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Prophet 10

Prophet 10

2008-04-06 by fsimon100

Does anyone have a descent schematic of a Prophet 10? I found a free 
one and it is hard to read. Plus it has a 12volt regulator in the 
schematic where I actually had two 5v and I put in the 12 and fried a 
dual flip flop for sure because it buned me when I touched it. Then I 
looked deeper in the connectors and see 12v is not needed and I messed 
up. I could share the schematic to show it was wrong if anyone wants to 
see. But now I have +15,-15,+5,+5 in TO-3 high power regs and replaced 
the flipflop and all voltages are good but unit is still down. I may 
fried something else but once the flip flop shorted it pulled the 
supply down. 

I bought this non working for $30 but would love to fix it.

Prophet 10

2010-06-29 by Frank Simon

My P10 is wacko. Sometimes I turn it on it lights up and acts like it wants to work but if I cycle the power nothing will light except the tune LED as if it is in tune mode but doesn't time out. If I cycle power something different may happen. I think the PCB3 board has issues would anyone agree? All Power supplies are good with DVM but I see noise ripple on supplies with .2 to .5V that seems high to me. It is not 60 cycle ripple but very random noisy ripple. Not sure of best trouble shooting approach of this board. My P10 shematic is freeby with poor zoom in ability. My P5 is better but refernce designators and power supplies seem different. Anybody got a good service manual or advice?
Frank

Re: Prophet 10

2010-06-30 by Frank Simon

Are there any Prophet 10 owners that can answer a question for me? Can you hear your transformer hum when you power up?
Frank
Show quoted textHide quoted text
----- Original Message -----
Sent: Monday, June 28, 2010 11:24 PM
Subject: Prophet 10

My P10 is wacko. Sometimes I turn it on it lights up and acts like it wants to work but if I cycle the power nothing will light except the tune LED as if it is in tune mode but doesn't time out. If I cycle power something different may happen. I think the PCB3 board has issues would anyone agree? All Power supplies are good with DVM but I see noise ripple on supplies with .2 to .5V that seems high to me. It is not 60 cycle ripple but very random noisy ripple. Not sure of best trouble shooting approach of this board. My P10 shematic is freeby with poor zoom in ability. My P5 is better but refernce designators and power supplies seem different. Anybody got a good service manual or advice?
Frank

RE: [vintagesynthrepair] Re: Prophet 10

2010-06-30 by Brian Fuller

Bad caps?
Show quoted textHide quoted text
From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Frank Simon
Sent: Tuesday, June 29, 2010 11:31 PM
To: vintagesynthrepair@yahoogroups.com; SequentialCircuits@yahoogroups.com
Subject: [vintagesynthrepair] Re: Prophet 10

 

  

Are there any Prophet 10 owners that can answer a question for me? Can you
hear your transformer hum when you power up?

Frank

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

From: Frank Simon <mailto:FSIMON001@...>  

To: vintagesynthrepair@yahoogroups.com ; SequentialCircuits@yahoogroups.com 

Sent: Monday, June 28, 2010 11:24 PM

Subject: Prophet 10

 

My P10 is wacko. Sometimes I turn it on it lights up and acts like it wants
to work but if I cycle the power nothing will light except the tune LED as
if it is in tune mode but doesn't time out. If I cycle power something
different may happen. I think the PCB3 board has issues would anyone agree?
All Power supplies are good with DVM but I see noise ripple on supplies with
.2 to .5V that seems high to me. It is not 60 cycle ripple but very random
noisy ripple. Not sure of best trouble shooting approach of this board. My
P10 shematic is freeby with poor zoom in ability. My P5 is better but
refernce designators and power supplies seem different. Anybody got a good
service manual or advice?

