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Jupiter 6 common no sound problem

Jupiter 6 common no sound problem

2012-04-03 by adhmzaiusz

Hi again,  so I found a messed up JP6 recently that I bought to try and get it up and running.  It turns on with all the LEDs Lfo lights blink etc, but seems to be frozen with no sound.  If I wait about 10 minutes it seems to unfreeze so I can push buttons and lights come on but still no sound.  I've been reading that this seems to be a common problem, and the suspect is the voltages that drive the digital side of the machine.

I measured the power supply and all voltages are within spec except one that I am a little curious about, the reset out of the power supply seems to be at a constant voltage (i think it was 5v maybe could've been 10v off the top of my head).  Being called a reset output makes me think that maybe this voltage isn't supposed to be a held voltage and should maybe be a triggered momentary pulse to reset the cpu or something like that?  Can anyone confirm how the reset out is supposed to behave, let me know if i'm on the right track and possibly give a little insight of how to remedy this common problem.  Thanks again!

Greg

Re: [vintagesynthrepair] Jupiter 6 common no sound problem

2012-04-03 by Malte Rogacki

Reset on the Jupiter-6

I believe it goes like this: The Reset voltage coming directly from the
Power Supply is indeed a fixed voltage. It just takes a little bit of time
to ramp up and then triggers the actual reset circuitry. The reason for
this is to allow the power supply (notably the +5V digital) to stabilize
before the computer is activated.

So what you need to do is to measure the reset directly at the processor.
This would be pin 9 at the processor; and here it should indeed be a short
+5V "spike" (more like 80ms length).


--

Re: [vintagesynthrepair] Jupiter 6 common no sound problem

2012-04-03 by jammie

reset should be a momentary pulse usually 5v if it is constant held high then it will be in constant reset plus being 10v for a cpu chip is to high a voltage so cpu could be damaged
Show quoted textHide quoted text
----- Original Message -----
From: adhmzaiusz
Sent: Tuesday, April 03, 2012 5:47 AM
Subject: [vintagesynthrepair] Jupiter 6 common no sound problem

Hi again, so I found a messed up JP6 recently that I bought to try and get it up and running. It turns on with all the LEDs Lfo lights blink etc, but seems to be frozen with no sound. If I wait about 10 minutes it seems to unfreeze so I can push buttons and lights come on but still no sound. I've been reading that this seems to be a common problem, and the suspect is the voltages that drive the digital side of the machine.

I measured the power supply and all voltages are within spec except one that I am a little curious about, the reset out of the power supply seems to be at a constant voltage (i think it was 5v maybe could've been 10v off the top of my head). Being called a reset output makes me think that maybe this voltage isn't supposed to be a held voltage and should maybe be a triggered momentary pulse to reset the cpu or something like that? Can anyone confirm how the reset out is supposed to behave, let me know if i'm on the right track and possibly give a little insight of how to remedy this common problem. Thanks again!

Greg

RE: [vintagesynthrepair] Jupiter 6 common no sound problem

2012-04-03 by Lorne Hammond

I could be way off my understanding if its like the tr-909 that using
capacitors and zeners to a dual transistor set, to hold the voltage back
until it builds up to 5 volts.  Then the transistors unleash a ping
(discharging the cap) down the pipe to the cpu reset to wake up and boot.
The idea is to prevent scrambling memory and circuits with incorrect
voltages, so it's a protective gate that wont let it boot until a stable and
correct voltage is available for its operation.  

Bad cap? Bad zener? Bad transistor?  Replace all?  

 

Brian Castro showed me that there are also issues with thin traces that run
under the big caps in the 909 PS that idiots like me sometimes over
heat/overcooking solder for a "big' mechanical support for big caps, melting
delicate traces and then it needs bridging to fix.  Because the trace is
hidden under the big caps most people miss the damage, but a continuity
trace reveals it.  But it doesn't sound like you have that (symptom no reset
5v ever).

 

Lorne "caveat: barely knows what he is doing" in Canada
Show quoted textHide quoted text
From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of jammie
Sent: Tuesday, April 03, 2012 3:34 AM
To: vintagesynthrepair@yahoogroups.com
Subject: Re: [vintagesynthrepair] Jupiter 6 common no sound problem

 

  

reset should be a momentary pulse usually 5v if it is constant held high
then it will be in constant reset plus being 10v for a cpu chip is to high a
voltage so cpu could be damaged

----- Original Message ----- 

From: adhmzaiusz <mailto:adhmzaiusz@...>  

To: vintagesynthrepair@yahoogroups.com 

Sent: Tuesday, April 03, 2012 5:47 AM

Subject: [vintagesynthrepair] Jupiter 6 common no sound problem

 

  

Hi again, so I found a messed up JP6 recently that I bought to try and get
it up and running. It turns on with all the LEDs Lfo lights blink etc, but
seems to be frozen with no sound. If I wait about 10 minutes it seems to
unfreeze so I can push buttons and lights come on but still no sound. I've
been reading that this seems to be a common problem, and the suspect is the
voltages that drive the digital side of the machine.

