 12v, and I did not know about the polarity importance...

Hi & Welcome..

Step 1: Replace C20 & C19..
Step 2: Replace D8..
Step 3: Replace C15 & C17..
Step 4: Open a brand new bottle of malt for libation..

Don't forget step 5. : Chug!  (unless you are a minor, or you dislike alchoholic drinks. What works for you )

I'm not sure but if you say that you plugged in an AC psu... shouldn't that mean that all the other pedals in your pedal board *might* have some problems too?

[amaurythewarrior]

Yes, the board in the kit seems to be different than the one on the schematic
And wow, you can see the broken glass on the diode from the picture?
Happened while bending the legs, I figured it seemed to only be superficial, but definitely, if I'm ordering/buying parts, I'll get a replacement

also high, also welcome, also glug glug.

yer posted built pic doesn't match the board linked/found, so, the third diode from the bottom, left hand side, appears kactus, broken glass. won't kill the pedal but might as well be changed for a good one.

I love the sound of broken glass.

[amaurythewarrior]

And I've taken measurements
Here are my readings (taken to the best of my ability, analog multimeter)
IC1
1:2
2:2
3:0+
4:0
5:0.5
6:1
7:1.25
8:4

IC2:
1:2
2:2
3:0+
4:0
5:0+
6:2
7:2
8:4


IC3:
1:2
2:2
3:1.5
4:0
5:0+
6:2
7:2
8:4

T1
E:2.5
C:0
B:4

T2
E:2.5
C:0
B:0

T3
E:3
C:0.5
B:4

C20: 1.5
c19: 2 (a bit less)

Am I doing something wrong or is there a reason I never read +9 on the transistors and ICs?

[amaurythewarrior]

Ah, so, this is embarrassing...
My voltage reading have to be off, because I stupidly took a battery from my active pickups bass, assuming it had enough juice left...
But when I measure it, it reads 4vdc, same as on the ICs...
So I'll try a new battery tomorrow, I wish it could be as simple as that but....

[antonis]

I wish it could be as simple as that but....

But you might re-check for shorted C20 'cause ALL non-inverting inputs should measure +2V..

What puzzles me is voltage measurement inconsistency between IC1 pin 1 & IC3 pin.. There shouldn't be any DC path leak for half a volt drop across 3k3 resistor (R21)..

[amaurythewarrior]

But you might re-check for shorted C20 'cause ALL non-inverting inputs should measure +2V

Forgive my ignorance, but not sure how to do that, measure resistance both ways? Has to be done out of the circuit?

[antonis]

No need for apologizing...
(It was my bad 'cause I tend to consider some things obvious.. )

Cap measurement should be taken out of circuit but in your case you may utilize resistance measurement without powering the circuit..
The only resistor in parallel with C20 is R32 (10k) so you should measure almost(*) this resistance some time after measurement probes implementation..
(descending or ascending according to cap charge and probes polarity..)

(*) there is plenty of other resistors in series/parallel configuration but their values are significantly higher than 10k so they can't affect actual measurement..

P.S.
Of course, you can verify C20 bad working state (shorted..) by simply desoldering it and powering circuit, even with 4V battery..
You should measure 2V at R31/R32 joint..

[amaurythewarrior]

I measure 6k/5.5k at C20 - why am I not surprized

I'm currently out of desoldering braid so I can't removing competely for the time being.

[antonis]

That could be caused by C19 shorted (effectively setting R31 & R32 in parallel) but it should also short power supply..
Is there any chance for your battery to be initially fully charged..?? 

[amaurythewarrior]

Ahah, yes, obviously I'll get a new battery. I'm in France, and it's already late here.
I'll get one tomorrow, if that does not help I'll order replacement parts, which I might have gotten from a shop if I were in a bigger city.
But since I'll have to pay shipping, I'd rather do it once only. And thanks again!

[11-90-an]

I highly recommend getting a rechargable battery.
Saves you much money and effort.
When you're not doing anything: plug it in the socket!
Within a few hours, full charged again!

Now also, please buy a charger for the battery too...

[amaurythewarrior]

I have one, but the charger itself is not at my place. The thing is I don't use pedals often, so rechargeable batteries was the best option. But now that I'm doing DIY, I'm considering having more...