Vintage Synth Repair

Hi All,

My prophet 600 stopped making sound a few months back.  It was 
working fine before that.  I found if I cranked up the mixer trim & 
amp I could make out a sound & I was also able to distinguish any 
changes I made with each of the front pannel switches/POTs so they 
all work. I cannot make out any of the presets.

Any idea's I could try would be appreciated.

Thanks,

Steve

Hi Steve

From your post, not sure if you have little or no audio output from your
P600
volume wise.
Need more info.
As far as the presets not working or making sounds, it sounds like
your battery is dead.
This is used to keep the presets in memory.
If you take the P600 apart you can locate the battery on a PCB.
My multitrak had a Panasonic BR 2/3 A with solder tabs.
I found a replacement locally but Digi-Key had them, as well as a large
assortment of all types.
I unsoldered and replaced the old battery with a new one.
I then reloaded the factory patches from a wave file I found on the net.
Everything is fine now.

Also you can check the battery with a meter.
They usually are 3 to 3.6 volts DC
Could you save any of your sounds or patches into a preset?
If you have no presets the P600 will come up in a random state that may be
producing no noise or sounds.

Turn on the P600 and try to set up a patch, then save it.
Do his a couple of times and save to different presets.
Call each one of them up to see if they will stay in their respective
preset.
Then shut off the P600 for a minute then turn it on.
Try your previous presets.
If nothing or something different is there, it's probably your battery.
Have you backed up your presets before this either to tape or wavefile?
If so try to load them in and see if they hold.

Get back with more info on your problem.

Thanks
KS
----- Original Message -----

From: <broncosteven@...>
To: <vintagesynthrepair@yahoogroups.com>
Sent: Wednesday, April 04, 2001 9:53 PM
Subject: [vintagesynthrepair] Sequential Circuits Prophet 600


> Hi All,
>
> My prophet 600 stopped making sound a few months back.  It was
> working fine before that.  I found if I cranked up the mixer trim &
> amp I could make out a sound & I was also able to distinguish any
> changes I made with each of the front pannel switches/POTs so they
> all work. I cannot make out any of the presets.
>
> Any idea's I could try would be appreciated.
>
> Thanks,
>
> Steve
>
>
>
> To unsubscribe from this group, send an email to:
> vintagesynthrepair-unsubscribe@egroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>

If I trun it on & select a patch, after tuning, no sound is audible. 
If I crank up the volume on my mixer & tweak the front pannel control 
knobs I can just make out the sound.  At no time do I get a fully 
audible/usable sound.

I would like to try to replace the battery myself, is it easy to 
solder off? I haven't touched a soldering iron since High school (way 
back) but I want to learn how to do this kind of stuff.

Would the battery affect the volume?  If there is more than 1 thing 
wrong I may be better off having it serviced. 

I am not worried about presets as I want to learn how to program from 
scratch.

Thanks for the Help!

Steve
--- In vintagesynthrepair@y..., "ks" <ks@s...> wrote:
> Hi Steve
> 
> From your post, not sure if you have little or no audio output from 
your
> P600
> volume wise.
> Need more info.
> As far as the presets not working or making sounds, it sounds like
> your battery is dead.
> This is used to keep the presets in memory.
> If you take the P600 apart you can locate the battery on a PCB.
> My multitrak had a Panasonic BR 2/3 A with solder tabs.
> I found a replacement locally but Digi-Key had them, as well as a 
large
> assortment of all types.
> I unsoldered and replaced the old battery with a new one.
> I then reloaded the factory patches from a wave file I found on the 
net.
> Everything is fine now.
> 
> Also you can check the battery with a meter.
> They usually are 3 to 3.6 volts DC
> Could you save any of your sounds or patches into a preset?
> If you have no presets the P600 will come up in a random state that 
may be
> producing no noise or sounds.
> 
> Turn on the P600 and try to set up a patch, then save it.
> Do his a couple of times and save to different presets.
> Call each one of them up to see if they will stay in their 
respective
> preset.
> Then shut off the P600 for a minute then turn it on.
> Try your previous presets.
> If nothing or something different is there, it's probably your 
battery.
> Have you backed up your presets before this either to tape or 
wavefile?
> If so try to load them in and see if they hold.
> 
> Get back with more info on your problem.
> 
> Thanks
> KS
> ----- Original Message -----
> From: <broncosteven@y...>
> To: <vintagesynthrepair@y...>
> Sent: Wednesday, April 04, 2001 9:53 PM
> Subject: [vintagesynthrepair] Sequential Circuits Prophet 600
> 
> 
> > Hi All,
> >
> > My prophet 600 stopped making sound a few months back.  It was
> > working fine before that.  I found if I cranked up the mixer trim 
&
> > amp I could make out a sound & I was also able to distinguish any
> > changes I made with each of the front pannel switches/POTs so they
> > all work. I cannot make out any of the presets.
> >
> > Any idea's I could try would be appreciated.
> >
> > Thanks,
> >
> > Steve
> >
> >
> >
> > To unsubscribe from this group, send an email to:
> > vintagesynthrepair-unsubscribe@egroups.com
> >
> >
> >
> > Your use of Yahoo! Groups is subject to 
http://docs.yahoo.com/info/terms/
> >