I measured the power supply and all voltages are within spec except one that
I am a little curious about, the reset out of the power supply seems to be
at a constant voltage (i think it was 5v maybe could've been 10v off the top
of my head). Being called a reset output makes me think that maybe this
voltage isn't supposed to be a held voltage and should maybe be a triggered
momentary pulse to reset the cpu or something like that? Can anyone confirm
how the reset out is supposed to behave, let me know if i'm on the right
track and possibly give a little insight of how to remedy this common
problem. Thanks again!

Greg

Re: [vintagesynthrepair] Jupiter 6 common no sound problem

2012-04-03 by Malte Rogacki

So did I get this right:

At first the machine seems to be completely locked up?

Then after a while the controls (buttons, LED's and so on) start to work
but there's still no sound?

There's one thing to keep in mind: The processors of the voice boards need
their reset pulse, too. They are supplied with that pulse from the main
processor board. So break out the oscilloscope and measure the situation on
pin 9 of all three processors.
If you have the service manual the reset procesure and the components are
described on page 2b.

Re: Jupiter 6 common no sound problem

2012-04-04 by adhmzaiusz

Yea, its locked up for the most part.  Lfo 2 speed can still be adjusted immediately, but it seemed that after I wait a while the panel controls seem to unlock, its not perfect as it seems that the number select buttons only work 1, 6-8.  So 2-5 don't work.

Anyway, when I scope the reset inputs of the 3 CPUs I don't a locked voltage, which is normal.  When I power on the machine i can see the voltage jump as a spike on each reset.  So I'm assuming the reset works, as outlined on page 2b.

My scope is only a 20mhz but i can scope the other pins of the main cpu and i see what looks like all sorts of activity looks like pulse waves etc which I assume is normal.

I'm not so familiar with digital stuff, so i don't really know where to begin.  I was hoping when I bought this that it would just be a failed power supply!  Oh well 

Any further ideas? :)

greg

--- In vintagesynthrepair@yahoogroups.com, Malte Rogacki <gacki@...> wrote:
Show quoted textHide quoted text
>
> So did I get this right:
> 
> At first the machine seems to be completely locked up?
> 
> Then after a while the controls (buttons, LED's and so on) start to work
> but there's still no sound?
> 
> There's one thing to keep in mind: The processors of the voice boards need
> their reset pulse, too. They are supplied with that pulse from the main
> processor board. So break out the oscilloscope and measure the situation on
> pin 9 of all three processors.
> If you have the service manual the reset procesure and the components are
> described on page 2b.
>

Re: Jupiter 6 common no sound problem

2012-04-04 by adhmzaiusz

Actually I'd like to add that when it unfreezes its not just about fully waiting it out, I think its after a while + flipping SW1. Also it seems the only led that doesn't do anything is LFO1 rate.  But that might be something else to fix later...

--- In vintagesynthrepair@yahoogroups.com, "adhmzaiusz" <adhmzaiusz@...> wrote:
Show quoted textHide quoted text
>
> Yea, its locked up for the most part.  Lfo 2 speed can still be adjusted immediately, but it seemed that after I wait a while the panel controls seem to unlock, its not perfect as it seems that the number select buttons only work 1, 6-8.  So 2-5 don't work.
> 
> Anyway, when I scope the reset inputs of the 3 CPUs I don't a locked voltage, which is normal.  When I power on the machine i can see the voltage jump as a spike on each reset.  So I'm assuming the reset works, as outlined on page 2b.
> 
> My scope is only a 20mhz but i can scope the other pins of the main cpu and i see what looks like all sorts of activity looks like pulse waves etc which I assume is normal.
> 
> I'm not so familiar with digital stuff, so i don't really know where to begin.  I was hoping when I bought this that it would just be a failed power supply!  Oh well 
> 
> Any further ideas? :)
> 
> greg
> 
> --- In vintagesynthrepair@yahoogroups.com, Malte Rogacki <gacki@> wrote:
> >
> > So did I get this right:
> > 
> > At first the machine seems to be completely locked up?
> > 
> > Then after a while the controls (buttons, LED's and so on) start to work
> > but there's still no sound?
> > 
> > There's one thing to keep in mind: The processors of the voice boards need
> > their reset pulse, too. They are supplied with that pulse from the main
> > processor board. So break out the oscilloscope and measure the situation on
> > pin 9 of all three processors.
> > If you have the service manual the reset procesure and the components are
> > described on page 2b.
> >
>

