Analogue-sequencer

Hey Fred,

How's it going with your P3? Have you got it running yet?

Andy
--
Andy Wilson
http://www.techman.synth.net
mailto:andy@techman.synth.net

On Fri, 9 Apr 2004, Andy Wilson wrote:

> How's it going with your P3? Have you got it running yet?

got a new power supply and a new voltage regulator... and *nothing.* i get
voltage across D6, but nothing else... i get erratic readings from the
voltage regulator... either zero or a number that fluctuates beneath 1
volt...

i now have no clue what to do...

bleep.
out.

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

> got a new power supply and a new voltage regulator... and *nothing.* i
> get voltage across D6, but nothing else... i get erratic readings from
> the voltage regulator... either zero or a number that fluctuates
> beneath 1 volt...

Ok, something's not right.
First, when you say you messure the voltage across D6, what do you get?
If the voltage regulator is behaving eratically its down to one of two
things;1) Bad input voltage (not enough or too much)
2) Too much load (short circuit)

To prove which it is remove one end of D6 (PSU diode IIRC) and measure the
voltage of the regulator, both input and output.

I would suggest using an external PSu which can go from 6v upto around
12v, notmuch higher, ideally I would say a 9V regulated PSU.

Just my thoughts
Paul

On 9 Apr 2004 at 9:06, blip wrote:

> got a new power supply and a new voltage regulator... and *nothing.* i get
> voltage across D6, but nothing else... i get erratic readings from the
> voltage regulator... either zero or a number that fluctuates beneath 1
> volt...

Still sounds like you've got a near short on the output of the regulator, i.e. something 
is pulling too much current. Have you tried powering up the board without the IDC 
connectors plugged in? Do that, then measure the regulator output. If it's still low, 
then you know it's a problem on the Main board and not with the ancillary boards or 
ribbons.

If the result indicates that the main board is at fault, and you have soldered all the ICs 
in place; check your soldering very carefully. Look out for any solder bridges or 
splashes which may be making unwanted connections. If you have socketed your 
ICs, then remove them all, then power up the board, and measure the regulator 
output again. Check and recheck that *ALL* your ics are inserted the right way round.

Foe guidance, refer to the picture at the bottom of this page:

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

Once you've checked it, get someone else to check it again, if you can. A fresh pair 
of eyes can work wonders.


 A backwards IC could easily produce the symptoms you describe.

> 
> i now have no clue what to do...

Don't give up. It's well worth the effort.

All the best

Andy
--
Andy Wilson
http://www.techman.synth.net
mailto:andy@techman.synth.net

On Fri, 9 Apr 2004 Paul.Maddox.Mail-list@Synth.net wrote:

> Ok, something's not right.
> First, when you say you messure the voltage across D6, what do you get?
> If the voltage regulator is behaving eratically its down to one of two
> things;1) Bad input voltage (not enough or too much)
> 2) Too much load (short circuit)

9.1v. i'm using a regulated PS: 9v up to 1.1A

> To prove which it is remove one end of D6 (PSU diode IIRC) and measure the
> voltage of the regulator, both input and output.

hmm... it doesn't matter which, i'm assuming?

> I would suggest using an external PSu which can go from 6v upto around
> 12v, notmuch higher, ideally I would say a 9V regulated PSU.

that's what i'm using...

thanks for all your help everyone...

bleep.
out.

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

On Fri, 9 Apr 2004, Andy Wilson wrote:

> Still sounds like you've got a near short on the output of the regulator, i.e. something
> is pulling too much current. Have you tried powering up the board without the IDC
> connectors plugged in? Do that, then measure the regulator output. If it's still low,
> then you know it's a problem on the Main board and not with the ancillary boards or
> ribbons.

the last time i tried, the only thing plugged in was the PLED. but i'll
try it without as well. i'm pretty sure it's something on the main
board... the other boards seem very simple. the power goes to the voltage
regulator and just stops. i've scrutinized the solder joints on the
regulator and i can't find any shorts. also, it doesn't seem to matter
whether the reg. is screwed down to the pcb or not.

