Analogue-sequencer

Folks,

v3.90 rev 4, in files section now, sorts out the scrambled display 
and lack of control that sometimes occurs when a P3 is powered on 
for the first time without doing a system initialise.
This isn't of much practical use unless you want to take the backup 
battery out for a while to randomise the contents of memory.

I get married tomorrow, so I'll be away for the next few weeks.
If I find an internet kiosk in Mexico I might check my email 
occasionally, but not if the wife catches me...
I've left Paul Nagle in charge of the list while I'm away, so no 
messing about, or he'll boot you off ;-)

Cheers,
Colin f

> I get married tomorrow, so I'll be away for the next few weeks.

Colin,

All the very best to you and your soon to be ex g/f. :->) 

Hope the day goes well, and that you enjoy a well earned Honeymoon. 

Good Luck 

Andy

--- In analogue-sequencer@yahoogroups.com, "colinfraser_com" 
<colin@c...> wrote:

> I get married tomorrow, so I'll be away for the next few weeks.
> If I find an internet kiosk in Mexico I might check my email 
> occasionally, but not if the wife catches me...

Congrats... and don't drink the water when in Mexico!  :)

colinfraser_com (03:26 am 3/26/2004) wrote:

 >I get married tomorrow...

WAHOOO!!!!!!!!!!!!!!!!!

On Fri, 26 Mar 2004, Andy Wilson wrote:

> All the very best to you and your soon to be ex g/f. :->)
>
> Hope the day goes well, and that you enjoy a well earned Honeymoon.

i echo those sentiments... and thanks for all the time you spend answering
my silly questions, especially before this HUGE and awesome day... thanks
colin!

bleep.
out.

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

WHERE ABOUT IN MEXICO COLIN? JUST WONDERING. CANCUN IS SUPER. HOPE YOU HAVE FUN AND BEST LUCK.


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hi all...

my p3 is *almost* alive... there seems to be some issue with the fuse. the
only way i can bring it to life is to short the fuse (currently being done
via my multimeter). my power supply is 9VDC at 800mA... that's not enough
power to trip the 1/2 amp fuse. however, measured at the jacks, the power
seems to be SIX AMPS!!! that should be plenty to trip the fuse... but the
strange thing is that, across the fuse, the amperage looks exactly
right... 800mA. the P3 also comes to life when i've got the positive lead
connected to the right side of the fuse and the negative lead to the right
side of D6. (the reason i'm doing amperage measurements is because my
multimeter sucks and won't read voltage when the current is greater than
450mA.)

fyi, here's the fuse i'm using:
http://www.cooperet.com/pdfs_html/MCR_Specs.PDF

thanks for any help...

fred.

bleep.
out.

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

interstingly, it seems that when i short the fuse with just a wire, it
makes the P3 unhappy... but when it's through the multimeter (radio shack
LCD auto range digital), it's perfectly happy.

argh!

bleep.
out.

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

Hi Fred, 

In the absence of Colin, who is now drifting away in marital bliss, 
I'll  see if I can help. 

First. Get yourself a multimeter that works :->) 

> my p3 is *almost* alive... there seems to be some issue with the  
fuse. 
> the only way i can bring it to life is to short the fuse (currently 

> being done via my multimeter). my power supply is 9VDC at  800mA... 


The psu is plenty powerful enough for the P3. Sounds like there is a  
fault with your fuse. 

> that's not enough power to trip the 1/2 amp fuse. however,  
measured at 
> the jacks, the power seems to be SIX AMPS!!! that should be  plenty 
to 
> trip the fuse...  

But this sounds like you are just shorting the psu with the meter. 
The  current will increase but the voltage will collapse to nothing, 
and  eventually your power supply will burn out. It's not a good idea 
to  short the input jack. 

but the strange thing is that, across the fuse, the 
> amperage looks exactly right... 800mA. the P3 also comes to life  
when 
> i've got the positive lead connected to the right side of the fuse 
and 
> the negative lead to the right side of D6.  

The fact that you're reading that much current through the meter  
indicates that the fuse is not working. 

(the reason i'm doing 
> amperage measurements is because my multimeter sucks and  won't 
read 
> voltage when the current is greater than 450mA.) 

I don't really understand this statement, but I reckon it's time to  
beg/borrow or steal a working meter. 

You could just try removing the fuse and inserting a wire link in 
it's  place. I know you say that you have tried shorting the fuse, 
but  maybe there is a broken track or solder pad around the fuse. You 
 don't *really* need a fuse at all. It'd just there as an extra 
safety  precaution. You need to check the continuity with a working 
meter.  Check that one end of the fuse pad actually gets to D6 anode, 
and  the other end actually gets to the input socket. 

Also check the voltage on the output of the regulator. It should be  
+5V wrt ground. 

Hope this helps 

Good luck 

Andy 

---

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

yOn Mon, 29 Mar 2004, Andy Wilson wrote:

> In the absence of Colin, who is now drifting away in marital bliss,
> I'll  see if I can help.

thanks andy!

> First. Get yourself a multimeter that works :->)

it works fine... it's just that on the 10A input, i can't measure voltage.
it's in the design. the other positive input can only handle a 450 mA
current, also in the design... obviously, this is not enough for what i'm
using it for now.

> The psu is plenty powerful enough for the P3. Sounds like there is a
> fault with your fuse.

maybe i will try your suggestion of the wire link... at what point is
current dangerous for the p3? i noticed my voltage regulator getting
*very* hot during all this...

> But this sounds like you are just shorting the psu with the meter.
> The  current will increase but the voltage will collapse to nothing,
> and  eventually your power supply will burn out. It's not a good idea
> to  short the input jack.

uhhhh... :) oops. though handy with a soldering iron, i am almost
completely ignorant about electronics...