Hi Steve

Sounds like you have  more than battery problems.
Does the P600 have headphone outputs.
Do these work?
I'll have to dig up the P600 schematic to take a look at the circuit.
You can test the battery with a voltmeter or DMM. as i stated earlier.
Someone that knows how to use a scope should be able to pinpoint exactly
where you're losing
the audio signal.
Also the obvious. Check the Power supply for correct voltages.

Keep in touch
KS

-----Original Message-----
From: broncosteven@... <broncosteven@...>
To: vintagesynthrepair@yahoogroups.com <vintagesynthrepair@yahoogroups.com>
Date: Friday, April 06, 2001 12:06 PM

Subject: [vintagesynthrepair] Re: Sequential Circuits Prophet 600


>If I trun it on & select a patch, after tuning, no sound is audible.
>If I crank up the volume on my mixer & tweak the front pannel control
>knobs I can just make out the sound.  At no time do I get a fully
>audible/usable sound.
>
>I would like to try to replace the battery myself, is it easy to
>solder off? I haven't touched a soldering iron since High school (way
>back) but I want to learn how to do this kind of stuff.
>
>Would the battery affect the volume?  If there is more than 1 thing
>wrong I may be better off having it serviced.
>
>I am not worried about presets as I want to learn how to program from
>scratch.
>
>Thanks for the Help!
>
>Steve
>--- In vintagesynthrepair@y..., "ks" <ks@s...> wrote:
>> Hi Steve
>>
>> From your post, not sure if you have little or no audio output from
>your
>> P600
>> volume wise.
>> Need more info.
>> As far as the presets not working or making sounds, it sounds like
>> your battery is dead.
>> This is used to keep the presets in memory.
>> If you take the P600 apart you can locate the battery on a PCB.
>> My multitrak had a Panasonic BR 2/3 A with solder tabs.
>> I found a replacement locally but Digi-Key had them, as well as a
>large
>> assortment of all types.
>> I unsoldered and replaced the old battery with a new one.
>> I then reloaded the factory patches from a wave file I found on the
>net.
>> Everything is fine now.
>>
>> Also you can check the battery with a meter.
>> They usually are 3 to 3.6 volts DC
>> Could you save any of your sounds or patches into a preset?
>> If you have no presets the P600 will come up in a random state that
>may be
>> producing no noise or sounds.
>>
>> Turn on the P600 and try to set up a patch, then save it.
>> Do his a couple of times and save to different presets.
>> Call each one of them up to see if they will stay in their
>respective
>> preset.
>> Then shut off the P600 for a minute then turn it on.
>> Try your previous presets.
>> If nothing or something different is there, it's probably your
>battery.
>> Have you backed up your presets before this either to tape or
>wavefile?
>> If so try to load them in and see if they hold.
>>
>> Get back with more info on your problem.
>>
>> Thanks
>> KS
>> ----- Original Message -----
>> From: <broncosteven@y...>
>> To: <vintagesynthrepair@y...>
>> Sent: Wednesday, April 04, 2001 9:53 PM
>> Subject: [vintagesynthrepair] Sequential Circuits Prophet 600
>>
>>
>> > Hi All,
>> >
>> > My prophet 600 stopped making sound a few months back.  It was
>> > working fine before that.  I found if I cranked up the mixer trim
>&
>> > amp I could make out a sound & I was also able to distinguish any
>> > changes I made with each of the front pannel switches/POTs so they
>> > all work. I cannot make out any of the presets.
>> >
>> > Any idea's I could try would be appreciated.
>> >
>> > Thanks,
>> >
>> > Steve
>> >
>> >
>> >
>> > To unsubscribe from this group, send an email to:
>> > vintagesynthrepair-unsubscribe@egroups.com
>> >
>> >
>> >
>> > Your use of Yahoo! Groups is subject to
>http://docs.yahoo.com/info/terms/
>> >
>
>
>To unsubscribe from this group, send an email to:
>vintagesynthrepair-unsubscribe@egroups.com
>
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>