Frank

Re: [vintagesynthrepair] Re: Prophet 10

2010-06-30 by arthurok

do you own an esr capacitor tester?
try bridging the filter caps and see if the ripple drops significantly
Show quoted textHide quoted text
----- Original Message -----
Sent: Tuesday, June 29, 2010 10:30 PM
Subject: [vintagesynthrepair] Re: Prophet 10

Are there any Prophet 10 owners that can answer a question for me? Can you hear your transformer hum when you power up?
Frank
----- Original Message -----
Sent: Monday, June 28, 2010 11:24 PM
Subject: Prophet 10

My P10 is wacko. Sometimes I turn it on it lights up and acts like it wants to work but if I cycle the power nothing will light except the tune LED as if it is in tune mode but doesn't time out. If I cycle power something different may happen. I think the PCB3 board has issues would anyone agree? All Power supplies are good with DVM but I see noise ripple on supplies with .2 to .5V that seems high to me. It is not 60 cycle ripple but very random noisy ripple. Not sure of best trouble shooting approach of this board. My P10 shematic is freeby with poor zoom in ability. My P5 is better but refernce designators and power supplies seem different. Anybody got a good service manual or advice?
Frank

RE: [vintagesynthrepair] Re: Prophet 10

2010-06-30 by Brian

Hi Frank

 

All transformers hum to a greater or lesser degree when powered up.  This
may be a loose lamination rattling or it may be a less than perfect gap
creating what is known as magnetostriction; this is an oscillation of the
air across the gap.

 

On audio equipment it is normal for a manufacturer to minimise all such
noises, nevertheless some noise will remain.

 

Regards

Brian G3OYU
Show quoted textHide quoted text
From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Frank Simon
Sent: 30 June 2010 4:31
To: vintagesynthrepair@yahoogroups.com; SequentialCircuits@yahoogroups.com
Subject: [vintagesynthrepair] Re: Prophet 10

 

  

Are there any Prophet 10 owners that can answer a question for me? Can you
hear your transformer hum when you power up?

Frank

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

From: Frank Simon <mailto:FSIMON001@...>  

To: vintagesynthrepair@yahoogroups.com ; SequentialCircuits@yahoogroups.com 

Sent: Monday, June 28, 2010 11:24 PM

Subject: Prophet 10

 

My P10 is wacko. Sometimes I turn it on it lights up and acts like it wants
to work but if I cycle the power nothing will light except the tune LED as
if it is in tune mode but doesn't time out. If I cycle power something
different may happen. I think the PCB3 board has issues would anyone agree?
All Power supplies are good with DVM but I see noise ripple on supplies with
.2 to .5V that seems high to me. It is not 60 cycle ripple but very random
noisy ripple. Not sure of best trouble shooting approach of this board. My
P10 shematic is freeby with poor zoom in ability. My P5 is better but
refernce designators and power supplies seem different. Anybody got a good
service manual or advice?

Frank

Re: [vintagesynthrepair] Re: Prophet 10

2010-06-30 by Miguel Mendoza

I don't hear any hum in my Prophet 10

Sent: Wednesday, June 30, 2010 5:30 AM
Subject: [vintagesynthrepair] Re: Prophet 10

Are there any Prophet 10 owners that can answer a question for me? Can you hear your transformer hum when you power up?
Frank
----- Original Message -----
Sent: Monday, June 28, 2010 11:24 PM
Subject: Prophet 10

My P10 is wacko. Sometimes I turn it on it lights up and acts like it wants to work but if I cycle the power nothing will light except the tune LED as if it is in tune mode but doesn't time out. If I cycle power something different may happen. I think the PCB3 board has issues would anyone agree? All Power supplies are good with DVM but I see noise ripple on supplies with .2 to .5V that seems high to me. It is not 60 cycle ripple but very random noisy ripple. Not sure of best trouble shooting approach of this board. My P10 shematic is freeby with poor zoom in ability. My P5 is better but refernce designators and power supplies seem different. Anybody got a good service manual or advice?
Frank

Re: [vintagesynthrepair] Re: Prophet 10

2010-06-30 by Frank Simon

OK, That's what I'm after. Mine does hum but the Regulated voltages are all correct. I did make a comment on ripple but not so sure that is an issue. I would like to move on to the computer board after I bless the PSU. Can anyone guess why sometimes the the LEDs light and and somtimes they don't? Does that seem to be Processor related? I would rather chase audio. Also can I unplug all the boards off the Computer board except power for troubleshooting?
Show quoted textHide quoted text
----- Original Message -----
Sent: Wednesday, June 30, 2010 4:59 AM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