> If the result indicates that the main board is at fault, and you have soldered all the ICs
> in place; check your soldering very carefully. Look out for any solder bridges or
> splashes which may be making unwanted connections. If you have socketed your
> ICs, then remove them all, then power up the board, and measure the regulator
> output again. Check and recheck that *ALL* your ics are inserted the right way round.

everything worked fine at one point, then just stopped. i'm 100% sure of
the orientation of all ICs. i triple checked the sockets when i soldered
them in, and i triple checked the ICs before i inserted them and again
after.

what i fear is that when i was running it, somehow i fried something.
what, i don't know.

previously, i managed to get it to run by shorting the fuse through my
multimeter. i clipped the two leads onto the two ends of the fuse and
started messing with the keypad. after a while, everything just shut off.
i haven't been able to get anything out of it since. i *really* hope i
didn't toast the cpu.

>  A backwards IC could easily produce the symptoms you describe.

could a dead one? *shudder*

> Don't give up. It's well worth the effort.

oh i won't. despite these troubles, the P3 is the answer to many years of
pattern-based dreaming. :)

thanks a ton, everyone.

bleep.
out.

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

stand by


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

Hi Fred

On 9 Apr 2004 at 12:56, blip wrote:
> 
> everything worked fine at one point, then just stopped. i'm 100% sure of
> the orientation of all ICs. i triple checked the sockets when i soldered
> them in, and i triple checked the ICs before i inserted them and again
> after.
> 
> what i fear is that when i was running it, somehow i fried something.
> what, i don't know.

OK, so it appears that you have your ICs in sockets. That's good. Try removing them 
all, except the regulator, and power up again. Measure the output voltage of the 
regulator. What do you get?

If it's the required +5V, then the reg is working and there is no short across the rails 
on the board.

Next remove the power and start inserting ICs. You could start with the micro, just 
insert this and power up. Measure the reg o/p again. If it's still OK, the chances are 
your micro is still good. Power down again and put a few more ics in.check the supply 
rails gain. Keep going until you either find the chip which is dragging down the rails, or 
you get a fully populated board with the supply intact.

Keep us posted

Andy

--
Andy Wilson
http://www.techman.synth.net
mailto:andy@techman.synth.net

Blip,

> > To prove which it is remove one end of D6 (PSU diode IIRC) and measure
the
> > voltage of the regulator, both input and output.
>
> hmm... it doesn't matter which, i'm assuming?

nope, either will do.
It just stops the voltage going to the rest of the main PCB.

assuming disconnecting the diode makes the regulator spring to life try
this;-

Turn off,
Remove ALL the IC's and ALL connectors (lcd/switchs/etc)
Turn on, check regulator output.
Assuming its ok, turn off
Insert one IC,
Turn on,
check voltage,
assuming its ok, turn off,
insert another IC

if you manage to put in all the ICs and it's still ok, next plug in the IO
boards, one at a time again.

I hate to say this but, are all the IC's in the correct way round, I know it
sounds obvious, but I've done this myself.
Also check to make sure that the PCB isn't shorting against the case
anywhere, if possible test it on a wooden work bench or something.

Paul

> Next remove the power and start inserting ICs. You could start with the
micro, just
> insert this and power up. Measure the reg o/p again. If it's still OK, the
chances are
> your micro is still good. Power down again and put a few more ics in.check
the supply
> rails gain. Keep going until you either find the chip which is dragging
down the rails, or
> you get a fully populated board with the supply intact.

damn, that'll teach me to read a thread before replying!!

