Author Topic: Choral Reef not Chorusing  (Read 419 times)

WAXOU

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Choral Reef not Chorusing
« on: November 15, 2017, 05:35:03 AM »
Hi All,

So, this weekend I've finally built the Choral Reef, but the only sound that I can get is almost like if Flipper the Dolphin was inside and wanted to communicate ! A kind of a tiny whinning.
The bypass signal is Ok though.

i've double checked my soldering and it seems to be okay.

However they're are some voltages that  have not the value that they should have :
 
TLE2074CD4047BE
PINVPINV
14,6417,4
24,6420,2
34,4135,03
48,4247,58
54,6257,58
64,6367,58
74,6370
87,5580
97,0790
106,96103,77
110113,5
121,3120
134,7137,39
144,64140
MN3008 LM358N
17,61varies
23,523,75
67,333,47
77,340
805varies
93,7761,97
130,187varies
14088,42
5087 5088
PINVPINV
C0C8,42
B5,5B8,18
E5,2E7,58

Do you have any ideas on where to start the debugging ?

Thx

(In the meantime I'm gonna start the Tractor Beam, maybe I'll be better at it :))
« Last Edit: November 15, 2017, 09:28:16 AM by WAXOU »
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WAXOU

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Re: Choral Reef not Chorusing
« Reply #1 on: December 07, 2017, 03:29:09 PM »
So, I've put the board back on the workbench, but still no luck.

Voltages on Pins 8, 9, 10 and 12 of the TLE2074 seems weird.
Same on the 14 of the CD4047 and 13 of the mn3008.

The first time I've tried the board, I forgot the reverse cap on the switching board, could this have damaged something somehow ?




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Scruffie

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Re: Choral Reef not Chorusing
« Reply #2 on: December 08, 2017, 07:17:42 AM »
Pins 8, 9 & 10 of the TLE2074 are biased by the BBD output and there's a problem with the BBD's pin 13 input bias voltage (which affects its output voltage)

I would double check your reading of the 4047 pin 14, it's connected directly to the 3008 pin 1 and T1's emitter and they both look okay.

Post up some photos of your board.
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WAXOU

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Re: Choral Reef not Chorusing
« Reply #3 on: December 08, 2017, 10:53:17 AM »
Thx Scruffie for your answer.

You're right, the pin 14 on the CD4047 is at 7,65V, I must have failed the first time I mesured it.

Here are some pics.





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Scruffie

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Re: Choral Reef not Chorusing
« Reply #4 on: December 08, 2017, 11:16:49 AM »
I'm not 100% sure but is R14 a 3k3 rather than 33k? I can't see R17 in your photos but check the value of that too... and the value of R16 just to be sure.

In the mean time could you post a photo of the back of the board too please and can you also double check your 3008 pin 13 voltage.
« Last Edit: December 08, 2017, 11:18:34 AM by Scruffie »
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WAXOU

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Re: Choral Reef not Chorusing
« Reply #5 on: December 08, 2017, 01:48:10 PM »
So, I've checked for R14, R17 and R16, they have the right values.
Since I'm colorblind I had to desolder them to mesure them, so in the mean time I change the mn3008 socket to be sure.

Pin 13 of MN3008 is still at 0,19 V.

Here are the back of the board. I'm ashamed of showing this mess, with all the solder/desolder the board is quite ugly now.





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Scruffie

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Re: Choral Reef not Chorusing
« Reply #6 on: December 08, 2017, 01:59:43 PM »
Where did you source the 3008 from? And if you remove it and test pin 13 does the voltage change?
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WAXOU

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Re: Choral Reef not Chorusing
« Reply #7 on: December 08, 2017, 02:09:19 PM »
Well If I remove the Mn3008, pin 13 is at 7,5V.

So I'm guessing I've got a faulty Mn3008.
I've sourced it at banzai music in Germany, where I've purchased several mn3007 before, so I was confident.
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Scruffie

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Re: Choral Reef not Chorusing
« Reply #8 on: December 09, 2017, 08:15:38 PM »
It's certainly a possibility, unless there is a short on the board.

However I think I recall someone else getting some bad chips from Banzai so it's possible they currently have a poor source for these parts.
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WAXOU

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Re: Choral Reef not Chorusing
« Reply #9 on: December 11, 2017, 02:15:13 AM »
I will source another one and let you know if it resolves the issue.
Thanks again for your help.
To do is to be -- Descartes / To be is to do -- Sartre / Doo, bee, doo, bee, doo -- Sinatra