I don't hear any hum in my Prophet 10

Sent: Wednesday, June 30, 2010 5:30 AM
Subject: [vintagesynthrepair] Re: Prophet 10

Are there any Prophet 10 owners that can answer a question for me? Can you hear your transformer hum when you power up?
Frank
----- Original Message -----
Sent: Monday, June 28, 2010 11:24 PM
Subject: Prophet 10

My P10 is wacko. Sometimes I turn it on it lights up and acts like it wants to work but if I cycle the power nothing will light except the tune LED as if it is in tune mode but doesn't time out. If I cycle power something different may happen. I think the PCB3 board has issues would anyone agree? All Power supplies are good with DVM but I see noise ripple on supplies with .2 to .5V that seems high to me. It is not 60 cycle ripple but very random noisy ripple. Not sure of best trouble shooting approach of this board. My P10 shematic is freeby with poor zoom in ability. My P5 is better but refernce designators and power supplies seem different. Anybody got a good service manual or advice?
Frank

Re: [vintagesynthrepair] Re: Prophet 10

2010-06-30 by Miguel Mendoza

I'm not very sure but perhaps there is any voice that can't be tuned properly (regarding the led behaviour). Mine one is working properly but I have to wait 2-5 minutes until the knobs start to work fine, mainly the filter cut off.
I have a good service manual but only on paper, I bought it in Manual Minor. If you have any concrete question about the schematics perhaps I could help.
Is the hum coming into the audio path?

Sent: Wednesday, June 30, 2010 1:56 PM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

OK, That's what I'm after. Mine does hum but the Regulated voltages are all correct. I did make a comment on ripple but not so sure that is an issue. I would like to move on to the computer board after I bless the PSU. Can anyone guess why sometimes the the LEDs light and and somtimes they don't? Does that seem to be Processor related? I would rather chase audio. Also can I unplug all the boards off the Computer board except power for troubleshooting?
----- Original Message -----
Sent: Wednesday, June 30, 2010 4:59 AM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

I don't hear any hum in my Prophet 10

Sent: Wednesday, June 30, 2010 5:30 AM
Subject: [vintagesynthrepair] Re: Prophet 10

Are there any Prophet 10 owners that can answer a question for me? Can you hear your transformer hum when you power up?
Frank
----- Original Message -----
Sent: Monday, June 28, 2010 11:24 PM
Subject: Prophet 10

My P10 is wacko. Sometimes I turn it on it lights up and acts like it wants to work but if I cycle the power nothing will light except the tune LED as if it is in tune mode but doesn't time out. If I cycle power something different may happen. I think the PCB3 board has issues would anyone agree? All Power supplies are good with DVM but I see noise ripple on supplies with .2 to .5V that seems high to me. It is not 60 cycle ripple but very random noisy ripple. Not sure of best trouble shooting approach of this board. My P10 shematic is freeby with poor zoom in ability. My P5 is better but refernce designators and power supplies seem different. Anybody got a good service manual or advice?
Frank

Re: Prophet 10

2010-06-30 by Frank

Thanks Miquel,
I have a schematic but that is all. Does your manual have any diagnostic/troubleshooting help? Or is it more of a user manual? Does it have specs for voltage regulation/ripple? Any text on troubleshooting the computer section would be appreciated.