Paul

On 10 Apr 2004 at 23:34, Paul Maddox (Mail Lists) wrote:

> Blip,
> 
> > > To prove which it is remove one end of D6 (PSU diode IIRC) and measure
> the
> > > voltage of the regulator, both input and output.
> >
> > hmm... it doesn't matter which, i'm assuming?
> 
> nope, either will do.
> It just stops the voltage going to the rest of the main PCB.
> 

Unfortunately, it also stops any voltage getting to the regulator as well! D6 is on the 
input pin, not the output pin.;->(

Andy
--
Andy Wilson
http://www.techman.synth.net
mailto:andy@techman.synth.net

On Sat, 10 Apr 2004, Andy Wilson wrote:

> OK, so it appears that you have your ICs in sockets. That's good. Try removing them
> all, except the regulator, and power up again. Measure the output voltage of the
> regulator. What do you get?
>
> If it's the required +5V, then the reg is working and there is no short across the rails
> on the board.
>
> Next remove the power and start inserting ICs. You could start with the micro, just

thanks andy (and paul)... i'll try this tonight or tomorrow...

bleep.
out.

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

hi all...

so i took all of my ICs out of the board. the regulator now gives me a
very consistent -.326V from input (neg probe) to output (pos probe). from
ground to either input or output, i get 0V. i'm getting 9.5V across D6.

so the problem appears *not* to be an IC... what on earth could it be???
F1 is just a wire now, and D1 has been removed completely.

hmmm... i just tried something... with the power completely disconnected,
i'm getting -.326V from the regulator input to its output... is D1
supposed to have a wire link or something??? the picture of the completely
populated board on colin's site completely omits that diode.

somehow, the power seems not to be getting to the regulator at all... it's
getting through D6, but not into the regulator. there is plenty of solder
on the input pin, so the only thing i can think of is that somehow in
replacing the regulator, solder flux covered the through-hole plating and
some of the external track and thus the power's not getting from the track
to the pin... does that sound possible??? if so? how do i go about fixing
it?

thanks again all...

bleep.
out.

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

On 14 Apr 2004 at 18:14, blip wrote:

> hi all...

Hi Fred,
> 
> so i took all of my ICs out of the board. the regulator now gives me a
> very consistent -.326V from input (neg probe) to output (pos probe). from
> ground to either input or output, i get 0V. i'm getting 9.5V across D6.

When you say you are getting 9.5V 'across' D6 do you mean you are measuring 
voltage actually across the diode itself, or is one end of your probe at 0V? You should 
only be getting approx 0.7V 'across' D6 if it is forward biased. i.e. if the anode is more 
positive than the cathode (cathode's the stripey end). Have you checked that D6 is in 
the right way round? 9.5V across D6 sounds as if it's reversed biased, which would 
be why there's bugger all getting to the regulator.
> 
> so the problem appears *not* to be an IC... what on earth could it be???
> F1 is just a wire now, and D1 has been removed completely.
> 
> hmmm... i just tried something... with the power completely disconnected,
> i'm getting -.326V from the regulator input to its output... is D1
> supposed to have a wire link or something??? the picture of the completely
> populated board on colin's site completely omits that diode.

You can safely omit D1. It's there to prevent overvoltage getting to the ICs in case the 
regulator fails. A bit of belt and braces on Colin's part.

The -0.326V is probably due to residual  charge on electrolytic capacitor C13. BTW 
check that cap's in the right way round. Striped end is -ve so it's pointing away from 
the regulator.

Incidentally, when measuring voltage at certain points in the circuit; It's often more 
useful to take measurements with reference to ground. i.e. put you -ve probe on a 0V 
point and the +ve probe on the point you want to measure. For subsequent 
measurements, leave the -Ve probe where it is, and just move the +ve probe.
> 
> somehow, the power seems not to be getting to the regulator at all... it's
> getting through D6, but not into the regulator. there is plenty of solder
> on the input pin, so the only thing i can think of is that somehow in
> replacing the regulator, solder flux covered the through-hole plating and
> some of the external track and thus the power's not getting from the track
> to the pin... does that sound possible??? if so? how do i go about fixing
> it?

Try measuring the voltage actually on the regulator input pin itself.

OK. In the interest of investigating this further. I have just opened up my P3. Here are 
some measurements for you reference, which I've made, all referenced to 0V.

The wall wart I'm using is rated at 9VDC 1A. The off-load voltage output of this is 
actually 14.8V. In my circuit, I have installed fuse F1, and Zener diode D1.

Now, with the wall wart plugged in, and power turned on here are the voltages at 
various points referenced to  the anode of D1, my 0V reference point.

