Non-working Bassballs

[Baran Ismen]

Morning all,

Last night I finished my 2nd project with great hopes, however all I got was a DI sound mixed with a rather hi-freq hiss, and nothing else. I've followed the below project. Also the dist. switch (which is an on/on, 3-pin switch) totally kills the sound when switched on one side.

http://dirtboxlayouts.blogspot.com/2022/10/electro-harmonix-bassballs-pedalpcb.html

First I noticed that I misplaced the 560pf on K1/L1 into J1/L1, fixed that, and traced all of the pins one by one and all is fine, no cold solder, jumpers & cuts are just fine. There's no short between strips also.

Now I'm trying to debug to see what would be the problem, and I wonder if anyone has done this project (or a similar one with attack,decay,hi & low pots) and would assist me on this. Here's the schematics of this modded version.

https://docs.pedalpcb.com/project/Lowballer-PedalPCB.pdf

[duck_arse]

you still need to follow procedure:
https://www.diystompboxes.com/smfforum/index.php?topic=29816.msg202738#msg202738

and post photos.

[Mark Hammer]

Have you confirmed that the pinouts you are assuming for the two transistors, being used like voltage-controlled resistors, are indeed their actual pinout?  Some are E-B-C, looking at the front flat side, from left to right.  Some are E-C-B.  Some are the one left-to-right pinout, looking at the round side, and some are the other pinout.  This can vary from 2N to BC to 2SA type, and can also vary from one manufacturer to another.  I find whenever transistors are involved, it is always good to start with a datasheet or at least pinout for THAT particular transistor, and confirm it with the hfe test on my meter.

That's obviously not the only way things could go wrong, but it's common enough.  However, the fact that you get NO sound, rather than an unchanging filter sound, suggests the transistors are not the problem.

Another source of dysfunction is maltreatment of switches, by novices applying far too much heat to them when soldering leads.

[Baran Ismen]

Just came for some additions.

I've measured the voltages for both ICs, which are;

IC-1 (1458)

1- 4,52
2- 4,52
3- 4,42
4- 0
5- 0
6- 7,53
7- 8,54
8- 9,05

IC-2 (4558)

1- 4,52
2- 4,52
3- 4,51
4- 0
5- 4,53
6- 4,51
7- 4,5
8- 9,05

I've used 2n5088 transistors (and tried on both ways), not helped. ICs are also the same, and so are the diodes, pots, and everything. The switch is an SPDT on-on (weird thing with it that on one side, it completely cuts the sound off, but the contacts are just fine and beeping my voltmeter between 1-2 and 2-3 when measured over the board)

I exactly copied the layout as it is, I've triple-checked cuts, jumpers, pot connections, the parts and their holes, and whether there's a cold solder or peeled-up copper; everything is intact.

All I hear when powered, is a fixed and notched hissing, like a manually set filter, but it's blended by the DI sound. Playing with the Low pot changes this frequency just a bit, and applies just a bit of a high-filter so to speak.

I'm in contact with Christopher Stelloh -the creator of this layout- via Instagram, he says he made this layout before twice and it worked as it should.

If I need to check anything else, please let me know and I can add.

[antonis]

Could you take measurements on all BJTs legs..??

[Baran Ismen]

Could you take measurements on all BJTs legs..??

Sure can. Should i measure the transistors only, or the sockets? Also shall i measure them when mounted or not?

[Baran Ismen]

Could you take measurements on all BJTs legs..??

On all 3,i measure around 105k resistance between base and collector & emitter legs, e and c legs are not showing any value. I removed them and measured outside of the board.

Note that i read these on ohm Mode, on diode/sound Mode of the multimeter, i dont read any values from any legs of all 3.

[antonis]

No, I ment voltage measurements on board..

Black probe on GND and Red probe on C-B-E respective points..

[Rob Strand]

Could you take measurements on all BJTs legs..??

On all 3,i measure around 105k resistance between base and collector & emitter legs, e and c legs are not showing any value. I removed them and measured outside of the board.

Note that i read these on ohm Mode, on diode/sound Mode of the multimeter, i dont read any values from any legs of all 3.

See if you can use the multimeter diode checker on base to collector and base to emitter.  You need to get the meter polarity correct but once you do that the same meter lead will go to the base for both measurements.

I doubt you will measure the transistor resistance using a multimeter with the device running.

(You could try just replacing the transistor.   If you don't have a 2n5088 try whatever NPN you have like a 2N3904.)

[Baran Ismen]

Could you take measurements on all BJTs legs..??

On all 3,i measure around 105k resistance between base and collector & emitter legs, e and c legs are not showing any value. I removed them and measured outside of the board.