--- In vintagesynthrepair@yahoogroups.com, "Miguel Mendoza" <miguel@...> wrote:
Show quoted textHide quoted text
>
> I'm not very sure but perhaps there is any voice that can't be tuned properly (regarding the led behaviour). Mine one is working properly but I have to wait 2-5 minutes until the knobs start to work fine, mainly the filter cut off. 
> 
> I have a good service manual but only on paper, I bought it in Manual Minor. If you have any concrete question about the schematics perhaps I could help.
> 
> Is the hum coming into the audio path?
> 
> 
> 
> 
> From: Frank Simon 
> Sent: Wednesday, June 30, 2010 1:56 PM
> To: vintagesynthrepair@yahoogroups.com 
> Subject: Re: [vintagesynthrepair] Re: Prophet 10
> 
> 
>   
> 
> OK, That's what I'm after. Mine does hum but the Regulated voltages are all correct. I did make a comment on ripple but not so sure that is an issue. I would like to move on to the computer board after I bless the PSU. Can anyone guess why sometimes the the LEDs light and and somtimes they don't? Does that seem to be Processor related? I would rather chase audio. Also can I unplug all the boards off the Computer board except power for troubleshooting?
> 
> 
>   ----- Original Message ----- 
>   From: Miguel Mendoza 
>   To: vintagesynthrepair@yahoogroups.com 
>   Sent: Wednesday, June 30, 2010 4:59 AM
>   Subject: Re: [vintagesynthrepair] Re: Prophet 10
> 
> 
>     
> 
>   I don't hear any hum in my Prophet 10 
> 
> 
>   From: Frank Simon 
>   Sent: Wednesday, June 30, 2010 5:30 AM
>   To: vintagesynthrepair@yahoogroups.com ; SequentialCircuits@yahoogroups.com 
>   Subject: [vintagesynthrepair] Re: Prophet 10
> 
> 
>     
> 
>   Are there any Prophet 10 owners that can answer a question for me? Can you hear your transformer hum when you power up?
>   Frank
>     ----- Original Message ----- 
>     From: Frank Simon 
>     To: vintagesynthrepair@yahoogroups.com ; SequentialCircuits@yahoogroups.com 
>     Sent: Monday, June 28, 2010 11:24 PM
>     Subject: Prophet 10
> 
> 
>     My P10 is wacko. Sometimes I turn it on it lights up and acts like it wants to work but if I cycle the power nothing will light except the tune LED as if it is in tune mode but doesn't time out. If I cycle power something different may happen. I think the PCB3 board has issues would anyone agree? All Power supplies are good with DVM but I see noise ripple on supplies with .2 to .5V that seems high to me. It is not 60 cycle ripple but very random noisy ripple. Not sure of best trouble shooting approach of this board. My P10 shematic is freeby with poor zoom in ability. My P5 is better but refernce designators and power supplies seem different. Anybody got a good service manual or advice?
>     Frank
>

Re: [vintagesynthrepair] Re: Prophet 10

2010-06-30 by Miguel Mendoza

It's an operation manual with a service chapter. For the CPU, the adjustments are the same than the P5 excepting for the double voices, so if you have the P5 service manual it should be there in section 4 (as the P10 manual says).
Regarding the power supply:
- The output of U602 +15 voltage regulator should read +15.000 v. adjusting R603
- The output (pin 2) of U604 -15 regulator should read -15000 v. adjusting R606
It's the only procedure listed.
There is also a section regarding diagnostics but you need to insert PROM MTEST.3.10 and TENPROG.1 in U304 and U306 respectively. I have no idea where to get those PROMS...
Hope this helps.
Regards.
Miguel.

From: Frank
Sent: Wednesday, June 30, 2010 7:15 PM
Subject: [vintagesynthrepair] Re: Prophet 10


Thanks Miquel,
I have a schematic but that is all. Does your manual have any diagnostic/troubleshooting help? Or is it more of a user manual? Does it have specs for voltage regulation/ripple? Any text on troubleshooting the computer section would be appreciated.

