Messages

Thank you Brian! Your build looks perfect, I'm jealous.

Thanks Brian! I hate to put you through extra work, it will probably turn out to be something stupid on my part.

However, if you can update the build doc for the MOW (not DX) with the voltages, that page appears to be cut off on the bottom.

*update*
The signal is clean going into pin7 of 1st 3005, the bias1 trimmer directly adjusts the voltage there.
The sound on pins3,4 (1st 3005) is helicopter noise only and changes speed with bias1 trim

pin2 (1st 3005) is very weak on both 3005 and 3101 - this is where I'm focusing my attention rn.
I think I might have killed the other 3101, I swapped them places to see if that did anything and I had 0v on pin2, swapped back and got 0.3v, at least something...

Q2, Q3 voltages look good
-that's as far as I've gone, signal hitting pin7 of 2nd 3005 is same helicopter as output of 1st 3005

Thanks for any further help!
I am determined to get this pedal working!

Hey Benny, any luck?
I'm in a similar stuck point on my MOW, signal into the first XVIVE3005 pin7 but only clock or silence out pins3,4

I'm getting so used to probing this circuit, I'm kinda gonna miss it when it's fixed!

No worries Brian! I may have been a little rough on some joints that I desoldered while debugging, and the pads just kind of lifted off the board, not something I've experienced with other pcbs (doesn't mean it's not my fault).
However the 2 spots near the NE570 (R18 to pin7, and down to C13) were never stressed, just not connecting for some reason.

I've got signal up to pin7 of the XVive 3005, but alas, it's not coming out pin3, 4 and the voltages are off on the 3005 and 3101... I'm digging in again to look at continuity over every connection in that area...

Is there another voltage divider up near the 3005 that would cause pin2 to be weak and 3, 4 to be super high?
Is it possible the voltage on the 3005 is a matter of the trimpots?
-something I read on another forum:
"As you trim the pin 7 "bias" voltage, pins 3 and 4 should follow, but about 2V lower. They are MOSFET source followers. The exact input/output difference depends on MOSFET threshold voltage, which depends on chip-maker and wafer processing." PRR

Aha! I had a breakthrough.
I realized that R18, R19 are a voltage divider affecting the pin7 of my bane. I tried many things, different values, etc.
Finally discovered the trace in the PCB was bad.

I actually had to jumper 2 different traces on the PCB that are on the layout but were not making continuity.
Either my usual very careful build style was too rough for the PCB or the QC on it was questionable.

I'm moving on to the next step and hopeful again!

thanks Harry
It's already been over a month this thing has been on the desk. I've had some fun in between working on my '68 Bassman and socketing parts in my Klon and MXR Dist+ getting really cool results XD

Also, as I mentioned in another post about this project, I don't think it is possible to fit in the enclosure as designed. I followed the drill pattern exactly and there is just no way that the DC Jack will fit, I had to start over with a bigger box.
Is it possible Brian just moved onto the DLX and there's something amiss with this design?

I posted on this in another category but the only responses I've had were to repeat my due diligence (reflow, check values, etc). If it turns out I did miss something I will kick myself, but honestly, I've got a half dozen working pedals (among my other electronics projects) and this one is just not playing nice.

Has anyone completed a Man O War (not dlx)?

I just can't find anything wrong with my build, it gets to the NE571N and just stops.

The voltage on the output (pin7) is 11.11v when it should be only 2.97v.

also voltages on Q2 are 12v, 10.75v, 10.4v and should be 11.71v, 2.96v, 2.39v (Q3, Q4 are likewise high on B, E pins)

All the other voltages seem within acceptable range, but the signal basically stops at inside the 571 and becomes a helicopter.

I've tried different OPAMPs, Transistors, and another compander, same result.
What else can I do?

Thanks!

What components would be responsible for high voltage on Pin 7 and a tiny blip of good sound followed by tick tick tick tick...

The sound is good through the output (C5), Q1 (good voltages and sound), and ok voltages and sound out of Pins 5, 2, and 3 of the SA571, someone on Facebook suggested it could be a "DC biasing" issue, what components are suspect?

Thanks!

I used the green Bi-Polar caps where ever I had one of the correct value, just playing with the special looking parts in my parts box. Is that ok to do? Do Caps need to be polarized when the schematic calls for it?

Pin7, the output of IC2 (SA571N) is still like double what it should be. How can I diagnose this?

I have found that I do get a blip of good audio on Pin 7 right when I touch the probe to it, then it goes to *click, thrum, click* (and from there throughout the rest of the circuit).

I have checked as many things as many times as I can.
One thing is the PCB has gotten damaged in a few places from desoldering and I've had to make a couple jumpers.
There's a chance there's a bridge somewhere on the top of the PCB I cannot see because it's under components.

What do you mean check the polarity of the np cap?

whelp, nevermind that idea. The Build Docs says the board is CBE so my 2N5088s are correct. (*read the footnotes)

Would my overzealous use of non-polar Caps be the problem?
I ordered a NE570 to replace the SA571

I think I just had an "aha!" moment.

I've used 2N5088's for Q1-Q4,. I think it's pinned for 2SC1815, which is a Common Collector E, C, B pinout. The 5088s are Common Base, E, B, C.

How can I use a 5088 in place of a 2SC1815? Is there a trick to cross the legs or something?

I have a proper Hershey's on each joint, and while this did have an effect on the noises I can get with the audio probe - louder, fuzzier, clicking... Still no good signal past the SA751
There's a fuzzy helicopter kinda sound anywhere past PIN 6 of the SA751

Why is the signal reaching SA751 (PIN 6) and then not coming out PIN7?
(is it a clue that the voltage on this pin is 2x what it should be)?

It's interesting that the build documents say:
"Use an audio probe to probe pin7 of IC3 to verify that you have signal to the input of the first BBD.
If you do not, check pin7 of IC2a and the emitter of Q2 for output. Debug as necessary"

PIN 7 of IC2a (SA751) must be a critical junction, what does it mean that I'm getting right up to it and not out of it?

Thanks for looking at it. I'm a little sloppy sometimes

I see a few joints in the pics that look sus, so I'm reflowing and cleaning up the board a little more (since taking the pics)