MOTM

Hi all, 

I completed my first 'real' kit yesterday, the 101, but I've 
got some problems with it, hope you can help.

When powering up the module everything looks fine, the led 
is blinking. Btw, I double checked all the parts and 
polarity, all looks okay to me.


Problem 1: two of the pads of pots VR2 and VR4 are placed 
close together. The pads of VR4 look connected on the 
pcboard printing. The pads of VR2 look similar, but there's 
a very fine line intersecting the bridge between the pads. 
Are the pads of both V2 and VR4 supposed to be connected? 
Or other pots as well?

Problem 2: Measuring the white noise output, I get no more 
than 0.69 VAC, even when the trim pot is fully opened. I'm 
expected to get 0.85 VAC. When listening to the white noise 
output, it is several dB less louder than the pink noise 
output.

The S&H output seems to work, but since it depends on the 
white noise output, I'll wait with that until I get the 
level fixed.

Thanks for any help,
Robert

>
>
> Problem 1: two of the pads of pots VR2 and VR4 are placed
> close together. The pads of VR4 look connected on the
> pcboard printing. The pads of VR2 look similar, but there's
> a very fine line intersecting the bridge between the pads.
> Are the pads of both V2 and VR4 supposed to be connected?

Yes, look at the schematic.


> Or other pots as well?

No.

>
> Problem 2: Measuring the white noise output, I get no more
> than 0.69 VAC, even when the trim pot is fully opened. I'm
> expected to get 0.85 VAC.

That's because my DVM is better than you DVM :)

Really, that's OK: I have a very wide-bandwidth DVM (Fluke 77). Set the trimpot (ising your DVM)
to 0.5V



 When listening to the white noise
> output, it is several dB less louder than the pink noise
> output.

Yes, the manual is wrong about this (sorry!). These issues were discussed about 1 year ago (it's
in the archives).

Paul S.

On Friday 31 October 2003 15:28, Paul Schreiber wrote:
> > Problem 1: two of the pads of pots VR2 and VR4 are
> > placed close together. The pads of VR4 look connected
> > on the pcboard printing. The pads of VR2 look similar,
> > but there's a very fine line intersecting the bridge
> > between the pads. Are the pads of both V2 and VR4
> > supposed to be connected?
>
> Yes, look at the schematic.

I did. Black lines on white paper. ;)
I started an electronics course, so probably more luck next 
time.

> > Problem 2: Measuring the white noise output, I get no
> > more than 0.69 VAC, even when the trim pot is fully
> > opened. I'm expected to get 0.85 VAC.
>
> That's because my DVM is better than you DVM :)

Duh! ;)

> Really, that's OK: I have a very wide-bandwidth DVM
> (Fluke 77). Set the trimpot (ising your DVM) to 0.5V

You want me do trim put such that the white noise output 
measures 0.5V on my DVM? Will do.

Btw, does this mean that I'll have to find another DVM? It 
all started with the incorrect reading on the meter. I 
mean, will I get more of these problems with other modules?


>  When listening to the white noise
>
> > output, it is several dB less louder than the pink
> > noise output.
>
> Yes, the manual is wrong about this (sorry!). These
> issues were discussed about 1 year ago (it's in the
> archives).

Ah, I found it.

Okay, thanks Paul. You what this means, yes? It means that 
my 101 simply works! :))

- Robert