Celeste Chorus Tech Help Needed

[mistermikev]

using LT1054 charge pump, 2n5088, 2n5457, MC78L15ACP, LM1458N, V3207, CD4047BE
didn't really sub anything other than bbd and using two resisters in series to get r5/r4.

not a lot of opportunity for flux connecting two pads together other than a handful of pads that are really tight

I've checked orientation of electro caps.  at the reg I get expected 15v~

I do get clean signal with the chorus knob the right way and flange/vibe switch set right.
I've traced my signal to pin 3 on the BBD.  I checked the jumpers for MN3207 - looks right to me!
checking pins 7 and 8 of the bbd i get some kind of static.  I've swapped out for another mn3207 and same result. 

Q: looking at other posted voltages... it says pin 1 of bbd should be around 15v?  but this is the ground pin... am I missing something?  I see ~0v on mine.
looking at r36 I get correct voltage... depending on the bias setting I get 7v~ and 7v~ at the trim.

I could really use a pic of the tracks... I can read the schem and spot check... but it'd be real helpful in case anyone would be so inclined as to have mercy on my pitiful soul.

VOLTAGES:
1) 4558
7.44
7.45
7.31
0
7.21
7.44
7.44
14.8

2) MN3207
.3
7.45
4.68
13.97
14.97
7.46
10.08
10.08

4) LM1458
6~
7.47
0
0
6~
7.45
4.7~
14.93

5) 1044

6) 78L15

7) CD4047
2~
13.08
6.3
14.98
14.98
14.98
0~
0
0
7.45
7.46
1.5
2
14.96

2N5457

[BrianS]

Do you have the jumpers oriented correctly for the 3207? I made mine with a mn3007 and it worked first time.  I was going to go the 3207 route but was able to get a 3007.  Someone is going to ask you to post a picture (top and bottom) so go ahead and take one and post it.

[mistermikev]

first off: thank you for your response.

the jumpers are between pins 2/7 and 3/6 if that makes sense.  across the chip.  hard to get a pic of that... but yeah.  I have some 3007 lying round but they are chinese and i figured I would go with a verified smallbear 3207 first... easy enough to swap out after it works and see if these are any good.  I do have some real 3007 in a few pedals but I don't want to put those in an unverified build. 

will shoot a pic of the under side next...

[BrianS]

One of the guys from LectricFX will pop on here soon.  They respond quickly from what I've seen.  I will run voltage on mine in the morning if someone else hasn't. 

[Scruffie]

You're running a 3207 at 15V... it's dead, you missed the part about using a 9V regulator for the 3207 which has a terminal voltage of 11V.

[mistermikev]

thank you for your responses gentlemen.  I very much appreciate it. 

here's how much of a dumb-ass I am: believe it or not I was aware that the mn3207 was lower voltage... but foolishly thought that somehow the jumpers were connecting to a 9v tap... not sure how I thought that was being accomplished... and pretty stupid that it wasn't a sign for me when I took voltage readings from it.  that said, isn't the pinout for 3207 and 3007 the same... so what do the jumpers do?

In the spirit of finding out where I went wrong and perhaps helping others, I have reread the build instructions: I still don't see any note about a dif regulator... am I blind? In retrospect I suppose it is pretty obvious, and I know that it is ultimately on me... but can someone rub my nose in it?

switched to a 9v reg... and believe it or not it did not fry my 3207.  works like a charm.  I can't thank you guys enough.  this thing sounds great.  has a unique quality I can't put my finger on.  not quite a ce2, not quite a small clone although I suppose there are settings where you will be right 'there'. 

cheers,

[Scruffie]

Surprising it's still alive, I wonder if it's suffered any other ill effects though.

On the parts list there is an * by the 78L15 and accompanying note below, perhaps not quite as obvious as it should be, i'll give Keefe a shout.

The 3207 vs 3007 power difference thing with the jumpers, the 3007 expects a negative voltage so we just feed the ground pin with a positive voltage and the power pin with ground and the chip doesn't know any different where as for the 3207 it expects a positive voltage so to switch between the two power and ground pins are flipped.

[mistermikev]

hello,
thanks for the reply scruffie.  I appreciate the education on mn3207 requiring neg voltage.  reading comprehension is obviously not my strong suit. 

not trying to raise a fuss... but honestly, I still don't see the note regarding 9v reg.  I'm going here: http://lectric-fx.com/product/celeste-chorus/ and clicking on the v1.2 pdf.  my parts list has two notes (asterisks)... one regarding extra cap for charge pump and one regarding high output pickup mod. 

at this point, I really hope someone else can confirm it missing because otherwise, out of honor, I'm going to have to punch myself in the face.  If it IS missing, I'd like to think my trials and tribulations can help someone so... there's that.

Either way, I'm in good shape and happy.  The 3207 sounds fine.  fairly quiet unboxed, works through the range of controls and sounds clean thru my battery amp. 
I generally don't keep things powered for more than 30 sec when things aren't going as expected so... perhaps that saved it.  Either way I am going to tempt fate and switch it out for a mn3007 for the extra headroom shortly. 

for the most part, this build went very smooth.  great pcb... hard to get it wrong - but I'm experienced at finding a way in that regard!

cheers,
mike

[WormBoy]

I cannot find a note about using 9v either, so it's not (onl ::)y) you. However, I am notoriously bad at reading those details 

[BrianS]

Scruffie the note fell off the 1.2 doc but is on the version one build doc.

[mistermikev]

whew... I'm not completely daft.

thanks for the response wormboy and thanks for the followup brians.  I very much appreciate the preservation of my sanity.

I have switched the jumpers and 8 of 8 chinese mn3007 will not work in this build - yes I swept the bias trim on all.  4 of 4 others... one of which I'm certain is real, worked like a charm.  replaced the voltage reg with 15v... working great. 

I have contacted my ebay seller... his answer; good or bad, along with his ebay name will follow. 

I'd like to snag some more mn3007 for a madbean and electricfx flanger build... so if anyone can recommend a seller I'd appreciate.  I am aware of smallbear, and will go that route if need be, but I'd like to roll the dice again despite my experience.

thanks again for all the help guys!  You rock.

[Scruffie]

You're quite right, it is missing off the latest build document, I can only apologise.

Anyway, I'm glad you got it working in the end! Hope you enjoy it.

Regarding 3007, i'd strongly suggest going with a reputable supplier, I don't know of any consistent ebay suppliers.

[BrianS]

Smallbear is about the only place that I know of that you can get one and know that it will work. 

[mistermikev]

scruffie - no worries, I learned plenty in the process. 

Scruffie/brians - as I suspected... really hard to find a source for these that isn't $10+ each... guess I'll have to go with smallbear as I know everything I get from steve is golden. 

the ebay user that you def can't get good ones from is 'good-module' - for what it's worth.  No response and I don't expect one.  Learned something there too.

thanks again for your help and putting out fun projects!