F1 input +13.1V
D6 anode +13.0V
D6 cathode (Striped end) +12.2V
Regulator input (Leftmost pin) +12.2V
Regulator Ground pin (middle pin) 0.0V
Regulator output pin (right most pin) +4.99V
Zener D1 Cathode +4.99V
Battery VB +ve +3.3V

Hope some of this helps.

Good luck

Andy

--
Andy Wilson
http://www.techman.synth.net
mailto:andy@techman.synth.net

Andy,

Thanks for the help you've been giving Fred so far.
I haven't really got anything to add beyond what you've already 
suggested, other than to confirm that D1 can be omitted and I 
usually don't fit it myself. I've heard of 78xx series regulators 
failing in such a way as to pass the input voltage directly to the 
output, which is what D1 will prevent. But I've never seen a 
regulator fail that way myself.

Cheers,
Colin f


--- In analogue-sequencer@yahoogroups.com, "Andy Wilson" <andy@t...> 
wrote:
> On 14 Apr 2004 at 18:14, blip wrote:
> 
> > hi all...
> 
> Hi Fred,
> > 
> > so i took all of my ICs out of the board. the regulator now 
gives me a
> > very consistent -.326V from input (neg probe) to output (pos 
probe). from
> > ground to either input or output, i get 0V. i'm getting 9.5V 
across D6.
> 
> When you say you are getting 9.5V 'across' D6 do you mean you are 
measuring 
> voltage actually across the diode itself, or is one end of your 
probe at 0V? You should 
> only be getting approx 0.7V 'across' D6 if it is forward biased. 
i.e. if the anode is more 
> positive than the cathode (cathode's the stripey end). Have you 
checked that D6 is in 
> the right way round? 9.5V across D6 sounds as if it's reversed 
biased, which would 
> be why there's bugger all getting to the regulator.
> > 
> > so the problem appears *not* to be an IC... what on earth could 
it be???
> > F1 is just a wire now, and D1 has been removed completely.
> > 
> > hmmm... i just tried something... with the power completely 
disconnected,
> > i'm getting -.326V from the regulator input to its output... is 
D1
> > supposed to have a wire link or something??? the picture of the 
completely
> > populated board on colin's site completely omits that diode.
> 
> You can safely omit D1. It's there to prevent overvoltage getting 
to the ICs in case the 
> regulator fails. A bit of belt and braces on Colin's part.
> 
> The -0.326V is probably due to residual  charge on electrolytic 
capacitor C13. BTW 
> check that cap's in the right way round. Striped end is -ve so 
it's pointing away from 
> the regulator.
> 
> Incidentally, when measuring voltage at certain points in the 
circuit; It's often more 
> useful to take measurements with reference to ground. i.e. put 
you -ve probe on a 0V 
> point and the +ve probe on the point you want to measure. For 
subsequent 
> measurements, leave the -Ve probe where it is, and just move the 
+ve probe.
> > 
> > somehow, the power seems not to be getting to the regulator at 
all... it's
> > getting through D6, but not into the regulator. there is plenty 
of solder
> > on the input pin, so the only thing i can think of is that 
somehow in
> > replacing the regulator, solder flux covered the through-hole 
plating and
> > some of the external track and thus the power's not getting from 
the track
> > to the pin... does that sound possible??? if so? how do i go 
about fixing
> > it?
> 
> Try measuring the voltage actually on the regulator input pin 
itself.
> 
> OK. In the interest of investigating this further. I have just 
opened up my P3. Here are 
> some measurements for you reference, which I've made, all 
referenced to 0V.
> 
> The wall wart I'm using is rated at 9VDC 1A. The off-load voltage 
output of this is 
> actually 14.8V. In my circuit, I have installed fuse F1, and Zener 
diode D1.
> 
> Now, with the wall wart plugged in, and power turned on here are 
the voltages at 
> various points referenced to  the anode of D1, my 0V reference 
point.