> but  maybe there is a broken track or solder pad around the fuse. You
>  don't *really* need a fuse at all. It'd just there as an extra
> safety  precaution. You need to check the continuity with a working
> meter.  Check that one end of the fuse pad actually gets to D6 anode,
> and  the other end actually gets to the input socket.

i will check that, thanks.

fred.

bleep.
out.

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

Hi Fred,

> it works fine... it's just that on the 10A input, i can't measure 
voltage.

OK, it sounds like your meter has three inputs: a common, or ground; 
a Voltage/resistance/mA; and a High current 10A input. When you 
connect the probes to the common and 10A input, this can only measure 
current going through a circuit, it cannot as you say, measure 
voltage.

What you need to do is connect the meter probes to the common and the 
V/Ohm/mA input and set the meter to measure *voltage* not current. 
Now apply voltage to the dc input jack of the P3 and measure the 
voltage between the 2 input pins. It should measure about 9V. If 
that's OK, then put your +ve probe on the anode of D6 (the end 
without the stripe), and the -ve probe on 0V. This should also 
measure about +9V. If you move the +ve probe to the striped end of 
D6, this should be about +8.3V.

Now measure the output pin 3 of the voltage regulator 7805 (you can 
measure this at the striped end of D1 if you have used it). This 
should be +5V. If this all checks out, then chances are the power 
supply is OK.....but......

If the voltage regulator is getting really hot, and you have mounted 
it on a heatsink, then it seems that your circuit is pulling too much 
current. With the circuit running properly, you should be able to 
hold your finger on the regulator without burning it.

Check the orientation of the Zener diode D1 if you have used it (i.e. 
make sure you have put it in the right way round). If it's the wrong 
way round, this will cause a near short of the voltage regulator, and 
cause it to get hot.

Let us know how you get on

All the best

Andy
---

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

On Tue, 30 Mar 2004, Andy Wilson wrote:

> What you need to do is connect the meter probes to the common and the
> V/Ohm/mA input and set the meter to measure *voltage* not current.
> Now apply voltage to the dc input jack of the P3 and measure the
> voltage between the 2 input pins. It should measure about 9V. If

did that... 7.6v. even after i've removed the fuse, replaced it with a
wire link, and removed D1, the regulator gets very hot and the P3 does not
appear to power up. looking at the data sheet, the regulator's ground is
the middle pin. from that to the third pin (output), the voltage registers
as .776v.

my theory is that while i was attempting to work with the P3 while
shorting the fuse through my multimeter, i toasted the power supply
somehow. the voltage has dropped, and now it's outputting SIX amps. my
other theory is that this has happend AND i've toasted the voltage
regulator in the process. the rest of the chips feel fine. no magic smoke,
no heat.

> Now measure the output pin 3 of the voltage regulator 7805 (you can
> measure this at the striped end of D1 if you have used it). This
> should be +5V. If this all checks out, then chances are the power
> supply is OK.....but......

from pin 1 (input) to pin 3 (output), the voltage it's outputting is 5.6.

thanks for your help andy,
fred.

bleep.
out.

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

At 06:35 PM 3/31/04 -0600, you wrote:
>
>On Tue, 30 Mar 2004, Andy Wilson wrote:
>
>> What you need to do is connect the meter probes to the common and the
>> V/Ohm/mA input and set the meter to measure *voltage* not current.
>> Now apply voltage to the dc input jack of the P3 and measure the
>> voltage between the 2 input pins. It should measure about 9V. If
>
>did that... 7.6v. even after i've removed the fuse, replaced it with a
>wire link, and removed D1, the regulator gets very hot and the P3 does not
>appear to power up. looking at the data sheet, the regulator's ground is
>the middle pin. from that to the third pin (output), the voltage registers
>as .776v.


.776V sounds like 1 diode drop.  I bet you have a diode mounted backwards
right near the power supply

Dave Magnuson



Resonant Frequency:
resfreq@hoohahrecords.com
http://www.hoohahrecords.com/resfreq/index.html

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

Fred,

> >the middle pin. from that to the third pin (output), the voltage 
registers
> >as .776v.
> 
> 
> .776V sounds like 1 diode drop.  I bet you have a diode mounted 
backwards
> right near the power supply

Dave's right. Does sound like a diode drop. But you say that it 
measures 0.776V even when after you have removed the zener D1 so 
that's out of the equation. Next check the orientation of the 4 
diodes around the midi/sync socket. If this all checks out OK, then 
hopefully you have socketed all of the ICs. If so, then I would 
remove all the chips, the IDC connectors and the backup battery then 
remeasure the voltage at the regulator output. If the output still 
measures low, then suspect the regulator itself.

If it's OK at this point, and you get the required +5V, I would 
insert the IDC connectors one by one; each time powering up and 
checking the +5V. It would still be worth doing this , even if all 
your chips are soldered in, just to check the integrity of the ribbon 
connectors and associated boards.

If these all check out OK, then re-insert the chips one by one, each 
time powering off when you insert the chips, then switching back on 
and checking the regulator output. See if any of the chips drag the 
voltage down. Leave the microprocessor till last.

Let us know how you get on.

Good luck

Andy
---

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

On Thu, 1 Apr 2004, Dave Magnuson wrote:

> .776V sounds like 1 diode drop.  I bet you have a diode mounted backwards
> right near the power supply

i double checked... both D1 and D6 are in correctly, unless the PCB is
wrong... (well, now D1 has been removed). but there are diodes in the
voltage regulator... maybe it's shot...

bleep.
out.

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