--- In vintagesynthrepair@yahoogroups.com, "Miguel Mendoza" wrote:
>
> I'm not very sure but perhaps there is any voice that can't be tuned properly (regarding the led behaviour). Mine one is working properly but I have to wait 2-5 minutes until the knobs start to work fine, mainly the filter cut off.
>
> I have a good service manual but only on paper, I bought it in Manual Minor. If you have any concrete question about the schematics perhaps I could help.
>
> Is the hum coming into the audio path?
>
>
>
>
> From: Frank Simon
> Sent: Wednesday, June 30, 2010 1:56 PM
> To: vintagesynthrepair@yahoogroups.com
> Subject: Re: [vintagesynthrepair] Re: Prophet 10
>
>
>
>
> OK, That's what I'm after. Mine does hum but the Regulated voltages are all correct. I did make a comment on ripple but not so sure that is an issue. I would like to move on to the computer board after I bless the PSU. Can anyone guess why sometimes the the LEDs light and and somtimes they don't? Does that seem to be Processor related? I would rather chase audio. Also can I unplug all the boards off the Computer board except power for troubleshooting?
>
>
> ----- Original Message -----
> From: Miguel Mendoza
> To: vintagesynthrepair@yahoogroups.com
> Sent: Wednesday, June 30, 2010 4:59 AM
> Subject: Re: [vintagesynthrepair] Re: Prophet 10
>
>
>
>
> I don't hear any hum in my Prophet 10
>
>
> From: Frank Simon
> Sent: Wednesday, June 30, 2010 5:30 AM
> To: vintagesynthrepair@yahoogroups.com ; SequentialCircuits@yahoogroups.com
> Subject: [vintagesynthrepair] Re: Prophet 10
>
>
>
>
> Are there any Prophet 10 owners that can answer a question for me? Can you hear your transformer hum when you power up?
> Frank
> ----- Original Message -----
> From: Frank Simon
> To: vintagesynthrepair@yahoogroups.com ; SequentialCircuits@yahoogroups.com
> Sent: Monday, June 28, 2010 11:24 PM
> Subject: Prophet 10
>
>
> My P10 is wacko. Sometimes I turn it on it lights up and acts like it wants to work but if I cycle the power nothing will light except the tune LED as if it is in tune mode but doesn't time out. If I cycle power something different may happen. I think the PCB3 board has issues would anyone agree? All Power supplies are good with DVM but I see noise ripple on supplies with .2 to .5V that seems high to me. It is not 60 cycle ripple but very random noisy ripple. Not sure of best trouble shooting approach of this board. My P10 shematic is freeby with poor zoom in ability. My P5 is better but refernce designators and power supplies seem different. Anybody got a good service manual or advice?
> Frank
>

Re: [vintagesynthrepair] Re: Prophet 10

2010-06-30 by arthurok

he should invest in a low cost esr meter from mat electronics
ive had one of theirs for several years and its very usefull when going through a piece of equipment
just remember that a shoted lytic shows a low esr so i test lytics in circuit with a low power ohmmeter too.
Show quoted textHide quoted text
----- Original Message -----
Sent: Wednesday, June 30, 2010 6:56 AM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

OK, That's what I'm after. Mine does hum but the Regulated voltages are all correct. I did make a comment on ripple but not so sure that is an issue. I would like to move on to the computer board after I bless the PSU. Can anyone guess why sometimes the the LEDs light and and somtimes they don't? Does that seem to be Processor related? I would rather chase audio. Also can I unplug all the boards off the Computer board except power for troubleshooting?
----- Original Message -----
Sent: Wednesday, June 30, 2010 4:59 AM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

I don't hear any hum in my Prophet 10

Sent: Wednesday, June 30, 2010 5:30 AM
Subject: [vintagesynthrepair] Re: Prophet 10

Are there any Prophet 10 owners that can answer a question for me? Can you hear your transformer hum when you power up?
Frank
----- Original Message -----
Sent: Monday, June 28, 2010 11:24 PM
Subject: Prophet 10

My P10 is wacko. Sometimes I turn it on it lights up and acts like it wants to work but if I cycle the power nothing will light except the tune LED as if it is in tune mode but doesn't time out. If I cycle power something different may happen. I think the PCB3 board has issues would anyone agree? All Power supplies are good with DVM but I see noise ripple on supplies with .2 to .5V that seems high to me. It is not 60 cycle ripple but very random noisy ripple. Not sure of best trouble shooting approach of this board. My P10 shematic is freeby with poor zoom in ability. My P5 is better but refernce designators and power supplies seem different. Anybody got a good service manual or advice?
Frank

Re: [vintagesynthrepair] Re: Prophet 10

2010-07-02 by Frank Simon

I have decided to do a capacitor job on my P10 but there are a couple Tantalum caps I can't identify on my sequencer board and my schematics doesn't have the sequencer option. I think it is PCB9. One is labeled C-019 and I can read V47 which I assume 0.47uF the other is C-032 with nothing but color code. If the cap is standing up it is a yellow dipped cap. Purple is the top color (maybe violet)and blue is below it. They are not color bands like a resistor but only them two colors that cover the entire componet with big thick color bands. Any help appreciated.
Doeas anyone have a electronics store to by caps cheap?
Show quoted textHide quoted text
----- Original Message -----
From: arthurok
Sent: Wednesday, June 30, 2010 4:29 PM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

he should invest in a low cost esr meter from mat electronics
ive had one of theirs for several years and its very usefull when going through a piece of equipment
just remember that a shoted lytic shows a low esr ; so i test lytics in circuit with a low power ohmmeter too.
----- Original Message -----
Sent: Wednesday, June 30, 2010 6:56 AM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

