Author Topic: Pork Barrel 2019 Help Request [SOLVED]  (Read 288 times)

Cybercow

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Pork Barrel 2019 Help Request [SOLVED]
« on: August 01, 2020, 09:23:41 AM »
Just finished wiring up a Pork Barrel 2019 and have an issue I was hoping some kind soul may have encountered and can pass along a solution. Bypass works just fine. When engaged, I have to swing the "Blend" control all the way over to get any sound. The "Rate" LED pulses and changes speed with a change in the 'Rate' control - suggesting the LFO section is working as it should. I'm using the V3102 & V3207 clock and BBD combination.

As I adjust the trimmer towards one extreme, I can begin to hear some distorted sound and modulation, but no chorus effect.

All the voltages  - EXCEPT on the V3207 BBD are correct. Here are the voltages on the V3207 BBD:
1) 0.002 (effectively zero - supposed to be Vcc [9v])
2) 4.2 (seems to be correct)
3) 3.4 (supposed to be ~4.8)
4) 8.1 (supposed to be ~0.61)
5) 8.8 (supposed to be ~0)
6) 0.008(effectively zero)
7) 4.65 (seems to be correct)
8) 4.65 (seems to be correct)

I suspect a bad BBD, but would like to hear of any other insights or obvious blunders on my part.

I have NOT installed D5 (as per the build docs) and am using the vertical jumper configuration for the clock/BBD combo (also as per the build doc). All socketed devices are securely seated. All components acquired from SmallBear and\or Mouser.



Thank you for your time and consideration.
« Last Edit: August 11, 2020, 07:12:17 PM by Cybercow »
Cybercow - aka: Mark Davis

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Scruffie

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Re: Pork Barrel 2019 Help Request
« Reply #1 on: August 01, 2020, 09:43:20 AM »
1 & 5 are fine (power is switched for the MN3207 vs. MN3007) pin 6 should be the same as pin 2, there's a problem with your 3102.
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Govmnt_Lacky

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Re: Pork Barrel 2019 Help Request
« Reply #2 on: August 01, 2020, 02:58:35 PM »
As Scruffie said, Pin 6 of the 3207 is tied directly to Pin 2 of the 3102. If Pin 2 of the 3102 is good (as you mentioned in your post) then you need to find out what is causing that voltage to drop at the 3207.

Cybercow

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Re: Pork Barrel 2019 Help Request [SOLVED]
« Reply #3 on: August 11, 2020, 07:11:55 PM »
1 & 5 are fine (power is switched for the MN3207 vs. MN3007) pin 6 should be the same as pin 2, there's a problem with your 3102.

As Scruffie said, Pin 6 of the 3207 is tied directly to Pin 2 of the 3102. If Pin 2 of the 3102 is good (as you mentioned in your post) then you need to find out what is causing that voltage to drop at the 3207.

Thanks guys. I didn't have another V3102 handy, so I swapped out both the clock chip and the BBD for an MN3102 & MN3207 and the chorus came to life. A little trimpot tweak and it sparkled just like a great chorus pedal ought.

I then got curious and swapped out the working MN3102 & MN3207 for the original V3102 & V3207 and it worked just as well with the 'MN' chips. (After another quick tweak of the trimpot.) The best guess I can make of what the original "problem" was, is that the clock IC was not seated well enough and . I poked and prodded around with a plastic chopstick and could not get any faults or intermittents.

Played thru it for a good hour (with original 'V' chips) whilst fiddling with the controls & bypassing \ re-engaging several times and it seems solid now. Electronics truly is a fickle mistress.

On further consideration, (while I've not yet tried it), I'm guessing the CoolAudio V3102 & V3207 are interchangeable with their counterpart MN3102 & MN3207 versions. (?) Based on their respective datasheets, it looks like one chip can be the CoolAudio 'V' and the other chip can be the 'MN' version. Conversely, the MN3101 & MN3007 are NOT equally compatible with the MN3102 & MN3207 or the CoolAudio versions. (Following the schematic more carefully and noting the orientation of the jumper requirement differences.)

Thank you for your suggestions, time and consideration.
Cybercow - aka: Mark Davis

 "Don't let your talent take you where your character can't keep you."