> 
> F1 input +13.1V
> D6 anode +13.0V
> D6 cathode (Striped end) +12.2V
> Regulator input (Leftmost pin) +12.2V
> Regulator Ground pin (middle pin) 0.0V
> Regulator output pin (right most pin) +4.99V
> Zener D1 Cathode +4.99V
> Battery VB +ve +3.3V
> 
> Hope some of this helps.
> 
> Good luck
> 
> Andy
> 
> --
> Andy Wilson
> http://www.techman.synth.net
> mailto:andy@t...

Hi Colin,


On 15 Apr 2004 at 17:08, colinfraser_com wrote:

> Andy,
> 
> Thanks for the help you've been giving Fred so far.

No problem.

Welcome back. Hope your tan doesn't fade too soon.

You've been back for at least 24 hours. I thought we'd be on V4.00 by now ;->)

All the best

Andy
--
Andy Wilson
http://www.techman.synth.net
mailto:andy@techman.synth.net

> Welcome back. Hope your tan doesn't fade too soon.

No tan here - I'm so fair skinned, I barely cast a shadow. Either I stay
out of the sun, or use factor 25.

> You've been back for at least 24 hours. I thought we'd be on 
> V4.00 by now ;->)

The 3 in the version number really refers to P3, so I'll have a bit of a
problem once we reach v3.99 !
I'll just have to make sure the ROM is full before then, and the
firmware therefore 'finished' ;-)

Cheers,
Colin f

Fred,

> When you say you are getting 9.5V 'across' D6 do you mean you are
measuring
> voltage actually across the diode itself, or is one end of your probe at
0V? You should
> only be getting approx 0.7V 'across' D6 if it is forward biased. i.e. if
the anode is more
> positive than the cathode (cathode's the stripey end). Have you checked
that D6 is in
> the right way round? 9.5V across D6 sounds as if it's reversed biased,
which would
> be why there's bugger all getting to the regulator.

gotta go with andy on this, the diode is in backwards.

Paul

On Thu, 15 Apr 2004, Paul Maddox (Mail Lists) wrote:

> > positive than the cathode (cathode's the stripey end). Have you checked
> that D6 is in
> > the right way round? 9.5V across D6 sounds as if it's reversed biased,
> which would
> > be why there's bugger all getting to the regulator.
>
> gotta go with andy on this, the diode is in backwards.

if the diode is in backwards, it's either defective or the PCB is wrong...
the striped end of the diode is at the striped endn of the marking on the
PCB.

bleep.
out.

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

On Thu, 15 Apr 2004, Andy Wilson wrote:

> When you say you are getting 9.5V 'across' D6 do you mean you are
> measuring voltage actually across the diode itself, or is one end of
> your probe at 0V? You should only be getting approx 0.7V 'across' D6 if
> it is forward biased. i.e. if the anode is more positive than the
> cathode (cathode's the stripey end). Have you checked that D6 is in the
> right way round? 9.5V across D6 sounds as if it's reversed biased, which
> would be why there's bugger all getting to the regulator.

both ends of my probe are on either end of the diode. i'll try measuring
the other way, with the -Ve end at ground.

also... last night i found that when the powersupply is plugged in but
switched off, i still have about 2V coming into the PCB! the only time it
goes away is when i fully unplug the PS. (and that's 2V across d6...
measuring the silly way i have been.)

> You can safely omit D1. It's there to prevent overvoltage getting to the ICs in case the
> regulator fails. A bit of belt and braces on Colin's part.

that's what i thought... thanks!

> The -0.326V is probably due to residual charge on electrolytic capacitor
> C13. BTW check that cap's in the right way round. Striped end is -ve so
> it's pointing away from the regulator.

ah, that makes sense. to my knowledge it's fine, but i'll check again to
make sure.

> Incidentally, when measuring voltage at certain points in the circuit;
> It's often more useful to take measurements with reference to ground.
> i.e. put you -ve probe on a 0V point and the +ve probe on the point you
> want to measure. For subsequent measurements, leave the -Ve probe where
> it is, and just move the +ve probe.

thanks much... i didn't know that until now. :) always glad of an
education.