Progress Re: Jupiter 6 common no sound problem

2012-04-18 by adhmzaiusz

Hey everyone, just wanted to mention that I've made some progress with my JP6. Since I got it I always thought it was a little strange that on the 4 voice board the slave cpu was socketed when both the other cpus werent, so I decided to pop it out and reseat it just for the heck of it. While i was at it i reseated the Roland "B" ic (i think it is a eprom) as well.  When I rebooted I was surprised to see that it finished autotune after about approx 10 seconds and there was sound.  
I think that when the JP6s freeze with the lfo they are locked up because they can't finish autotuning for any reason.  Anyway, my 4 voice board seems to be quite messed up, almost sounds like everything is high pitched and non cv controlled.  I guess that will be next on the list to sort out.

Greg

--- In vintagesynthrepair@yahoogroups.com, "adhmzaiusz" <adhmzaiusz@...> wrote:
Show quoted textHide quoted text
>
> Yea, its locked up for the most part.  Lfo 2 speed can still be adjusted immediately, but it seemed that after I wait a while the panel controls seem to unlock, its not perfect as it seems that the number select buttons only work 1, 6-8.  So 2-5 don't work.
> 
> Anyway, when I scope the reset inputs of the 3 CPUs I don't a locked voltage, which is normal.  When I power on the machine i can see the voltage jump as a spike on each reset.  So I'm assuming the reset works, as outlined on page 2b.
> 
> My scope is only a 20mhz but i can scope the other pins of the main cpu and i see what looks like all sorts of activity looks like pulse waves etc which I assume is normal.
> 
> I'm not so familiar with digital stuff, so i don't really know where to begin.  I was hoping when I bought this that it would just be a failed power supply!  Oh well 
> 
> Any further ideas? :)
> 
> greg
> 
> --- In vintagesynthrepair@yahoogroups.com, Malte Rogacki <gacki@> wrote:
> >
> > So did I get this right:
> > 
> > At first the machine seems to be completely locked up?
> > 
> > Then after a while the controls (buttons, LED's and so on) start to work
> > but there's still no sound?
> > 
> > There's one thing to keep in mind: The processors of the voice boards need
> > their reset pulse, too. They are supplied with that pulse from the main
> > processor board. So break out the oscilloscope and measure the situation on
> > pin 9 of all three processors.
> > If you have the service manual the reset procesure and the components are
> > described on page 2b.
> >
>

Re: [vintagesynthrepair] Progress Re: Jupiter 6 common no sound problem

2012-04-18 by jammie

check the cv dac and the sample and hold multiplexers
Show quoted textHide quoted text
----- Original Message -----
From: adhmzaiusz
Sent: Wednesday, April 18, 2012 2:06 PM
Subject: [vintagesynthrepair] Progress Re: Jupiter 6 common no sound problem

Hey everyone, just wanted to mention that I've made some progress with my JP6. Since I got it I always thought it was a little strange that on the 4 voice board the slave cpu was socketed when both the other cpus werent, so I decided to pop it out and reseat it just for the heck of it. While i was at it i reseated the Roland "B" ic (i think it is a eprom) as well. When I rebooted I was surprised to see that it finished autotune after about approx 10 seconds and there was sound.
I think that when the JP6s freeze with the lfo they are locked up because they can't finish autotuning for any reason. Anyway, my 4 voice board seems to be quite messed up, almost sounds like everything is high pitched and non cv controlled. I guess that will be next on the list to sort out.

