Author Topic: Q: Zero Point Micro Issue  (Read 1273 times)

1reeper

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Q: Zero Point Micro Issue
« on: July 01, 2013, 09:09:53 PM »
So I bought a ZPM board, populated it, boxed it, and had something odd happen.  Signal goes through, but with no delay nor modulation effects.  The signal just gets boosted a fair amount, quite cleanly too, might make a good boost if not for the other issue.

The 78l05 I bought heats up when it's plugged in and turned on.  Not enough to fry it, mind, it still puts out 5V just fine.

All the caps are the proper values, and so are the resistors (as far as I can tell). The regulator doesn't heat up when I pull the 2399 but that's not telling me much either.

I've done the standard checks for bridges and bad joints but found nothing.  This is confusing as hell.

I'd appreciate any help that's given.

Oh, and I put this in a 125B since that was on hand, so accidental grounding is fairly unlikely.

jkokura

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Re: Q: Zero Point Micro Issue
« Reply #1 on: July 02, 2013, 03:58:25 PM »
Couple things.

Can you verify you haven't made a wiring mistake? Also, your regulator shouldn't get very hot at all - are you sure you're using a proper power supply?

Also, good pictures of the PCB and voltage readings will be helpful.

Jacob
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1reeper

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Re: Q: Zero Point Micro Issue
« Reply #2 on: July 02, 2013, 08:33:42 PM »
Double checked my wiring with DMM to ensure connectivity, it all looks good.  And yeah, like I said, the regulator is taking 9V in and putting 5V out.  My power supply is the same wall wart I've used for all my pedals.

Pics:




Voltages: (the double dashes indicates where I couldn't get a consistent reading, likely due to the fact the regulator is heating up)



Odd voltages, yeah...

RobA

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Re: Q: Zero Point Micro Issue
« Reply #3 on: July 02, 2013, 09:48:27 PM »
...
Odd voltages, yeah...

Yeah. I just happen to have mine out testing it in another circuit. So, the way it's getting power is a little bit low. My supply voltage is only 8.5V, but my readings are different from yours for sure (posted below). Pin 4 0n the 61 has to be whacked because that's ground. Pin 7 and pin 3 on the 072 look suspicious and like there could be solder bridges there. Pins 7, 8, 9 on the PT2399 or off from mine too, but I don't know how much they move in different settings.

My voltage regulator doesn't get hot for sure. I think you must have a short that is drawing too much current.

TL061
1   --
2   4.07
3   3.9
4   0
5   3.88
6   4.26
7   4.27
8   8.54

PT2399
1   5.19
2   2.6
3   0
4   0
5   3.0
6   2.6
7   1.0
8   1.0
9   2.6
10   2.6
11   2.6
12   2.6
13   2.6
14   2.6
15   2.6
16   2.6
Affiliations: Music Unfolding (musicunfolding.com), software based effects and Rock•it Frog (rock.it-frog.com), DIY effects (coming soon).

jkokura

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Re: Q: Zero Point Micro Issue
« Reply #4 on: July 02, 2013, 10:14:19 PM »
Yeah,

The TL071 looks fine except you should be getting a clear 0 at pin 4.

The TL072 looks like there's an issue. You should have around 4.5 on pins 2 and 7.

Jacob
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RobA

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Re: Q: Zero Point Micro Issue
« Reply #5 on: July 02, 2013, 10:27:09 PM »
Didn't notice that i had messed up my copy and didn't get my numbers for the 072 in there (and I did mean 062 and not 061 -- shouldn't trust myself to type with one hand when writing down numbers.)

Here's the 072 values I have.
1   4.27
2    4.27
3    4.23
4    0
5    3.89
6    4.27
7    4.27
8    8.5
Affiliations: Music Unfolding (musicunfolding.com), software based effects and Rock•it Frog (rock.it-frog.com), DIY effects (coming soon).