Analogue-sequencer

> i went through all the parts this morning and most things look fine. the
> switches are a little small, but maybe this could be compensated for by
> some fancy drilling...

Which type of switches did you get ? Standard tacts ?
If you do some drilling, make sure to solder the switch legs enough to
reconnect the top and bottom pads if you break the thru-hole plating.

Cheers,
Colin f



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>>1) C12 is not specified on the BOM but it *is* on the PCB (near U3). what
value cap goes there?




same as c14: 100n ceramic disc

no idea how i know that.  for some reason ive fitted that, and i wouldnt have just guessed either (im not that knowlegable) 

it must have been on some document i read.

>>2) C7 is an electrolytic can, but on the PCB it looks like it's supposed
to be a ceramic disc... except the cathode is marked... ???

i have an electrolytic fitted to my p3

>>3) C15 is supposed to be a ceramic disc, but on the PCB it looks like it's
supposed to be an electrolytic can...

i have an electrolytic. 10uf, same as c7.  the BOM certaily states a ceramic disk.  i dont have the pled, but if you look at:

http://www.colinfraser.com/p3/p3-build-6.htm

then its an electrolytic that colins using there.  


>>4) are we supposed to screw the voltage regulator down to the pcb or just
bend it down?

i put an m3 bolt through, with a small ammount of heat transfer paste between the regulator and the sink.  dont know if this were the correct thing to do though.


It should be noted that im a novice, and hence, my comments shoudl be taken carefully ;)

Julian


[Non-text portions of this message have been removed]

>>same as c14: 100n ceramic disc.  no idea how i know that.  

still cant work out where i got that from, but the schematics:

http://www.colinfraser.com/p3/pdf/p3-sch-mainbrd.pdf

dont contradict.

julian


[Non-text portions of this message have been removed]

hi there...

things are beginning to come together! but i've got a couple of questions
about capacitors...

1) C12 is not specified on the BOM but it *is* on the PCB (near U3). what
value cap goes there?

2) C7 is an electrolytic can, but on the PCB it looks like it's supposed
to be a ceramic disc... except the cathode is marked... ???

3) C15 is supposed to be a ceramic disc, but on the PCB it looks like it's
supposed to be an electrolytic can...

4) are we supposed to screw the voltage regulator down to the pcb or just
bend it down?

thanks,
f.

bleep.
out.

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On Thu, 11 Mar 2004, Colin f wrote:

> Which type of switches did you get ? Standard tacts ?
> If you do some drilling, make sure to solder the switch legs enough to
> reconnect the top and bottom pads if you break the thru-hole plating.

yup... thanks for the tip... i'm thinking we could also do a hybrid
drill... use the circular caps ala paul maddox, but still in the
screen-on-the-right layout...

bleep.
out.

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http://thirdwavecollective.com

there's too much crap that's wrong... i'll put an actual real one up there
sometime next week... sorry for any inconvenience...

bleep.
out.

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http://thirdwavecollective.com

thanks julian!!!

bleep.
out.

---
http://leichenfeld.iuma.com
http://thirdwavecollective.com

> 1) C12 is not specified on the BOM but it *is* on the PCB 
> (near U3). what
> value cap goes there?

It was originally meant to be a 100n ceramic cap to decouple the RAM
chips.
I dropped it from the BoM because I wasn't certain about the leakage
current - whether it would cause the battery to drain prematurely. But
since then I discovered it would be no problem.
So you can fit it if you like, or not.

> 2) C7 is an electrolytic can, but on the PCB it looks like 
> it's supposed
> to be a ceramic disc... except the cathode is marked... ???

That one is an electrolytic - it's square on the silkscreen because I
was thinking of specifying an axial cap, but then couldn't get the legs
far enough apart. I'l change it to a radial symbol next time...
 
> 3) C15 is supposed to be a ceramic disc, but on the PCB it 
> looks like it's
> supposed to be an electrolytic can...

The ceramic C15 was on a prototype board. It was dropped before the
first production run, but I forgot it was on the BoM until round two.
On the round two boards I added the PLED de-coupling cap as C15, which
is a 10uF radial electrolytic.
 
> 4) are we supposed to screw the voltage regulator down to the 
> pcb or just
> bend it down?

It depends on whether your heatsink allows it or not.
If you can fit a screw in there, it's sensible to screw it down.
The heatsinks I use don't have space to get a screw in, so I just bend
the legs over so it all sits in the right place.

Cheers,
Colin f