Greg

--- In vintagesynthrepair@yahoogroups.com, "adhmzaiusz" wrote:
>
> Yea, its locked up for the most part. Lfo 2 speed can still be adjusted immediately, but it seemed that after I wait a while the panel controls seem to unlock, its not perfect as it seems that the number select buttons only work 1, 6-8. So 2-5 don't work.
>
> Anyway, when I scope the reset inputs of the 3 CPUs I don't a locked voltage, which is normal. When I power on the machine i can see the voltage jump as a spike on each reset. So I'm assuming the reset works, as outlined on page 2b.
>
> My scope is only a 20mhz but i can scope the other pins of the main cpu and i see what looks like all sorts of activity looks like pulse waves etc which I assume is normal.
>
> I'm not so familiar with digital stuff, so i don't really know where to begin. I was hoping when I bought this that it would just be a failed power supply! Oh well
>
> Any further ideas? :)
>
> greg
>
> --- In vintagesynthrepair@yahoogroups.com, Malte Rogacki wrote:
> >
> > So did I get this right:
> >
> > At first the machine seems to be completely locked up?
> >
> > Then after a while the controls (buttons, LED's and so on) start to work
> > but there's still no sound?
> >
> > There's one thing to keep in mind: The processors of the voice boards need
> > their reset pulse, too. They are supplied with that pulse from the main
> > processor board. So break out the oscilloscope and measure the situation on
> > pin 9 of all three processors.
> > If you have the service manual the reset procesure and the components are
> > described on page 2b.
> >
>

Progress Re: Jupiter 6 common no sound problem

2012-04-19 by adhmzaiusz

Well, it may appear I've run into a potential happy mistake.  Today when I tried my next attempt to get my JP6 on its feet, I realized that yesterday when I replanted the slave cpu pin#1 was bent right out and not even in the socket.  So I fixed it and plugged it back in, and what do you know it locks up again.  So i bent back pin 1 again to see what happens, and what do you know it unlocks itself without pin 1 plugged in.  So strange.  I then replaced the level shifter IC10 (MC14504) figuring maybe it was all stuck high, but still no difference.  Otherwise, I guess I should just continue following where pin 1 goes, to the 4051 and next the TL064.  Somehow though, I think my luck just isn't that great to accidentally bend just the right pin back that is causing the problem.  We shall see, we shall see.

Greg

--- In vintagesynthrepair@yahoogroups.com, "jammie" <jammie.emma@...> wrote:
Show quoted textHide quoted text
>
> check the cv dac and the sample and hold multiplexers
>   ----- Original Message ----- 
>   From: adhmzaiusz 
>   To: vintagesynthrepair@yahoogroups.com 
>   Sent: Wednesday, April 18, 2012 2:06 PM
>   Subject: [vintagesynthrepair] Progress Re: Jupiter 6 common no sound problem
> 
> 
>     
>   Hey everyone, just wanted to mention that I've made some progress with my JP6. Since I got it I always thought it was a little strange that on the 4 voice board the slave cpu was socketed when both the other cpus werent, so I decided to pop it out and reseat it just for the heck of it. While i was at it i reseated the Roland "B" ic (i think it is a eprom) as well. When I rebooted I was surprised to see that it finished autotune after about approx 10 seconds and there was sound. 
>   I think that when the JP6s freeze with the lfo they are locked up because they can't finish autotuning for any reason. Anyway, my 4 voice board seems to be quite messed up, almost sounds like everything is high pitched and non cv controlled. I guess that will be next on the list to sort out.
> 
>   Greg
> 
>   --- In vintagesynthrepair@yahoogroups.com, "adhmzaiusz" <adhmzaiusz@> wrote:
>   >
>   > Yea, its locked up for the most part. Lfo 2 speed can still be adjusted immediately, but it seemed that after I wait a while the panel controls seem to unlock, its not perfect as it seems that the number select buttons only work 1, 6-8. So 2-5 don't work.
>   > 
>   > Anyway, when I scope the reset inputs of the 3 CPUs I don't a locked voltage, which is normal. When I power on the machine i can see the voltage jump as a spike on each reset. So I'm assuming the reset works, as outlined on page 2b.
>   > 
>   > My scope is only a 20mhz but i can scope the other pins of the main cpu and i see what looks like all sorts of activity looks like pulse waves etc which I assume is normal.
>   > 
>   > I'm not so familiar with digital stuff, so i don't really know where to begin. I was hoping when I bought this that it would just be a failed power supply! Oh well 
>   > 
>   > Any further ideas? :)
>   > 
>   > greg
>   > 
>   > --- In vintagesynthrepair@yahoogroups.com, Malte Rogacki <gacki@> wrote:
>   > >
>   > > So did I get this right:
>   > > 
>   > > At first the machine seems to be completely locked up?
>   > > 
>   > > Then after a while the controls (buttons, LED's and so on) start to work
>   > > but there's still no sound?
>   > > 
>   > > There's one thing to keep in mind: The processors of the voice boards need
>   > > their reset pulse, too. They are supplied with that pulse from the main
>   > > processor board. So break out the oscilloscope and measure the situation on
>   > > pin 9 of all three processors.
>   > > If you have the service manual the reset procesure and the components are
>   > > described on page 2b.
>   > >
>   >
>

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