Debugging Janglebox

[mdtcarroll]

Hi There,
Trying to debug the Janglebox (http://tagboardeffects.blogspot.com.au/2014/06/janglebox.html) and wondering whether anyone can offer advice please? Hoping another set of eyes might reveal a forehead slap for me :-)

I've re-run solder over most of the joints again

Bypassed signal is ok. I'm getting signal to pins 2 & 3, but nothing from pin 6. Also, I get signal at Switch 1 but not switch 3. I'm using CA3080E, which I swapped out for another of the same - so it seems ok.

Voltages are:

P1 0
P2 2.89
P3 2.89
P4 0
P5 0.64
P6 0.62
P7 9.35
P8 0

Q1 E 1.86, B 2.24, C 9.35
Q2 E 0.11, B 0.62, C 9.22
Q3 E 0, B 0 C 8.4
Q4 E 0, B 0, C 8.4
Q5 E 8.67, B 5.5, C 9.35

Attaching image of layout first. Hopefully it's something there that I just can't see. I used a 91k instead of a 92k at Gain 3

Many thanks for any who take the time to help. I'm certainly loving the learning experience.



Regards,
Mark

[Ciaran Haslett]

Hi and welcome Mark (another Mark!!!!!)

Your 10n box cap bottom right...is it in the right holes?  Looks like the bottom leg is where a cut should be?  Hard to tell without a pic of the solder side.

[Beaker]

Hi Mark,

Ciaran is right, nice big photo of the top, but we need a photo of the solder side to be sure.

Thanks,
Mark. (one of the many!)

[mdtcarroll]

Wow. Thanks for replying so quickly! Really appreciated.

Yeah, the 10n is ok. it's size does make it difficult to tell.

Attaching underside pic - where blue wire at bottom left is Gain 3 - nearest to the 10n

[mdtcarroll]

Adding another pic after adjusting shadows to make it a bit clearer to see... :-)

[mdtcarroll]

Aha! I just found that I missed a cut near D2. Will test again tonight and see how that goes.
I thought I'd show you all the cuts and links to help - but it helped me more :-)

[mdtcarroll]

Looking at that cut, I figure that all the signal would have been sent to ground via the 470p

[Ciaran Haslett]

Good catch Mark.  Sometimes it just takes a fresh perspective to see the obvious.  Happens to us all more times than we care to admit.

All the best

[mdtcarroll]

Thanks Ciaran! Really appreciate the support. I feel like I've just found some new friends :-)

Well I just tested again this morning, briefly. It seems like putting that cut in has not changed my results - weirdly enough. Still getting signal to pins 2 & 3, but nothing from pin 6. I'll have another closer look tonight to confirm and see if there are any other differences.

Thanks again!

Mark

[mdtcarroll]

I checked the voltages and they all look pretty much the same.

P1 0.44
P2 2.89
P3 2.89
P4 0
P5 0.64
P6 0.62
P7 9.35
P8 0

Q1 E 1.86, B 2.24, C 9.35
Q2 E 0.11, B 0.62, C 9.22
Q3 E 0, B 0 C 8.4
Q4 E 0, B 0, C 8.4
Q5 E 8.67, B 5.5, C 9.35

[mdtcarroll]

Pulled each of the transistors and checked the hfe, just to ensure they they weren't damaged from the cut not being there - but all ok. They average an hfe of 480-490

[mdtcarroll]

OK, new discovery.

I'd previously made a Keeley 4 knob compressor, so I thought I'd try the CA3080 IC in that - to see whether it still worked. Alas, NO! So I tried the LM3080 from the Keeley in the Janglebox and hey presto it worked!

No amount of troubleshooting the circuit is going to get past a bad IC - actually 2x bad IC's :-)

So, it looks like I've got to the bottom of it.

So, thanks again for helping me help myself :-)

Really appreciate all your help!

Regards,
Mark

[mdtcarroll]

And the good news is that I found that I had a spare LM3080 which must have been when I made the Keeley Comp. Happy days!

[Ciaran Haslett]

Glad to hear you got it sorted Mark!  

Unfortunately you've just experienced an issue that becomes more common every day.  I started this hobby 4 odd years ago and even then it was already a problem......fake/out of spec through hole components!  As you said....no amount of debugging the peripherals will help if the IC is knackered!

I built a Janglebox compressor (based on the Ross, Dyna comp...just like the Keeley) a long time ago.  I didn't have any 3080's and was already turned off ordering ones in fear of getting a dud.  So using a conversion board Mark (lvlark) drew up....I bought a ton of LM13700's.  These are relatively new devices, still available by the train load, and cheap as hell.  They're pretty much 2 3080's in one.  My compressor worked out great with this IC...and I even went on to build a bunch of filters with them.  Never had a problem.  You can find the pinout conversion here...about halfway down the thread.

http://guitar-fx-layouts.42897.x6.nabble.com/rustbucket-2015madbean-td26020.html#a26171

I would highly recommend buying a few of these.  They're great!

Anyway...enjoy your new compressor (try upping the pot values for some pretty extreme squish lol) and hope to see you around more often

Ciaran

[strassercaster]

glad you figured it out. i spent hours trouble shooting my small stone tonepad build it was like my 15th build for the life of me i couldnt find any mistakes. i forgot i ordered 10 ca3080 from aliexpress. to my delight they showed up and i popped them in and it worked and the dyna comp i had just built and spend several hours troubleshooting also worked. i built the dyna comp to test the chip once i had two circuits that didnt work i was starting to wonder. ill bet i wasted at least. 6 hours between the two builds all some so chines counterfitter could make 6 bucks man that ticks me off.i highly reccomend  polida2008 on ebay i have had good liuck with them. .so how do you like it?

how does it compare with the keeley dyna ross tyoe compressors?

[Beaker]

Strassercaster, Polida on ebay are avoided by many on here due to fakes... just sayin'.

The Janglebox is just a modified Ross/Dynacomp, so don't expect too much difference to what you already have.

It is in my opinion though, the best compressor ever! I just love mine.

[jghfslk]

Does anyone know of a reliable source for the CA3080 or a similar chip?  I'm having issues with my build and am thinking my chip is the culprit.

[Travis]

I built this twice to no avail as well, although I just about always suspect builder error before faulty part. I finally rebuilt it with an LM13700 and that finally worked. Looks like 3rd time was the charm with this one for me. Not sure if my IC was faulty or if I made a mistake, but I can't find a mistake for the life of me and don't want to debug anymore now that I have a working board

[jghfslk]

The reason I'm thinking it might be the chip is because when I probe it my signal becomes very distorted at pin 6 (and will eventually crackle and cut out).  I've tried replacing the chip and the same thing happens.  When I have had the brief signal at pin 6, I get signal at the output.  Could I have a power issue with the chip?  The 9v signal goes directly to pin 7 so I would think I wouldn't have an issue getting it power, but I've compared my voltages to a working build and they seem off (way to high at pin 6).  Any ideas?

[hobbyseason]

I'm having the exact same issue, signal at pins 2+3 and very distorted at pin 6. Did you have any luck working it out?

Maybe I got a bad batch of ca3080s