OK, That's what I'm after. Mine does hum but the Regulated voltages are all correct. I did make a comment on ripple but not so sure that is an issue. I would like to move on to the computer board after I bless the PSU. Can anyone guess why sometimes the the LEDs light and and somtimes they don't? Does that seem to be Processor related? I would rather chase audio. Also can I unplug all the boards off the Computer board except power for troubleshooting?
----- Original Message -----
Sent: Wednesday, June 30, 2010 4:59 AM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

I don't hear any hum in my Prophet 10

Sent: Wednesday, June 30, 2010 5:30 AM
Subject: [vintagesynthrepair] Re: Prophet 10

Are there any Prophet 10 owners that can answer a question for me? Can you hear your transformer hum when you power up?
Frank
----- Original Message -----
Sent: Monday, June 28, 2010 11:24 PM
Subject: Prophet 10

My P10 is wacko. Sometimes I turn it on it lights up and acts like it wants to work but if I cycle the power nothing will light except the tune LED as if it is in tune mode but doesn't time out. If I cycle power something different may happen. I think the PCB3 board has issues would anyone agree? All Power supplies are good with DVM but I see noise ripple on supplies with .2 to .5V that seems high to me. It is not 60 cycle ripple but very random noisy ripple. Not sure of best trouble shooting approach of this board. My P10 shematic is freeby with poor zoom in ability. My P5 is better but refernce designators and power supplies seem different. Anybody got a good service manual or advice?
Frank

Re: [vintagesynthrepair] Re: Prophet 10

2010-07-02 by Arto Koivisto

> nothing but color code. If the cap is standing up it is a yellow dipped 
> cap. Purple is the top color (maybe violet)and blue is below it. They 
> are not color bands like a resistor but only them two colors that cover 
> the entire componet with big thick color bands. Any help appreciated.

For those colors, this online calculator suggests its a 76\ufffdF 100V 20% 
capacitor:

http://www.csgnetwork.com/capcccalc.html

Seems a bit of a weird size for a capacitor in a sequencer circuit, so 
I'm wondering might your problematic capacitor be nanofarads instead? If 
it was 76\ufffdF, it'd most likely be a electrolythic cap too.

Have you tried pulling the part from the board and measuring the 
capacitance? This way, you might get some pointers towards hitting the 
right decimal at least.. Any similar caps elsewhere on the other boards 
that you have schematics for? Or have you identified what sub-circuit 
the cap connects to (or is a part of)? F.ex. if it belongs to some 
microcontroller clock osc circuit, it could also be picofarads.

Other than that, maybe flip a coin for a 680nF or a 68nF ceramic and 
hope for the best ;)

.Arto.
-- 
http://amazingdiy.wordpress.com/
http://kewlers.scene.org/bitchard/
http://www.holyfeather.com/outerspacealliance

Re: [vintagesynthrepair] Re: Prophet 10

2010-07-02 by GB

It might be yellow blue something. Sometimes the colors are a little hard to determine after so long (heat/dirt/etc).
GB
Show quoted textHide quoted text
----- Original Message -----
Sent: Thursday, July 01, 2010 10:09 PM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

> nothing but color code. If the cap is standing up it is a yellow dipped
> cap. Purple is the top color (maybe violet)and blue is below it. They
> are not color bands like a resistor but only them two colors that cover
> the entire componet with big thick color bands. Any help appreciated.

For those colors, this online calculator suggests its a 76µF 100V 20%
capacitor:

http://www.csgnetwork.com/capcccalc.html

Seems a bit of a weird size for a capacitor in a sequencer circuit, so
I'm wondering might your problematic capacitor be nanofarads instead? If
it was 76µF, it'd most likely be a electrolythic cap too.