> Try measuring the voltage actually on the regulator input pin itself.

i've tried this with the -Ve probe on the output of D6 with the +Ve probe
on the input pin. 0V. but maybe that's due to my measurement "technique."

> OK. In the interest of investigating this further. I have just opened up my P3. Here are
> some measurements for you reference, which I've made, all referenced to 0V.

thanks andy! my PS is 9V but i think i can adapt your measurements to see
where mine is off.

> Battery VB +ve +3.3V

that's working on mine at least. :)

> Hope some of this helps.

very much.

thanks so much, andy.

f.

bleep.
out.

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

On Thu, 15 Apr 2004, colinfraser_com wrote:

> Andy,
>
> Thanks for the help you've been giving Fred so far.

highly seconded. :)

bleep.
out.

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

> if the diode is in backwards, it's either defective or the 
> PCB is wrong...
> the striped end of the diode is at the striped endn of the 
> marking on the
> PCB.

It may be marked wrongly - I've seen one diode with the markings the
wrong way round before, and have heard of other people getting them, so
it's rare, but not impossible. If your meter has a diode testing mode,
I'd verify if the diode is functional.

Cheers,
Colin f

Hi Colin, 

Good to have you back - i realise that you however may well be of a different opinion ; )

Anyway,

My anicipation of the P3 is growing.  Its sitting there, ready to be used, but im resisting sketchily mounting it in a butchered shoebox in the knowlege that the hammonds are comming... I hope...

Anyway, im sure youd say if they were about, but im just checking...

Cheers, Julian


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

Hi Fred,

> > if the diode is in backwards, it's either defective or the 
> > PCB is wrong...

Well, we *know* the pcb is right, so as Colin suggests; either the diode D6 is wrongly 
marked, or it is faulty. i.e open circuit.. Have you got another one you can swap it 
with?

All the best

Andy

--
Andy Wilson
http://www.techman.synth.net
mailto:andy@techman.synth.net

Hi Julian,

> My anicipation of the P3 is growing.  Its sitting there, 
> ready to be used, but im resisting sketchily mounting it in a 
> butchered shoebox in the knowlege that the hammonds are 
> comming... I hope...
> 
> Anyway, im sure youd say if they were about, but im just checking...

Some cases went for machining before I left but I haven't heard from
Steve T yet.
I'll let you know when I do...

Cheers,
Colin f

an aux event should be added for each track such that the output of the
track can be modified by hamsters.

http://instruct1.cit.cornell.edu/courses/eceprojectsland/STUDENTPROJ/2002to2003/lil2/index.html

:)

bleep.
out.

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

On Fri, 16 Apr 2004, Andy Wilson wrote:

> Well, we *know* the pcb is right, so as Colin suggests; either the diode D6 is wrongly
> marked, or it is faulty. i.e open circuit.. Have you got another one you can swap it
> with?

hmm... no, but i guess i'll have to get one. this is lucky for you guys
though... it means i won't be bugging you all weekend. :)

bleep.
out.

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

> an aux event should be added for each track such that the output of 
> the track can be modified by hamsters.
> 
> 
http://instruct1.cit.cornell.edu/courses/eceprojectsland/STUDENTPROJ/2
002to2003/lil2/index.html
> 
> :)


LOL...now that's a randomizer :)

On 16 Apr 2004 at 15:58, blip wrote:

> On Fri, 16 Apr 2004, Andy Wilson wrote:
> 
> > Well, we *know* the pcb is right, so as Colin suggests; either the diode D6 is 
wrongly
> > marked, or it is faulty. i.e open circuit.. Have you got another one you can swap it
> > with?
> 
> hmm... no, but i guess i'll have to get one. this is lucky for you guys
> though... it means i won't be bugging you all weekend. :)

Well, as long as your power supply is *definitely* DC, and the +ve output of the supply 
*definitely* goes to the end with the fuse , then you could replace D6 with a wire link. 
It's there to allow the use of ac supplies  and to prevent reversing the supply to the 
regulator.

Careful though.

All the best

Andy
--
Andy Wilson
http://www.techman.synth.net
mailto:andy@techman.synth.net