Note that i read these on ohm Mode, on diode/sound Mode of the multimeter, i dont read any values from any legs of all 3.

See if you can use the multimeter diode checker on base to collector and base to emitter.  You need to get the meter polarity correct but once you do that the same meter lead will go to the base for both measurements.

I doubt you will measure the transistor resistance using a multimeter with the device running.

(You could try just replacing the transistor.   If you don't have a 2n5088 try whatever NPN you have like a 2N3904.)

When I took these measurements, device wasn't running, I actually removed them from their sockets and measured externally I got 4 more 2n5088 on the toolbox. Luckily one of the mounted ones had one of its leg broken and it stuck inside the socket  it'll take some time to replace it.

No, I ment voltage measurements on board..

Black probe on GND and Red probe on C-B-E respective points..

I'll do that, too and write the results.

[Baran Ismen]

Could you take measurements on all BJTs legs..??

On all 3,i measure around 105k resistance between base and collector & emitter legs, e and c legs are not showing any value. I removed them and measured outside of the board.

Note that i read these on ohm Mode, on diode/sound Mode of the multimeter, i dont read any values from any legs of all 3.

See if you can use the multimeter diode checker on base to collector and base to emitter.  You need to get the meter polarity correct but once you do that the same meter lead will go to the base for both measurements.

I doubt you will measure the transistor resistance using a multimeter with the device running.

(You could try just replacing the transistor.   If you don't have a 2n5088 try whatever NPN you have like a 2N3904.)

I actually tried measuring on Diode mode as mentioned, yet I got no readings. But transistors are operational seemingly as removing one of them even cuts the output sound completely.

[duck_arse]

I exactly copied the layout as it is, I've triple-checked cuts, jumpers, pot connections, the parts and their holes, and whether there's a cold solder or peeled-up copper; everything is intact.

if you were to show us some photos, we might be able to suggest a reason for the bad voltages on IC1. we might see, for instance a missed cut between pins 4 and 5 of that IC.

IC-1 (1458)

1- 4,52
2- 4,52
3- 4,42
4- 0
5- 0
6- 7,53
7- 8,54
8- 9,05

[Baran Ismen]

I exactly copied the layout as it is, I've triple-checked cuts, jumpers, pot connections, the parts and their holes, and whether there's a cold solder or peeled-up copper; everything is intact.

if you were to show us some photos, we might be able to suggest a reason for the bad voltages on IC1. we might see, for instance a missed cut between pins 4 and 5 of that IC.

IC-1 (1458)

1- 4,52
2- 4,52
3- 4,42
4- 0
5- 0
6- 7,53
7- 8,54
8- 9,05

Hope these ones would help.

https://ibb.co/dMWJ3b0
https://ibb.co/S7ZR3Jm
https://ibb.co/jW099VD

[antonis]

No reason for cut between pins 4 & 5, Stephen..
(both are grounded, according to schematic..)

[Baran Ismen]

No reason for cut between pins 4 & 5, Stephen..
(both are grounded, according to schematic..)

Is it normal or not, i didnt understand 

I suspect on the 470nf polarized cap being connected to wrong Row. I checked the mad beans slurpee pcb today and made a tracing, and i found that on that pcb, leg6 of the ic1 is connected to 470nf whereas on this layout its not. Here i marked while tracing.

https://ibb.co/4ts477N

[duck_arse]

who, really, who, laysout a board like this? note the cut between IC1's pin 4 and 5, and then follow their connections. who?

what voltages are we expecting on pins 6 and 7 with 5 to ground?

[duck_arse]

I suspect on the 470nf polarized cap being connected to wrong Row. I checked the mad beans slurpee pcb today and made a tracing, and i found that on that pcb, leg6 of the ic1 is connected to 470nf whereas on this layout its not. Here i marked while tracing.

excellent work. connect that cap so it's on rows F and E and you should be right. you will need to alert the layouter to the error.

[Baran Ismen]

who, really, who, laysout a board like this? note the cut between IC1's pin 4 and 5, and then follow their connections. who?

what voltages are we expecting on pins 6 and 7 with 5 to ground?

Well, names there, he has some other projects as well, and hes been helpful up to a degree on instagram, but he doesnt know about the should-be voltages of the pins.

I suspect on the 470nf polarized cap being connected to wrong Row. I checked the mad beans slurpee pcb today and made a tracing, and i found that on that pcb, leg6 of the ic1 is connected to 470nf whereas on this layout its not. Here i marked while tracing.

excellent work. connect that cap so it's on rows F and E and you should be right. you will need to alert the layouter to the error.

Is this the only fault you detect?

[duck_arse]

you detected it.

[Baran Ismen]

you detected it.

I mean if you found anything else apart from this