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Projects => Tech Help - Projects Page => Topic started by: Comfort Player on March 20, 2012, 04:58:53 PM

Title: Pork Barrel - Good dry, but no chorus
Post by: Comfort Player on March 20, 2012, 04:58:53 PM
Buillt my Poker without any substitutions. I used the 3201 / 3207 chips.

I get a good bypass and when I engage the 3pdt I get the same a clean guitar signal.  No chorus effect.  My LFO is flashing.

Taking voltages on the ICS they look pretty much in line with other posts in the section except for the 3207.  My readings are:

1-0
2-3.72
3-4.04
4-7.45
5-0
6-3.63
7-0
8-0

I'm pretty sure pins 5 - 7 are not correct  :) but not sure where to look from here.  

I have reflowed the socket and the jumpers and parts around IC4 but I am not really sure where to look ?
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: DutchMF on March 20, 2012, 05:07:38 PM
I'm absolutely not an expert, but did you use the bias trimmer? My build had no chorus at all when fired up the first time, but as soon as I started twisting that trimpot....... WoW!! Just my 2 cents, you might want to wait for the experts.......

Paul
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: Comfort Player on March 20, 2012, 05:12:49 PM
Thanks for the tip, but I tried the trimmer.  No change to the signal.  Sounds the same as my clean signal.
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: Scruffie on March 20, 2012, 05:15:07 PM
2 & 6 seems fine, clock is going...

3 is okay, it has bias voltage.

5 should be voltage (8Vish) have you messed up the zener somehow?

7 & 8 should also have an output voltage... but fix pin 5 first.
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: Comfort Player on March 20, 2012, 05:26:38 PM
Quote from: Scruffie on March 20, 2012, 05:15:07 PM
2 & 6 seems fine, clock is going...

3 is okay, it has bias voltage.

5 should be voltage (8Vish) have you messed up the zener somehow?

7 & 8 should also have an output voltage... but fix pin 5 first.


I checked the zener and it is oriented the correct way. I get 8.10 volts on the side with the strip and 0.00 on the other pin.  I reflowed it and rechecked voltages on the IC and there was no change
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: jkokura on March 20, 2012, 05:45:48 PM
I'd bet you have either a minute break in the trace or perhaps a leak to ground somewhere in there. Have you got some good pictures for us to look at for you?

Jacob
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: Comfort Player on March 20, 2012, 06:00:19 PM
Quote from: jkokura on March 20, 2012, 05:45:48 PM
I'd bet you have either a minute break in the trace or perhaps a leak to ground somewhere in there. Have you got some good pictures for us to look at for you?

Jacob

I can take some..Give me a few.  If I understand correctly, I should have current coming in in pin 5.  Where would that be coming from ? In otherwords what is the next component upstream ?  Looking at the schematic ( I am terrible at schematics ) it says out 1.1 ???? Not sure what that is ?
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: jkokura on March 20, 2012, 06:12:30 PM
It would help me to know which Pork Barrel you're working with. Is it the latest one? A Manufactured PCB? A home etched one? Until then, I can't say for sure. Not to mention that Scruffie is probably the better one to answer. He's sort of our resident BBD expert round these parts.

Jacob
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: Scruffie on March 20, 2012, 06:14:57 PM
Quote from: Comfort Player on March 20, 2012, 06:00:19 PM
Quote from: jkokura on March 20, 2012, 05:45:48 PM
I'd bet you have either a minute break in the trace or perhaps a leak to ground somewhere in there. Have you got some good pictures for us to look at for you?

Jacob

I can take some..Give me a few.  If I understand correctly, I should have current coming in in pin 5.  Where would that be coming from ? In otherwords what is the next component upstream ?  Looking at the schematic ( I am terrible at schematics ) it says out 1.1 ???? Not sure what that is ?
I think that's a Typo, it should go to VD, so you are looking at C24, D4 & R40

You did install the jumpers on the PCB correctly yeah by the way?

Quote from: jkokura on March 20, 2012, 06:12:30 PM
It would help me to know which Pork Barrel you're working with. Is it the latest one? A Manufactured PCB? A home etched one? Until then, I can't say for sure. Not to mention that Scruffie is probably the better one to answer. He's sort of our resident BBD expert round these parts.

Jacob
Only the latest has the 8V2 Zener and 3207 option.
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: jkokura on March 20, 2012, 06:16:58 PM
See... told you Scruffie knows best.

Jacob
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: Scruffie on March 20, 2012, 06:19:25 PM
Quote from: jkokura on March 20, 2012, 06:16:58 PM
See... told you Scruffie knows best.

Jacob
Haha, missed that part of your post, why thank you  ;D
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: Comfort Player on March 20, 2012, 06:23:55 PM
Sorry about that. The latest board bought from MB.

I see the VD section you are referring to.  I was looking at pin 5 on IC4 and trying to trace backwards from there and it is labelled Out1.1.

Pictures on the way as soon as I can get photobucket to respond  :'(
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: Comfort Player on March 20, 2012, 06:32:54 PM
Pics.. Board starting to get a uglier from the reflow's

(http://img.photobucket.com/albums/v685/LookingforLarri/Chorus%20Pig/Chorus011.jpg)
(http://img.photobucket.com/albums/v685/LookingforLarri/Chorus%20Pig/Chorus011.jpg)
(http://img.photobucket.com/albums/v685/LookingforLarri/Chorus%20Pig/Chorus013.jpg)
(http://img.photobucket.com/albums/v685/LookingforLarri/Chorus%20Pig/Chorus014.jpg)

Let me know if these are not good enough
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: Scruffie on March 20, 2012, 06:40:40 PM
Quite a few bad looking joints there... you should reflow.

What voltages do you get on the 3207 without it in the socket?
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: Comfort Player on March 20, 2012, 06:53:06 PM
No chip in socket

1-0
2-3.68
3-4.05
4-7.45
5-0
6-3.6
7-0
8-0

when I put the chip in the only difference is

5=(-0.01)
7=0.02
8=0.02

Reflowing now, afraid I am going make it worse...

Should the jumpers under the IC have voltage ?
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: Comfort Player on March 20, 2012, 07:20:37 PM
Fixed IT!!!! 

Was not a reflow problem.  When I put in the jumper for the IC I thought I had created a solder bridge between pin 5 and the jumper so I cleaned it up and scaped away excess solder between the two points.

While trouble shooting I noticed that the jumper had voltage and that pin 5 did not and wondered if I had broken a trace between the two while cleaning my solder bridge. 

So I created a connection between pin 5 and the jumper an TA DA !!!  Voltage on pins 5, 7 and 8.

Hooked it up an it works as expected.   Thanks to Scruffie and everyone for the help.
 
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: DutchMF on March 20, 2012, 07:21:51 PM
Good to know you got it fixed, enjoy!!
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: Comfort Player on March 20, 2012, 08:07:06 PM
Thank Dutch.  Very nice souding chorus, lush and rich. Well worth the effort and lesson learned during the build.
Title: Re: Pork Barrel - Good dry, but no chorus
Post by: bigb1984yaherd on March 21, 2012, 02:36:41 AM
I have zero help for you since I am going through my own issues with the pork barrel right now aswell but with the Tl062. All I can say is I feel your pain, I reflowed and replaced IC and transistors all evening. Still no luck, I hope you fair better.