Have you tried pulling the part from the board and measuring the
capacitance? This way, you might get some pointers towards hitting the
right decimal at least.. Any similar caps elsewhere on the other boards
that you have schematics for? Or have you identified what sub-circuit
the cap connects to (or is a part of)? F.ex. if it belongs to some
microcontroller clock osc circuit, it could also be picofarads.

Other than that, maybe flip a coin for a 680nF or a 68nF ceramic and
hope for the best ;)

.Arto.
--
http://amazingdiy.wordpress.com/
http://kewlers.scene.org/bitchard/
http://www.holyfeather.com/outerspacealliance

Re: [vintagesynthrepair] Re: Prophet 10

2010-07-02 by Frank Simon

That would make more sense yellow violet blue...476...47uF. It has to be that thanks GB. It is one of the biggest tantalums in the Synth
Show quoted textHide quoted text
----- Original Message -----
From: GB
Sent: Friday, July 02, 2010 9:09 AM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

It might be yellow blue something. Sometimes the colors are a little hard to determine after so long (heat/dirt/etc).
GB
----- Original Message -----
Sent: Thursday, July 01, 2010 10:09 PM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

> nothing but color code. If the cap is standing up it is a yellow dipped
> cap. Purple is the top color (maybe violet)and blue is below it. They
> are not color bands like a resistor but only them two colors that cover
> the entire componet with big thick color bands. Any help appreciated.

For those colors, this online calculator suggests its a 76µF 100V 20%
capacitor:

http://www.csgnetwork.com/capcccalc.html

Seems a bit of a weird size for a capacitor in a sequencer circuit, so
I'm wondering might your problematic capacitor be nanofarads instead? If
it was 76µF, it'd most likely be a electrolythic cap too.

Have you tried pulling the part from the board and measuring the
capacitance? This way, you might get some pointers towards hitting the
right decimal at least.. Any similar caps elsewhere on the other boards
that you have schematics for? Or have you identified what sub-circuit
the cap connects to (or is a part of)? F.ex. if it belongs to some
microcontroller clock osc circuit, it could also be picofarads.

Other than that, maybe flip a coin for a 680nF or a 68nF ceramic and
hope for the best ;)

.Arto.
--
http://amazingdiy.wordpress.com/
http://kewlers.scene.org/bitchard/
http://www.holyfeather.com/outerspacealliance

Re: [vintagesynthrepair] Re: Prophet 10

2010-07-02 by GB

I don't think it's tantalum either. Google for a photo of a similar looking one. I think it's a film cap but I can't remember what kind of film. Keep looking you are getting closer.
GB
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----- Original Message -----
Sent: Friday, July 02, 2010 2:23 PM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

That would make more sense yellow violet blue...476...47uF. It has to be that thanks GB. It is one of the biggest tantalums in the Synth
----- Original Message -----
From: GB
Sent: Friday, July 02, 2010 9:09 AM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

It might be yellow blue something. Sometimes the colors are a little hard to determine after so long (heat/dirt/etc).
GB
----- Original Message -----
Sent: Thursday, July 01, 2010 10:09 PM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

> nothing but color code. If the cap is standing up it is a yellow dipped
> cap. Purple is the top color (maybe violet)and blue is below it. They
> are not color bands like a resistor but only them two colors that cover
> the entire componet with big thick color bands. Any help appreciated.

For those colors, this online calculator suggests its a 76µF 100V 20%
capacitor:

http://www.csgnetwork.com/capcccalc.html

Seems a bit of a weird size for a capacitor in a sequencer circuit, so
I'm wondering might your problematic capacitor be nanofarads instead? If
it was 76µF, it'd most likely be a electrolythic cap too.

Have you tried pulling the part from the board and measuring the
capacitance? This way, you might get some pointers towards hitting the
right decimal at least.. Any similar caps elsewhere on the other boards
that you have schematics for? Or have you identified what sub-circuit
the cap connects to (or is a part of)? F.ex. if it belongs to some
microcontroller clock osc circuit, it could also be picofarads.

