First project not working. Please help !

[jfrabat]

high school typing class (we learned on these massive IBM Selectric typewriters, although there were a few more "modern" typewriters in the classroom that were not deafeningly loud and had built-in correction tape).

We had 1940s(?) manual typewriters.  No, I'm not that old, this was in the 80s.  Somehow I passed that class, still can't type worth a damn, slow and gotta look at the keyboard.

Same here...  Old a$$ Olympia branded typewriters; hit the key wrong, and your finger would get caught between the keys!

EBK, so did you take a picture of your "typo"  HAHAHAHAHA!

I'm away for a few days so I'll have to put into practice what I've learned here next week.

Let us know how that goes.  As for where to ground, I usually just use an alligator clip to one of the jack's sleeve (choose either one) and probe with the red without having to worry about correct grounding.  If your issue is a bad ground, all your readings will be out of whack, and you will check your ground.

[sunday_luthier]

Okay,

So I soldered the IC1 socket, inserted the new TL072 chip, and cleaned up the iffy solders.

The problem is still the same. 

The multimeter gives a reading of 33 ohms for the R11 resistor.  So it seems right.

I removed the IC2 chip, measured the voltage again at the R11.  It was now 8.91 (instead of the initial 7.37).

Could the issue be a faulty IC2 chip?

Cheers,

[11-90-an]

Now that you did another solder job,

May i request for pictures again? Front and back...

Also, IC1 pin voltages, please...

[sunday_luthier]

The IC2 chip is in poor condition (see pics).  I removed it and I am now considering either throwing the whole project away or ordering a new IC2 chip and giving it one last go.  This is very frustrating.

IC1 voltages (without IC2 installed) are :

1 - 4.46
2 - 4.46
3 - 4.46
4 - 0.00
5 - 4.46
6 - 4.46
7 - 4.46
8 - 8.93

[ElectricDruid]

IC1 voltages look good now.

Why did you take IC2 out? You can't debug something if you keep making changes to it. It's like trying to hit a moving target!!

Ok, the insulation on some of the wires you've attached is a bit melted, and you caught the potting box with the soldering a bit, but it's just a bit battle-scarred. Nothing that should stop it working. Someone else mentioned earlier on that it looks from the PCB like the intention is that you were supposed to just poke the pins of the Belton module through the board and solder those those directly, rather than having to strip and solder ten fiddly little wires. Once it's soldered, you'd just fold it down against the back of the board (it's all sealed up so it can short anything).
But you've done it that way now, so it's probably better to stick with it.

[sunday_luthier]

The problem with the Belton module is that I broke the prongs when lifted it to desolder the IC1 chip.  The prongs broke almost flush with the module so it was nearly impossible to solder each little wire to these tiny "stumps".

And yes, the iron hit the module several times so my guess by now is that with all this tampering I may have screwed up the IC2 module. 

[ElectricDruid]

Ah, ok. I see. Trying to lift it up again to get underneath would definitely be difficult. And yes, soldering little wires to the stumps is also going to be tricky.

So all in all, I think you've done pretty well! You managed to get wires onto all the pins, and get those wires into the board. Good work - fiddly and frustrating work, I imagine, but you managed it, so well done. I wouldn't assume that the module is dead at all. Perhaps a little battle-scarred, but dead? No, still fighting is my guess.

The thing is... it's hard to know whether it's working unless it's in the circuit, so I still don't understand why you took it out.

[11-90-an]

Try sticking it there and see what happens...

[Steben]

Welcome my friend. Reverb as first kit.... bold move. I must admit it is kind of comforting to see such a kit did not work at first. This board would be full of shattered pride. Hang on and youll succeed.

[jfrabat]

Sunday, do not get discouraged.  This whole DIY Pedal is a process of incremental fixes until the pedal does what it should.  We have all been there (in fact, I changed my signature to say something about this because this is more the norm than the exception, at least for me!).

I agree with Druid that I do not think the Beltron is shot.  I would put it back in and troubleshoot it.  But that's me.  If you want to wait for the new one, that is fine as well.

[sunday_luthier]

Will do!  Thanks for the encouraging words 

[sunday_luthier]

I guess it was so obvious I didn't see it.  Upon closer inspection after removing the IC2 chip, I noticed this little guy :


No solder at all!  Fixed it and soldered the IC2 chip back on.

Put the whole thing in the enclosure, plugged my guitar and played with it about a half hour.  I'm keeping my fingers crossed but I think it's all good now. 

IC1 reading

1.  3.68
2. 3.68
3.  3.68
4.  0.00
5.   3.68
6.  3.68
7.  3.68
8.  7.39

Thank you for all the help !

[11-90-an]

If it works, it works...

happy to see you fix the problem. congratulations!

[jfrabat]

Glad you got your fixed!  I am making 2 EQs (IDENTICAL BOARDS!) and I got one working, and the other doing all kinds of wonky stuff.  Go figure!  Most of the time it is something basic, like in your case, but I really wish I could find it already!  LOL!

[willienillie]

IC1 reading

1.  3.68
2. 3.68
3.  3.68
4.  0.00
5.   3.68
6.  3.68
7.  3.68
8.  7.39

Sounds like you're using a battery, and it's draining fairly quickly.  This is one of those circuits that you'll really want to use a wall wart for, a battery eater.

Good to hear you got it running!

[sunday_luthier]

No, I'm using a wall wart.  The 7.39 V reading has been questioned from the start.  I have no idea....  But it's working  !
If it breaks down, I guess I'll investigate this issue further.

[antonis]

No, I'm using a wall wart.  The 7.39 V reading has been questioned from the start.  I have no idea....

Measure your wall wart output, subtract 7.39 and divide the result with 33.. You'll get circuit current consumption and judge if it's OK or not.. 

[duck_arse]

I seem to recall we diagnosed this same volts drop problem on a build some while ago, deciding that taking the regulator input voltage after the supply filter was a bad idea due to the high[er] current draw of the Belton thing. would be simple to have "fixed" it at the design stage, or the board layout stage, but probably not a mod for beginners to attempt.

unless they were really game.

[sunday_luthier]

Well it's been working about 2 weeks now.  Brought it to band practice and got some nice comments!  It sounds great. 

Here's a pic with the enclosure (yellow paint +decal+clear finish).

I am very happy with the result and glad I didn't toss it out  .  thanks for all the help !