Searching a simple VCA DIY project

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Hales
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Re: Searching a simple VCA DIY project

Post by Hales » Sun Jan 12, 2020 5:12 pm

Sorry I'm not sure how to do that… I've set the multimeter in DC mode at 20 and measured 2 pads of D2, is that correct?

adam
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Re: Searching a simple VCA DIY project

Post by adam » Sun Jan 12, 2020 5:19 pm

did you get 12v? i would put the black probe on the power pin gnd and the red on the output of the diode

it's easy to create shorts doing this on smd parts, if you connect the wrong thing to gnd, so be careful.

Hales
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Re: Searching a simple VCA DIY project

Post by Hales » Sun Jan 12, 2020 5:29 pm

[Edit] I didn't understand, no, multimeter say 0 between power pin gnd and D2 output.

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Re: Searching a simple VCA DIY project

Post by adam » Sun Jan 12, 2020 5:56 pm

ok, well you could continuity test the diode and see if it's facing the right way, has your diode got any orientation markings on?

Hales
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Re: Searching a simple VCA DIY project

Post by Hales » Sun Jan 12, 2020 6:06 pm

Yes, D2 has a line as orientation, I solder it with the line towards the bottom of the PCB.

Hales
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Re: Searching a simple VCA DIY project

Post by Hales » Sun Jan 12, 2020 6:13 pm

I’ve continuity between positive power pin and D2 "A-N$11" and between D2 "C-N$16" and L2 "N$16"

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Re: Searching a simple VCA DIY project

Post by adam » Sun Jan 12, 2020 6:49 pm

so you have continuity but no voltage (i don't know what the strings you posted mean, C-N$16 etc

Hales
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Re: Searching a simple VCA DIY project

Post by Hales » Sun Jan 12, 2020 6:55 pm

Capture d’écran 2020-01-13 à 00.52.29.png
I made a screenshot so you can see the labels I'm talking about.
No voltage, but it's not impossible that I'm making mistake with the setup of the multimeter.
Also, to avoid any confusion, I specify that the module is not electrically supplied at the moment.
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adam
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Re: Searching a simple VCA DIY project

Post by adam » Sun Jan 12, 2020 7:19 pm

ok, it's continuity through the diode in the right direction that we're looking for, if it's the wrong way round then there won't be continuity between n$11 on the power pin and c$16 on d2

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Re: Searching a simple VCA DIY project

Post by Hales » Sun Jan 12, 2020 7:34 pm

n$11 power pin > AN$11 > beep
n$11 power pin > CN$16 > no beep
CN$16 > 2N$16 > beep
L2 2N$16 > L2 1 VCC > beep

Hales
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Re: Searching a simple VCA DIY project

Post by Hales » Sun Jan 12, 2020 7:38 pm

You say that there should be continuity between n$11 power pin and D2 CN$16 ?
I oriented the line of D2 on the grey side visible on PCB last screenshot.
Last edited by Hales on Sun Jan 12, 2020 7:43 pm, edited 1 time in total.

adam
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Re: Searching a simple VCA DIY project

Post by adam » Sun Jan 12, 2020 7:40 pm

yes, a diode only allows current to flow in one direction

want to try desoldering d2 and flipping it round?

be careful because you might toast it and need to remove it to fit a new one - if you happen to have a spare better to try a fresh one

Hales
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Re: Searching a simple VCA DIY project

Post by Hales » Sun Jan 12, 2020 7:49 pm

In continuity mode, black probe on CN$16, red on AN$11, multimeter show 130 without bip. Red probe on CN$16, black on AN$11 multimeter show 1 without bip.

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Re: Searching a simple VCA DIY project

Post by adam » Mon Jan 13, 2020 8:16 am

sounds like the diodes dead, it was probably the right way round though ;)

Hales
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Re: Searching a simple VCA DIY project

Post by Hales » Mon Jan 13, 2020 8:23 am

mmmh ok… so I need to find new diodes for replacement since I don't have one…
is there a way to get them elsewhere than on Mouser to avoid shipping costs?
I suspect same problem for Ripples D3 and D4, continuity test doesn't work…

adam
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Re: Searching a simple VCA DIY project

Post by adam » Mon Jan 13, 2020 8:50 am

ebay might be a good bet in this case, or octopart will show suppliers, farnell and rs have euro warehouses & both deliver to france for instance

Hales
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Re: Searching a simple VCA DIY project

Post by Hales » Mon Jan 13, 2020 9:28 am

In fact I still hesitate because I am not sure of the reliability of my tests with the multimeter. So far I have been testing continuity in continuity mode on my multimeter, I have now tested the diodes on diode test mode. I have the same results on Ripples and Veils: multimeter show around 130/135 with black probe on cathode, multimeter show 1 with red probe on cathode.

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Re: Searching a simple VCA DIY project

Post by adam » Mon Jan 13, 2020 10:37 am

yes, i thought you'd said ripples had 12v ok, so all your diodes are working?

Hales
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Re: Searching a simple VCA DIY project

Post by Hales » Mon Jan 13, 2020 10:49 am

Sorry, it's obvious that my lack of knowledge makes it difficult to answer yes or no to your question.
Could you answer this question with regard to the elements provided in my last message?
And yes, the initial question provided from Veils that doesn't "beep" in continuity function on my multimeter when I tested positive "VCC" ICs with positive power pin.
Same test on Ripples, my multimeter "beep".

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cackland
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Re: Searching a simple VCA DIY project

Post by cackland » Mon Jan 13, 2020 12:52 pm

I would suggest testing on 'mV' on your multimeter to see that the voltage is going through the diode from the pin on the power header to the opposite side of the diode. You want to test the difference between gnd and vcc. Black lead on the gnd header pin, red lead on the side of the diode shown.

Capture d’écran 2020-01-13 à 00-1.52.29.png
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Hales
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Re: Searching a simple VCA DIY project

Post by Hales » Tue Jan 14, 2020 9:14 am

This measure give no result, multimeter stay at 0. I’ve also tested black lead on the same gnd header pin and red lead on A-N$11, same result: 0.

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cackland
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Re: Searching a simple VCA DIY project

Post by cackland » Tue Jan 14, 2020 10:05 am

Ok what about testing the header pins themselves. Black on ground and red on + pin or - pin?

Hales
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Re: Searching a simple VCA DIY project

Post by Hales » Tue Jan 14, 2020 10:14 am

IMG_1293.JPG
Same results: 0. I post a photo, to be sure we are talking about the same mode on multimeter, I've tried with 200m and 2000m settings.
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Hales
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Re: Searching a simple VCA DIY project

Post by Hales » Tue Jan 14, 2020 10:19 am

Same test on Ripples gives me the same result.

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cackland
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Re: Searching a simple VCA DIY project

Post by cackland » Tue Jan 14, 2020 10:44 am

So you are not getting any voltage readings on your header pins?

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