Other than that, maybe flip a coin for a 680nF or a 68nF ceramic and
hope for the best ;)

.Arto.
--
http://amazingdiy.wordpress.com/
http://kewlers.scene.org/bitchard/
http://www.holyfeather.com/outerspacealliance

Re: [vintagesynthrepair] Re: Prophet 10

2010-07-02 by GB

Apparently now they are called tropical fish caps .
GB
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----- Original Message -----
Sent: Friday, July 02, 2010 2:23 PM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

That would make more sense yellow violet blue...476...47uF. It has to be that thanks GB. It is one of the biggest tantalums in the Synth
----- Original Message -----
From: GB
Sent: Friday, July 02, 2010 9:09 AM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

It might be yellow blue something. Sometimes the colors are a little hard to determine after so long (heat/dirt/etc).
GB
----- Original Message -----
Sent: Thursday, July 01, 2010 10:09 PM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

> nothing but color code. If the cap is standing up it is a yellow dipped
> cap. Purple is the top color (maybe violet)and blue is below it. They
> are not color bands like a resistor but only them two colors that cover
> the entire componet with big thick color bands. Any help appreciated.

For those colors, this online calculator suggests its a 76µF 100V 20%
capacitor:

http://www.csgnetwork.com/capcccalc.html

Seems a bit of a weird size for a capacitor in a sequencer circuit, so
I'm wondering might your problematic capacitor be nanofarads instead? If
it was 76µF, it'd most likely be a electrolythic cap too.

Have you tried pulling the part from the board and measuring the
capacitance? This way, you might get some pointers towards hitting the
right decimal at least.. Any similar caps elsewhere on the other boards
that you have schematics for? Or have you identified what sub-circuit
the cap connects to (or is a part of)? F.ex. if it belongs to some
microcontroller clock osc circuit, it could also be picofarads.

Other than that, maybe flip a coin for a 680nF or a 68nF ceramic and
hope for the best ;)

.Arto.
--
http://amazingdiy.wordpress.com/
http://kewlers.scene.org/bitchard/
http://www.holyfeather.com/outerspacealliance

Re: [vintagesynthrepair] Re: Prophet 10

2010-07-03 by Frank Simon

This was a real hassle but I did it so everyone can learn from it. It is a tantalum the only issue is the multiplyer dot is faded. I uploaded a pic in photos called Prophet 10 Tantalum.
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----- Original Message -----
From: GB
Sent: Friday, July 02, 2010 6:52 PM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

I don't think it's tantalum either. Google for a photo of a similar looking one. I think it's a film cap but I can't remember what kind of film. Keep looking you are getting closer.
;
GB
----- Original Message -----
Sent: Friday, July 02, 2010 2:23 PM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

That would make more sense yellow violet blue...476...47uF. It has to be that thanks GB. It is one of the biggest tantalums in the Synth
----- Original Message -----
From: GB
Sent: Friday, July 02, 2010 9:09 AM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

It might be yellow blue something. Sometimes the colors are a little hard to determine after so long (heat/dirt/etc).
GB
----- Original Message -----
Sent: Thursday, July 01, 2010 10:09 PM
Subject: Re: [vintagesynthrepair] Re: Prophet 10

;

> nothing but color code. If the cap is standing up it is a yellow dipped
> cap. Purple is the top color (maybe violet)and blue is below it. They
> are not color bands like a resistor but only them two colors that cover
> the entire componet with big thick color bands. Any help appreciated.

For those colors, this online calculator suggests its a 76µF 100V 20%
capacitor:

http://www.csgnetwork.com/capcccalc.html

Seems a bit of a weird size for a capacitor in a sequencer circuit, so
I'm wondering might your problematic capacitor be nanofarads instead? If
it was 76µF, it'd most likely be a electrolythic cap too.

Have you tried pulling the part from the board and measuring the
capacitance? This way, you might get some pointers towards hitting the
right decimal at least.. Any similar caps elsewhere on the other boards
that you have schematics for? Or have you identified what sub-circuit
the cap connects to (or is a part of)? F.ex. if it belongs to some
microcontroller clock osc circuit, it could also be picofarads.

Other than that, maybe flip a coin for a 680nF or a 68nF ceramic and
hope for the best ;)

.Arto.
--
http://amazingdiy.wordpress.com/
http://kewlers.scene.org/bitchard/
http://www.holyfeather.com/outerspacealliance

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